id stringlengths 1 5 | text stringlengths 472 972 | title stringclasses 280 values | embeddings listlengths 768 768 |
|---|---|---|---|
9301 | the superoxide is preferentially formed for the larger alkali metals where the more complex anions are not polarised. (The oxides and peroxides for these alkali metals do exist, but do not form upon direct reaction of the metal with oxygen at standard conditions.) In addition, the small size of the Li and O ions contributes to their forming a stable ionic lattice structure. Under controlled conditions, however, all the alkali metals, with the exception of francium, are known to form their oxides, peroxides, and superoxides. The alkali metal peroxides and superoxides are powerful oxidising agents. Sodium peroxide and potassium superoxide | "Alkali metal" | [
-0.1264878362417221,
0.6814140677452087,
0.2576291561126709,
-0.11797766387462616,
-0.4650720953941345,
0.07365722209215164,
0.2657226026058197,
-0.7029541730880737,
0.2878893315792084,
-0.5993133783340454,
-0.24543730914592743,
0.053105227649211884,
-0.5953305959701538,
0.5402917265892029... |
9302 | react with carbon dioxide to form the alkali metal carbonate and oxygen gas, which allows them to be used in submarine air purifiers; the presence of water vapour, naturally present in breath, makes the removal of carbon dioxide by potassium superoxide even more efficient. All the stable alkali metals except lithium can form red ozonides (MO) through low-temperature reaction of the powdered anhydrous hydroxide with ozone: the ozonides may be then extracted using liquid ammonia. They slowly decompose at standard conditions to the superoxides and oxygen, and hydrolyse immediately to the hydroxides when in contact with water. Potassium, rubidium, and | "Alkali metal" | [
0.07975149899721146,
0.744489848613739,
0.0405234768986702,
-0.029348494485020638,
0.14065343141555786,
0.13673080503940582,
0.20109033584594727,
-0.34610381722450256,
0.37024521827697754,
-0.05434370040893555,
-0.5034241676330566,
0.3569283187389374,
-0.5822793841362,
0.4312857985496521,
... |
9303 | caesium also form sesquioxides MO, which may be better considered peroxide disuperoxides, . Rubidium and caesium can form a great variety of suboxides with the metals in formal oxidation states below +1. Rubidium can form RbO and RbO (copper-coloured) upon oxidation in air, while caesium forms an immense variety of oxides, such as the ozonide CsO and several brightly coloured suboxides, such as CsO (bronze), CsO (red-violet), CsO (violet), CsO (dark green), CsO, CsO, as well as CsO. The last of these may be heated under vacuum to generate CsO. The alkali metals can also react analogously with the heavier | "Alkali metal" | [
0.08436300605535507,
0.6785485744476318,
-0.03248234838247299,
0.05143176391720772,
-0.48762795329093933,
0.12667815387248993,
0.14257793128490448,
-0.3129521310329437,
0.2313585877418518,
-0.33241239190101624,
-0.4084891676902771,
-0.043665625154972076,
-0.470991849899292,
0.6515768170356... |
9304 | chalcogens (sulfur, selenium, tellurium, and polonium), and all the alkali metal chalcogenides are known (with the exception of francium's). Reaction with an excess of the chalcogen can similarly result in lower chalcogenides, with chalcogen ions containing chains of the chalcogen atoms in question. For example, sodium can react with sulfur to form the sulfide (NaS) and various polysulfides with the formula NaS ("x" from 2 to 6), containing the ions. Due to the basicity of the Se and Te ions, the alkali metal selenides and tellurides are alkaline in solution; when reacted directly with selenium and tellurium, alkali metal polyselenides | "Alkali metal" | [
-0.1521795094013214,
0.4066552221775055,
0.2196265459060669,
0.25460776686668396,
-0.51861572265625,
0.001385481096804142,
0.15257880091667175,
-0.4137727916240692,
0.6277455687522888,
-0.3982018828392029,
-0.3638899326324463,
0.1316668838262558,
-0.24010170996189117,
0.7305852174758911,
... |
9305 | and polytellurides are formed along with the selenides and tellurides with the and ions. They may be obtained directly from the elements in liquid ammonia or when air is not present, and are colourless, water-soluble compounds that air oxidises quickly back to selenium or tellurium. The alkali metal polonides are all ionic compounds containing the Po ion; they are very chemically stable and can be produced by direct reaction of the elements at around 300–400 °C. The alkali metals are among the most electropositive elements on the periodic table and thus tend to bond ionically to the most electronegative elements | "Alkali metal" | [
0.1727089136838913,
0.2764486074447632,
0.28915655612945557,
0.12027512490749359,
-0.26629316806793213,
0.1386805772781372,
0.07866444438695908,
-0.37319985032081604,
0.49339091777801514,
-0.2169017642736435,
-0.34226512908935547,
0.09038475900888443,
-0.38063347339630127,
0.43876639008522... |
9306 | on the periodic table, the halogens (fluorine, chlorine, bromine, iodine, and astatine), forming salts known as the alkali metal halides. The reaction is very vigorous and can sometimes result in explosions. All twenty stable alkali metal halides are known; the unstable ones are not known, with the exception of sodium astatide, because of the great instability and rarity of astatine and francium. The most well-known of the twenty is certainly sodium chloride, otherwise known as common salt. All of the stable alkali metal halides have the formula MX where M is an alkali metal and X is a halogen. They | "Alkali metal" | [
-0.1352950632572174,
0.7122670412063599,
0.3652473986148834,
-0.05460799112915993,
-0.4214787483215332,
-0.02478606440126896,
0.09763891994953156,
-0.40560609102249146,
0.29926565289497375,
-0.22472620010375977,
-0.29869967699050903,
-0.080961212515831,
-0.723082959651947,
0.90867209434509... |
9307 | are all white ionic crystalline solids that have high melting points. All the alkali metal halides are soluble in water except for lithium fluoride (LiF), which is insoluble in water due to its very high lattice enthalpy. The high lattice enthalpy of lithium fluoride is due to the small sizes of the Li and F ions, causing the electrostatic interactions between them to be strong: a similar effect occurs for magnesium fluoride, consistent with the diagonal relationship between lithium and magnesium. The alkali metals also react similarly with hydrogen to form ionic alkali metal hydrides, where the hydride anion acts | "Alkali metal" | [
-0.2282084822654724,
0.6656948924064636,
0.5103293061256409,
-0.09944894164800644,
-0.43055155873298645,
0.07494617253541946,
0.12972915172576904,
-0.5172243714332581,
0.4464151859283447,
-0.19641195237636566,
-0.22939448058605194,
0.07921597361564636,
-0.6520217657089233,
0.49456065893173... |
9308 | as a pseudohalide: these are often used as reducing agents, producing hydrides, complex metal hydrides, or hydrogen gas. Other pseudohalides are also known, notably the cyanides. These are isostructural to the respective halides except for lithium cyanide, indicating that the cyanide ions may rotate freely. Ternary alkali metal halide oxides, such as NaClO, KBrO (yellow), NaBrO, NaIO, and KBrO, are also known. The polyhalides are rather unstable, although those of rubidium and caesium are greatly stabilised by the feeble polarising power of these extremely large cations. Alkali metal cations do not usually form coordination complexes with simple Lewis bases due | "Alkali metal" | [
0.014999506063759327,
0.5503653883934021,
0.27575039863586426,
0.08162461966276169,
-0.519649088382721,
-0.1304824948310852,
0.14912119507789612,
-0.7176821231842041,
0.31130874156951904,
0.04517591372132301,
-0.4046202003955841,
-0.07146093994379044,
-0.7379971146583557,
0.732648074626922... |
9309 | to their low charge of just +1 and their relatively large size; thus the Li ion forms most complexes and the heavier alkali metal ions form less and less (though exceptions occur for weak complexes). Lithium in particular has a very rich coordination chemistry in which it exhibits coordination numbers from 1 to 12, although octahedral hexacoordination is its preferred mode. In aqueous solution, the alkali metal ions exist as octahedral hexahydrate complexes ([M(HO))]), with the exception of the lithium ion, which due to its small size forms tetrahedral tetrahydrate complexes ([Li(HO))]); the alkali metals form these complexes because their | "Alkali metal" | [
-0.2314814180135727,
0.7211697697639465,
0.3009580969810486,
-0.037110500037670135,
-0.4782958924770355,
0.22313280403614044,
0.10143978893756866,
-0.6865001320838928,
0.3144487142562866,
-0.11966664344072342,
-0.19455741345882416,
0.005700893700122833,
-0.6043535470962524,
0.5234981775283... |
9310 | ions are attracted by electrostatic forces of attraction to the polar water molecules. Because of this, anhydrous salts containing alkali metal cations are often used as desiccants. Alkali metals also readily form complexes with crown ethers (e.g. 12-crown-4 for Li, 15-crown-5 for Na, 18-crown-6 for K, and 21-crown-7 for Rb) and cryptands due to electrostatic attraction. The alkali metals dissolve slowly in liquid ammonia, forming ammoniacal solutions of solvated M and e, which react to form hydrogen gas and the alkali metal amide (MNH, where M represents an alkali metal): this was first noted by Humphry Davy in 1809 and | "Alkali metal" | [
-0.17819476127624512,
0.7850649952888489,
0.34565499424934387,
-0.16118289530277252,
-0.5844660401344299,
0.28279855847358704,
0.4120745062828064,
-0.6848003268241882,
0.34009820222854614,
-0.15097878873348236,
-0.1674169898033142,
-0.02154635265469551,
-0.615349292755127,
0.92723447084426... |
9311 | rediscovered by W. Weyl in 1864. The process may be speeded up by a catalyst. Similar solutions are formed by the heavy divalent alkaline earth metals calcium, strontium, barium, as well as the divalent lanthanides, europium and ytterbium. The amide salt is quite insoluble and readily precipitates out of solution, leaving intensely coloured ammonia solutions of the alkali metals. In 1907, Charles Krause identified the colour as being due to the presence of solvated electrons, which contribute to the high electrical conductivity of these solutions. At low concentrations (below 3 M), the solution is dark blue and has ten times | "Alkali metal" | [
-0.13026508688926697,
0.5247002243995667,
0.17002609372138977,
-0.28598031401634216,
-0.31173646450042725,
0.378621369600296,
0.3423956334590912,
-0.44757935404777527,
0.29311516880989075,
-0.4167717397212982,
-0.19198797643184662,
-0.11539222300052643,
-0.6937629580497742,
0.7586980462074... |
9312 | the conductivity of aqueous sodium chloride; at higher concentrations (above 3 M), the solution is copper-coloured and has approximately the conductivity of liquid metals like mercury. In addition to the alkali metal amide salt and solvated electrons, such ammonia solutions also contain the alkali metal cation (M), the neutral alkali metal atom (M), diatomic alkali metal molecules (M) and alkali metal anions (M). These are unstable and eventually become the more thermodynamically stable alkali metal amide and hydrogen gas. Solvated electrons are powerful reducing agents and are often used in chemical synthesis. Being the smallest alkali metal, lithium forms the | "Alkali metal" | [
-0.2517087161540985,
0.5473864078521729,
0.2496785819530487,
-0.17100736498832703,
-0.21287411451339722,
0.39345189929008484,
0.2259601652622223,
-0.6972213387489319,
0.40289968252182007,
-0.4281678795814514,
-0.21809962391853333,
0.13091377913951874,
-0.5859978199005127,
0.376152276992797... |
9313 | widest variety of and most stable organometallic compounds, which are bonded covalently. Organolithium compounds are electrically non-conducting volatile solids or liquids that melt at low temperatures, and tend to form oligomers with the structure (RLi) where R is the organic group. As the electropositive nature of lithium puts most of the charge density of the bond on the carbon atom, effectively creating a carbanion, organolithium compounds are extremely powerful bases and nucleophiles. For use as bases, butyllithiums are often used and are commercially available. An example of an organolithium compound is methyllithium ((CHLi)), which exists in tetrameric ("x" = 4, | "Alkali metal" | [
0.15643082559108734,
0.6254698634147644,
0.28652262687683105,
0.06915035843849182,
-0.3832174837589264,
-0.006180775351822376,
0.031061731278896332,
-0.5410998463630676,
0.5782016515731812,
-0.05841381475329399,
-0.2608381509780884,
-0.05646608769893646,
-0.6143028140068054,
0.617623865604... |
9314 | tetrahedral) and hexameric ("x" = 6, octahedral) forms. Organolithium compounds, especially "n"-butyllithium, are useful reagents in organic synthesis, as might be expected given lithium's diagonal relationship with magnesium, which plays an important role in the Grignard reaction. For example, alkyllithiums and aryllithiums may be used to synthesise aldehydes and ketones by reaction with metal carbonyls. The reaction with nickel tetracarbonyl, for example, proceeds through an unstable acyl nickel carbonyl complex which then undergoes electrophilic substitution to give the desired aldehyde (using H as the electrophile) or ketone (using an alkyl halide) product. Alkyllithiums and aryllithiums may also react with "N","N"-disubstituted | "Alkali metal" | [
0.07214248925447464,
0.47337087988853455,
0.21439410746097565,
0.0772312581539154,
-0.5147993564605713,
0.16325554251670837,
0.05941607058048248,
-0.6390808820724487,
0.4060860872268677,
-0.11158234626054764,
-0.28224509954452515,
0.09861096739768982,
-0.43484362959861755,
0.68317925930023... |
9315 | amides to give aldehydes and ketones, and symmetrical ketones by reacting with carbon monoxide. They thermally decompose to eliminate a β-hydrogen, producing alkenes and lithium hydride: another route is the reaction of ethers with alkyl- and aryllithiums that act as strong bases. In non-polar solvents, aryllithiums react as the carbanions they effectively are, turning carbon dioxide to aromatic carboxylic acids (ArCOH) and aryl ketones to tertiary carbinols (Ar'C(Ar)OH). Finally, they may be used to synthesise other organometallic compounds through metal-halogen exchange. Unlike the organolithium compounds, the organometallic compounds of the heavier alkali metals are predominantly ionic. The application of organosodium | "Alkali metal" | [
0.04346030578017235,
0.6968549489974976,
0.3273681402206421,
-0.08696195483207703,
-0.5550633668899536,
0.05866750329732895,
0.19908399879932404,
-0.7553622126579285,
0.45031633973121643,
-0.0792500451207161,
-0.2782568335533142,
0.1849900335073471,
-0.5479612350463867,
0.5864726901054382,... |
9316 | compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity. The principal organosodium compound of commercial importance is sodium cyclopentadienide. Sodium tetraphenylborate can also be classified as an organosodium compound since in the solid state sodium is bound to the aryl groups. Organometallic compounds of the higher alkali metals are even more reactive than organosodium compounds and of limited utility. A notable reagent is Schlosser's base, a mixture of "n"-butyllithium and potassium "tert"-butoxide. This reagent reacts with propene to form the compound allylpotassium (KCHCHCH). "cis"-2-Butene and "trans"-2-butene equilibrate | "Alkali metal" | [
0.0414595790207386,
0.37608763575553894,
0.35352808237075806,
-0.030253630131483078,
-0.6043432950973511,
-0.0713069811463356,
0.06232358142733574,
-0.5820576548576355,
0.4988451600074768,
-0.21053382754325867,
-0.33495333790779114,
0.09645349532365799,
-0.5725207924842834,
0.6755415201187... |
9317 | when in contact with alkali metals. Whereas isomerisation is fast with lithium and sodium, it is slow with the heavier alkali metals. The heavier alkali metals also favour the sterically congested conformation. Several crystal structures of organopotassium compounds have been reported, establishing that they, like the sodium compounds, are polymeric. Organosodium, organopotassium, organorubidium and organocaesium compounds are all mostly ionic and are insoluble (or nearly so) in nonpolar solvents. Alkyl and aryl derivatives of sodium and potassium tend to react with air. They cause the cleavage of ethers, generating alkoxides. Unlike alkyllithium compounds, alkylsodiums and alkylpotassiums cannot be made by | "Alkali metal" | [
-0.06624782830476761,
0.5667102932929993,
0.353099524974823,
-0.15005360543727875,
-0.45214173197746277,
0.055918969213962555,
0.16675768792629242,
-0.6433896422386169,
0.2746375501155853,
-0.2837330996990204,
-0.32977011799812317,
0.07447350025177002,
-0.7089720368385315,
0.60922193527221... |
9318 | reacting the metals with alkyl halides because Wurtz coupling occurs: As such, they have to be made by reacting alkylmercury compounds with sodium or potassium metal in inert hydrocarbon solvents. While methylsodium forms tetramers like methyllithium, methylpotassium is more ionic and has the nickel arsenide structure with discrete methyl anions and potassium cations. The alkali metals and their hydrides react with acidic hydrocarbons, for example cyclopentadienes and terminal alkynes, to give salts. Liquid ammonia, ether, or hydrocarbon solvents are used, the most common of which being tetrahydrofuran. The most important of these compounds is sodium cyclopentadienide, NaCH, an important precursor | "Alkali metal" | [
-0.009572691284120083,
0.6306068897247314,
0.26664096117019653,
0.07422936707735062,
-0.6121202707290649,
0.0028888925444334745,
0.15832354128360748,
-0.5966994762420654,
0.5276508927345276,
-0.32927125692367554,
-0.25043830275535583,
0.06093159690499306,
-0.5633081793785095,
0.77313667535... |
9319 | to many transition metal cyclopentadienyl derivatives. Similarly, the alkali metals react with cyclooctatetraene in tetrahydrofuran to give alkali metal cyclooctatetraenides; for example, dipotassium cyclooctatetraenide (KCH) is an important precursor to many metal cyclooctatetraenyl derivatives, such as uranocene. The large and very weakly polarising alkali metal cations can stabilise large, aromatic, polarisable radical anions, such as the dark-green sodium naphthalenide, Na[CH•], a strong reducing agent. Although francium is the heaviest alkali metal that has been discovered, there has been some theoretical work predicting the physical and chemical characteristics of the hypothetical heavier alkali metals. Being the first period 8 element, the | "Alkali metal" | [
-0.06264765560626984,
0.420535147190094,
0.3589768409729004,
0.024464266374707222,
-0.6802842020988464,
0.16146665811538696,
-0.0405145138502121,
-0.6353506445884705,
0.35708853602409363,
-0.23362304270267487,
-0.3231833875179291,
0.16598720848560333,
-0.6201947331428528,
0.512193977832794... |
9320 | undiscovered element ununennium (element 119) is predicted to be the next alkali metal after francium and behave much like their lighter congeners; however, it is also predicted to differ from the lighter alkali metals in some properties. Its chemistry is predicted to be closer to that of potassium or rubidium instead of caesium or francium. This is unusual as periodic trends, ignoring relativistic effects would predict ununennium to be even more reactive than caesium and francium. This lowered reactivity is due to the relativistic stabilisation of ununennium's valence electron, increasing ununennium's first ionisation energy and decreasing the metallic and ionic | "Alkali metal" | [
-0.05653144419193268,
0.07656348496675491,
0.29255956411361694,
0.056129321455955505,
-0.5643512606620789,
0.0293781328946352,
0.270411878824234,
-0.48412445187568665,
0.5439527034759521,
-0.28115707635879517,
-0.1891956925392151,
0.15880994498729706,
-0.5245563387870789,
0.433365136384964... |
9321 | radii; this effect is already seen for francium. This assumes that ununennium will behave chemically as an alkali metal, which, although likely, may not be true due to relativistic effects. The relativistic stabilisation of the 8s orbital also increases ununennium's electron affinity far beyond that of caesium and francium; indeed, ununennium is expected to have an electron affinity higher than all the alkali metals lighter than it. Relativistic effects also cause a very large drop in the polarisability of ununennium. On the other hand, ununennium is predicted to continue the trend of melting points decreasing going down the group, being | "Alkali metal" | [
-0.10526928305625916,
0.18351109325885773,
0.3662106692790985,
-0.13484792411327362,
-0.547167181968689,
-0.0032327163498848677,
0.38299065828323364,
-0.6215788125991821,
0.31825241446495056,
-0.33252134919166565,
-0.12998992204666138,
0.06963550299406052,
-0.4779796600341797,
0.4723525345... |
9322 | expected to have a melting point between 0 °C and 30 °C. The stabilisation of ununennium's valence electron and thus the contraction of the 8s orbital cause its atomic radius to be lowered to 240 pm, very close to that of rubidium (247 pm), so that the chemistry of ununennium in the +1 oxidation state should be more similar to the chemistry of rubidium than to that of francium. On the other hand, the ionic radius of the Uue ion is predicted to be larger than that of Rb, because the 7p orbitals are destabilised and are thus larger than | "Alkali metal" | [
-0.1645551174879074,
0.28784143924713135,
0.4116041958332062,
-0.2243916541337967,
-0.43098312616348267,
0.07761123776435852,
0.41572707891464233,
-0.707272469997406,
0.4663272202014923,
-0.003940399270504713,
0.11515258997678757,
0.05568336322903633,
-0.5095070600509644,
0.571837663650512... |
9323 | the p-orbitals of the lower shells. Ununennium may also show the +3 oxidation state, which is not seen in any other alkali metal, in addition to the +1 oxidation state that is characteristic of the other alkali metals and is also the main oxidation state of all the known alkali metals: this is because of the destabilisation and expansion of the 7p spinor, causing its outermost electrons to have a lower ionisation energy than what would otherwise be expected. Indeed, many ununennium compounds are expected to have a large covalent character, due to the involvement of the 7p electrons in | "Alkali metal" | [
-0.18063688278198242,
0.19430342316627502,
0.17312142252922058,
-0.1989738941192627,
-0.4168451130390167,
0.05571218580007553,
0.4046459197998047,
-0.5401902198791504,
0.31924501061439514,
-0.27120015025138855,
-0.17762982845306396,
0.16030068695545197,
-0.596160352230072,
0.59627407789230... |
9324 | the bonding. Not as much work has been done predicting the properties of the alkali metals beyond ununennium. Although a simple extrapolation of the periodic table would put element 169, unhexennium, under ununennium, Dirac-Fock calculations predict that the next alkali metal after ununennium may actually be element 165, unhexpentium, which is predicted to have the electron configuration [Og] 5g 6f 7d 8s 8p 9s. Furthermore, this element would be intermediate in properties between an alkali metal and a group 11 element, and while its physical and atomic properties would be closer to the former, its chemistry may be closer to | "Alkali metal" | [
0.00018919832655228674,
0.40236788988113403,
0.31665006279945374,
-0.25465744733810425,
-0.518057107925415,
0.13605938851833344,
0.23310382664203644,
-0.6742766499519348,
0.40033042430877686,
-0.12379773706197739,
-0.11864883452653885,
0.12517200410366058,
-0.5962224006652832,
0.6346477270... |
9325 | that of the latter. Further calculations show that unhexpentium would follow the trend of increasing ionisation energy beyond caesium, having an ionisation energy comparable to that of sodium, and that it should also continue the trend of decreasing atomic radii beyond caesium, having an atomic radius comparable to that of potassium. However, the 7d electrons of unhexpentium may also be able to participate in chemical reactions along with the 9s electron, possibly allowing oxidation states beyond +1, whence the likely transition metal behaviour of unhexpentium. Due to the alkali and alkaline earth metals both being s-block elements, these predictions for | "Alkali metal" | [
0.09543956816196442,
0.4050743579864502,
0.18692372739315033,
-0.1594504863023758,
-0.4564715325832367,
-0.0007233885698951781,
0.4413246214389801,
-0.6526446342468262,
0.4601875841617584,
-0.3954458236694336,
-0.10571540147066116,
0.09407267719507217,
-0.6345846056938171,
0.58178985118865... |
9326 | the trends and properties of ununennium and unhexpentium also mostly hold quite similarly for the corresponding alkaline earth metals unbinilium (Ubn) and unhexhexium (Uhh). The probable properties of further alkali metals beyond unhexpentium have not been explored yet as of 2015; in fact, it is suspected that they may not be able to exist. In periods 8 and above of the periodic table, relativistic and shell-structure effects become so strong that extrapolations from lighter congeners become completely inaccurate. In addition, the relativistic and shell-structure effects (which stabilise the s-orbitals and destabilise and expand the d-, f-, and g-orbitals of higher | "Alkali metal" | [
0.004481257870793343,
0.5383672118186951,
0.11219679564237595,
-0.13914138078689575,
-0.45936262607574463,
-0.09989466518163681,
0.38138046860694885,
-0.39101657271385193,
0.45243942737579346,
-0.32722702622413635,
-0.04033631086349487,
-0.024942321702837944,
-0.5088582038879395,
0.7200482... |
9327 | shells) have opposite effects, causing even larger difference between relativistic and non-relativistic calculations of the properties of elements with such high atomic numbers. Interest in the chemical properties of ununennium and unhexpentium stems from the fact that both elements are located close to the expected locations of islands of stabilities, centered at elements 122 (Ubb) and 164 (Uhq). Many other substances are similar to the alkali metals in their tendency to form monopositive cations. Analogously to the pseudohalogens, they have sometimes been called "pseudo-alkali metals". These substances include some elements and many more polyatomic ions; the polyatomic ions are especially | "Alkali metal" | [
0.3035607933998108,
0.5714125037193298,
0.03326252102851868,
-0.06350082904100418,
-0.30098438262939453,
0.13401727378368378,
0.2483290433883667,
-0.522031843662262,
0.38750404119491577,
-0.1950109899044037,
-0.03048250637948513,
0.0025368784554302692,
-0.6144788861274719,
0.59369462728500... |
9328 | similar to the alkali metals in their large size and weak polarising power. The element hydrogen, with one electron per neutral atom, is usually placed at the top of Group 1 of the periodic table for convenience, but hydrogen is not normally considered to be an alkali metal; when it is considered to be an alkali metal, it is because of its atomic properties and not its chemical properties. Under typical conditions, pure hydrogen exists as a diatomic gas consisting of two atoms per molecule (H); however, the alkali metals only form diatomic molecules (such as dilithium, Li) at high | "Alkali metal" | [
0.01223260723054409,
0.5468536615371704,
-0.0014328889083117247,
-0.03736640512943268,
-0.6051648259162903,
-0.07076666504144669,
0.18702194094657898,
-0.6595295071601868,
0.40638473629951477,
-0.49914708733558655,
-0.21825769543647766,
-0.2146463692188263,
-0.8006435632705688,
0.565479159... |
9329 | temperatures, when they are in the gaseous state. Hydrogen, like the alkali metals, has one valence electron and reacts easily with the halogens, but the similarities end there because of the small size of a bare proton H compared to the alkali metal cations. Its placement above lithium is primarily due to its electron configuration. It is sometimes placed above carbon due to their similar electronegativities or fluorine due to their similar chemical properties. The first ionisation energy of hydrogen (1312.0 kJ/mol) is much higher than that of the alkali metals. As only one additional electron is required to fill | "Alkali metal" | [
0.001546303043141961,
0.5349622964859009,
0.056594595313072205,
-0.17586569488048553,
-0.3774082064628601,
0.04116993397474289,
0.05257411673665047,
-0.7294936180114746,
0.39464861154556274,
-0.41061919927597046,
-0.15137673914432526,
-0.12364832311868668,
-0.4593760371208191,
0.4146631658... |
9330 | in the outermost shell of the hydrogen atom, hydrogen often behaves like a halogen, forming the negative hydride ion, and is very occasionally considered to be a halogen on that basis. (The alkali metals can also form negative ions, known as alkalides, but these are little more than laboratory curiosities, being unstable.) An argument against this placement is that formation of hydride from hydrogen is endothermic, unlike the exothermic formation of halides from halogens. The radius of the H anion also does not fit the trend of increasing size going down the halogens: indeed, H is very diffuse because its | "Alkali metal" | [
-0.04172173887491226,
0.702592134475708,
0.2679375410079956,
-0.0916733592748642,
-0.5236744284629822,
-0.3764524459838867,
0.2407747060060501,
-0.83592689037323,
0.4680115878582001,
-0.3888173997402191,
-0.21665164828300476,
-0.17830021679401398,
-0.6807636618614197,
0.6166926622390747,
... |
9331 | single proton cannot easily control both electrons. It was expected for some time that liquid hydrogen would show metallic properties; while this has been shown to not be the case, under extremely high pressures, such as those found at the cores of Jupiter and Saturn, hydrogen does become metallic and behaves like an alkali metal; in this phase, it is known as metallic hydrogen. The electrical resistivity of liquid metallic hydrogen at 3000 K is approximately equal to that of liquid rubidium and caesium at 2000 K at the respective pressures when they undergo a nonmetal-to-metal transition. The 1s electron | "Alkali metal" | [
0.001223401864990592,
0.4743110239505768,
0.0648711547255516,
-0.06924416124820709,
-0.4208974540233612,
0.03034541942179203,
0.3395884335041046,
-0.721693754196167,
0.39474964141845703,
-0.19931264221668243,
0.003202037652954459,
-0.12038435786962509,
-0.6580981612205505,
0.53371322154998... |
9332 | configuration of hydrogen, while superficially similar to that of the alkali metals (ns), is unique because there is no 1p subshell. Hence it can lose an electron to form the hydron H, or gain one to form the hydride ion H. In the former case it resembles superficially the alkali metals; in the latter case, the halogens, but the differences due to the lack of a 1p subshell are important enough that neither group fits the properties of hydrogen well. Group 14 is also a good fit in terms of thermodynamic properties such as ionisation energy and electron affinity, but | "Alkali metal" | [
0.003361538052558899,
0.48383772373199463,
0.3039640784263611,
0.07060591876506805,
-0.6058924794197083,
-0.17350836098194122,
0.09376189857721329,
-0.8249496817588806,
0.3150996267795563,
-0.32433632016181946,
-0.19129154086112976,
-0.1879405677318573,
-0.695501446723938,
0.37319517135620... |
9333 | makes chemical nonsense because hydrogen cannot be tetravalent. Thus none of the three placements are entirely satisfactory, although group 1 is the most common placement (if one is chosen) because the hydron is by far the most important of all monatomic hydrogen species, being the foundation of acid-base chemistry. As an example of hydrogen's unorthodox properties stemming from its unusual electron configuration and small size, the hydrogen ion is very small (radius around 150 fm compared to the 50–220 pm size of most other atoms and ions) and so is nonexistent in condensed systems other than in association with other | "Alkali metal" | [
-0.058062415570020676,
0.6426495909690857,
0.16420581936836243,
-0.1198156476020813,
-0.5432605743408203,
-0.027246184647083282,
0.15460780262947083,
-0.9280485510826111,
0.5104655027389526,
-0.21726857125759125,
-0.020792827010154724,
-0.10170701891183853,
-0.5830661654472351,
0.593332052... |
9334 | atoms or molecules. Indeed, transferring of protons between chemicals is the basis of acid-base chemistry. Also unique is hydrogen's ability to form hydrogen bonds, which are an effect of charge-transfer, electrostatic, and electron correlative contributing phenomena. While analogous lithium bonds are also known, they are mostly electrostatic. Nevertheless, hydrogen can take on the same structural role as the alkali metals in some molecular crystals, and has a close relationship with the lightest alkali metals (especially lithium). The ammonium ion () has very similar properties to the heavier alkali metals, acting as an alkali metal intermediate between potassium and rubidium, and | "Alkali metal" | [
-0.007015201263129711,
0.6476702094078064,
0.01616164855659008,
-0.02681957371532917,
-0.450339674949646,
-0.10126922279596329,
0.1710813194513321,
-0.6914995908737183,
0.42488133907318115,
-0.44024619460105896,
-0.04265989735722542,
-0.06119871884584427,
-0.543486475944519,
0.511960327625... |
9335 | is often considered a close relative. For example, most alkali metal salts are soluble in water, a property which ammonium salts share. Ammonium is expected to behave stably as a metal ( ions in a sea of delocalised electrons) at very high pressures (though less than the typical pressure where transitions from insulating to metallic behaviour occur around, 100 GPa), and could possibly occur inside the ice giants Uranus and Neptune, which may have significant impacts on their interior magnetic fields. It has been estimated that the transition from a mixture of ammonia and dihydrogen molecules to metallic ammonium may | "Alkali metal" | [
-0.13155271112918854,
0.48098278045654297,
0.2749626338481903,
-0.07342731207609177,
-0.35621964931488037,
-0.11106609553098679,
0.4003649652004242,
-0.5326097011566162,
0.2137858122587204,
-0.23795805871486664,
-0.07340547442436218,
-0.1919173300266266,
-0.6798304319381714,
0.497223854064... |
9336 | occur at pressures just below 25 GPa. Under standard conditions, ammonium can form a metallic amalgam with mercury. Other "pseudo-alkali metals" include the alkylammonium cations, in which some of the hydrogen atoms in the ammonium cation are replaced by alkyl or aryl groups. In particular, the quaternary ammonium cations () are very useful since they are permanently charged, and they are often used as an alternative to the expensive Cs to stabilise very large and very easily polarisable anions such as . Tetraalkylammonium hydroxides, like alkali metal hydroxides, are very strong bases that react with atmospheric carbon dioxide to form | "Alkali metal" | [
0.1711244434118271,
0.7023600935935974,
0.20674622058868408,
0.13682448863983154,
-0.37696343660354614,
-0.03549257665872574,
0.29680556058883667,
-0.6712222099304199,
0.4181091785430908,
-0.23001030087471008,
-0.26587140560150146,
0.02419203147292137,
-0.6016555428504944,
0.54692125320434... |
9337 | carbonates. Furthermore, the nitrogen atom may be replaced by a phosphorus, arsenic, or antimony atom (the heavier nonmetallic pnictogens), creating a phosphonium () or arsonium () cation that can itself be substituted similarly; while stibonium () itself is not known, some of its organic derivatives are characterised. Cobaltocene, Co(CH), is a metallocene, the cobalt analogue of ferrocene. It is a dark purple solid. Cobaltocene has 19 valence electrons, one more than usually found in organotransition metal complexes, such as its very stable relative, ferrocene, in accordance with the 18-electron rule. This additional electron occupies an orbital that is antibonding with | "Alkali metal" | [
0.11915668100118637,
0.4667549431324005,
0.26069384813308716,
0.062381938099861145,
-0.38509488105773926,
0.15162809193134308,
-0.16398760676383972,
-0.30664578080177307,
0.32836219668388367,
-0.07307218015193939,
-0.22831451892852783,
0.1068209633231163,
-0.5804150700569153,
0.64053934812... |
9338 | respect to the Co–C bonds. Consequently, many chemical reactions of Co(CH) are characterized by its tendency to lose this "extra" electron, yielding a very stable 18-electron cation known as cobaltocenium. Many cobaltocenium salts coprecipitate with caesium salts, and cobaltocenium hydroxide is a strong base that absorbs atmospheric carbon dioxide to form cobaltocenium carbonate. Like the alkali metals, cobaltocene is a strong reducing agent, and decamethylcobaltocene is stronger still due to the combined inductive effect of the ten methyl groups. Cobalt may be substituted by its heavier congener rhodium to give rhodocene, an even stronger reducing agent. Iridocene (involving iridium) would | "Alkali metal" | [
0.04850481450557709,
0.5026361346244812,
0.35384368896484375,
-0.020570697262883186,
-0.399120569229126,
0.020938066765666008,
-0.056790679693222046,
-0.5615395903587341,
0.4023781716823578,
-0.13829995691776276,
-0.24530906975269318,
0.17893891036510468,
-0.6110601425170898,
0.67902261018... |
9339 | presumably be still more potent, but is not very well-studied due to its instability. Thallium is the heaviest stable element in group 13 of the periodic table. At the bottom of the periodic table, the inert pair effect is quite strong, because of the relativistic stabilisation of the 6s orbital and the decreasing bond energy as the atoms increase in size so that the amount of energy released in forming two more bonds is not worth the high ionisation energies of the 6s electrons. It displays the +1 oxidation state that all the known alkali metals display, and thallium compounds | "Alkali metal" | [
-0.12523801624774933,
0.4734020233154297,
-0.003099903929978609,
-0.11659201234579086,
-0.45917269587516785,
-0.1650385707616806,
0.018482118844985962,
-0.6257918477058411,
0.4117012023925781,
-0.2461467683315277,
-0.14440564811229706,
-0.11673199385404587,
-0.7814605832099915,
0.488238900... |
9340 | with thallium in its +1 oxidation state closely resemble the corresponding potassium or silver compounds stoichiometrically due to the similar ionic radii of the Tl (164 pm), K (152 pm) and Ag (129 pm) ions. It was sometimes considered an alkali metal in continental Europe (but not in England) in the years immediately following its discovery, and was placed just after caesium as the sixth alkali metal in Dmitri Mendeleev's 1869 periodic table and Julius Lothar Meyer's 1868 periodic table. (Mendeleev's 1871 periodic table and Meyer's 1870 periodic table put thallium in its current position in the boron group and | "Alkali metal" | [
-0.1513252854347229,
0.4006054103374481,
0.08802294731140137,
-0.22301912307739258,
-0.7502278685569763,
0.3950124979019165,
0.3390352427959442,
-0.43474066257476807,
0.43228811025619507,
0.019796229898929596,
-0.08731619268655777,
-0.21783876419067383,
-0.5232816934585571,
1.0202518701553... |
9341 | left the space below caesium blank.) However, thallium also displays the oxidation state +3, which no known alkali metal displays (although ununennium, the undiscovered seventh alkali metal, is predicted to possibly display the +3 oxidation state). The sixth alkali metal is now considered to be francium. While Tl is stabilised by the inert pair effect, this inert pair of 6s electrons is still able to participate chemically, so that these electrons are stereochemically active in aqueous solution. Additionally, the thallium halides (except TlF) are quite insoluble in water, and TlI has an unusual structure because of the presence of the | "Alkali metal" | [
0.23428606986999512,
0.13282510638237,
0.41049832105636597,
0.022520286962389946,
-0.6014554500579834,
-0.0014849364524707198,
0.2099090963602066,
-0.5724182724952698,
0.38050082325935364,
-0.3017536401748657,
-0.21830493211746216,
0.08413925021886826,
-0.6419044137001038,
0.64700013399124... |
9342 | stereochemically active inert pair in thallium. The group 11 metals (or coinage metals), copper, silver, and gold, are typically categorised as transition metals given they can form ions with incomplete d-shells. Physically, they have the relatively low melting points and high electronegativity values associated with post-transition metals. "The filled "d" subshell and free "s" electron of Cu, Ag, and Au contribute to their high electrical and thermal conductivity. Transition metals to the left of group 11 experience interactions between "s" electrons and the partially filled "d" subshell that lower electron mobility." Chemically, the group 11 metals behave like main-group metals | "Alkali metal" | [
0.18535591661930084,
0.6155428886413574,
-0.11264971643686295,
0.2085701823234558,
-0.3894607424736023,
0.035338714718818665,
0.2365785837173462,
-0.2833966612815857,
0.5420794486999512,
-0.30316075682640076,
-0.20307837426662445,
-0.020772363990545273,
-0.5262959599494934,
0.5310590863227... |
9343 | in their +1 valence states, and are hence somewhat related to the alkali metals: this is one reason for their previously being labelled as "group IB", paralleling the alkali metals' "group IA". They are occasionally classified as post-transition metals. Their spectra are analogous to those of the alkali metals. Their monopositive ions are paramagnetic and contribute no colour to their salts, like those of the alkali metals. In Mendeleev's 1871 periodic table, copper, silver, and gold are listed twice, once under group VIII (with the iron triad and platinum group metals), and once under group IB. Group IB was nonetheless | "Alkali metal" | [
0.11492588371038437,
0.5821494460105896,
-0.30107372999191284,
-0.08062823861837387,
-0.44203630089759827,
0.17887279391288757,
0.4039328396320343,
-0.3653968870639801,
0.14116960763931274,
-0.26309382915496826,
-0.09491121768951416,
-0.09804074466228485,
-0.6335052847862244,
0.98618000745... |
9344 | parenthesised to note that it was tentative. Mendeleev's main criterion for group assignment was the maximum oxidation state of an element: on that basis, the group 11 elements could not be classified in group IB, due to the existence of copper(II) and gold(III) compounds being known at that time. However, eliminating group IB would make group I the only main group (group VIII was labelled a transition group) to lack an A–B bifurcation. Soon afterward, a majority of chemists chose to classify these elements in group IB and remove them from group VIII for the resulting symmetry: this was the | "Alkali metal" | [
-0.03208383545279503,
0.5686666369438171,
-0.24860846996307373,
-0.13004423677921295,
-0.5689677596092224,
-0.0071439072489738464,
0.344384104013443,
-0.786501407623291,
0.4842109978199005,
-0.00032537936931475997,
0.0734686627984047,
-0.10471254587173462,
-0.7597028017044067,
0.7471653223... |
9345 | predominant classification until the rise of the modern medium-long 18-column periodic table, which separated the alkali metals and group 11 metals. The coinage metals were traditionally regarded as a subdivision of the alkali metal group, due to them sharing the characteristic s electron configuration of the alkali metals (group 1: ps; group 11: ds). However, the similarities are largely confined to the stoichiometries of the +1 compounds of both groups, and not their chemical properties. This stems from the filled d subshell providing a much weaker shielding effect on the outermost s electron than the filled p subshell, so that | "Alkali metal" | [
0.3126983046531677,
0.2993758022785187,
-0.21619679033756256,
0.0834013819694519,
-0.7591622471809387,
0.1743387132883072,
0.3086712658405304,
-0.33482757210731506,
0.29203328490257263,
-0.3293662667274475,
-0.19145390391349792,
-0.2647462487220764,
-0.5167195796966553,
0.7383869886398315,... |
9346 | the coinage metals have much higher first ionisation energies and smaller ionic radii than do the corresponding alkali metals. Furthermore, they have higher melting points, hardnesses, and densities, and lower reactivities and solubilities in liquid ammonia, as well as having more covalent character in their compounds. Finally, the alkali metals are at the top of the electrochemical series, whereas the coinage metals are almost at the very bottom. The coinage metals' filled d shell is much more easily disrupted than the alkali metals' filled p shell, so that the second and third ionisation energies are lower, enabling higher oxidation states | "Alkali metal" | [
-0.16894769668579102,
0.43135544657707214,
-0.11927109956741333,
0.18021491169929504,
-0.4473613500595093,
0.16410918533802032,
0.018256640061736107,
-0.23854361474514008,
0.30310168862342834,
-0.4873812198638916,
-0.20946481823921204,
0.026512086391448975,
-0.5528404116630554,
0.598960518... |
9347 | than +1 and a richer coordination chemistry, thus giving the group 11 metals clear transition metal character. Particularly noteworthy is gold forming ionic compounds with rubidium and caesium, in which it forms the auride ion (Au) which also occurs in solvated form in liquid ammonia solution: here gold behaves as a pseudohalogen because its 5d6s configuration has one electron less than the quasi-closed shell 5d6s configuration of mercury. The production of pure alkali metals is somewhat complicated due to their extreme reactivity with commonly used substances, such as water. From their silicate ores, all the stable alkali metals may be | "Alkali metal" | [
-0.052805859595537186,
0.6721804141998291,
0.13961614668369293,
-0.11489057540893555,
-0.44414079189300537,
0.006846186239272356,
0.31154003739356995,
-0.5816347599029541,
0.38008028268814087,
-0.13967254757881165,
-0.12103010714054108,
0.20299404859542847,
-0.6018134951591492,
0.603371381... |
9348 | obtained the same way: sulfuric acid is first used to dissolve the desired alkali metal ion and aluminium(III) ions from the ore (leaching), whereupon basic precipitation removes aluminium ions from the mixture by precipitating it as the hydroxide. The remaining insoluble alkali metal carbonate is then precipitated selectively; the salt is then dissolved in hydrochloric acid to produce the chloride. The result is then left to evaporate and the alkali metal can then be isolated. Lithium and sodium are typically isolated through electrolysis from their liquid chlorides, with calcium chloride typically added to lower the melting point of the mixture. | "Alkali metal" | [
-0.04514862224459648,
0.8007240295410156,
0.11228229105472565,
-0.20464681088924408,
-0.20242436230182648,
0.3253100514411926,
0.16107799112796783,
-0.5558759570121765,
0.4340980648994446,
0.01607595942914486,
-0.26940569281578064,
0.21356454491615295,
-0.6061420440673828,
0.68306434154510... |
9349 | The heavier alkali metals, however, is more typically isolated in a different way, where a reducing agent (typically sodium for potassium and magnesium or calcium for the heaviest alkali metals) is used to reduce the alkali metal chloride. The liquid or gaseous product (the alkali metal) then undergoes fractional distillation for purification. Most routes to the pure alkali metals require the use of electrolysis due to their high reactivity; one of the few which does not is the pyrolysis of the corresponding alkali metal azide, which yields the metal for sodium, potassium, rubidium, and caesium and the nitride for lithium. | "Alkali metal" | [
-0.03685406595468521,
0.5737646222114563,
0.0005086010787636042,
-0.03253705054521561,
-0.1749783158302307,
0.08689113706350327,
0.11554303020238876,
-0.4958593249320984,
0.4175511598587036,
-0.08743733167648315,
-0.3204859495162964,
0.3433760404586792,
-0.5663069486618042,
0.6313579678535... |
9350 | Lithium salts have to be extracted from the water of mineral springs, brine pools, and brine deposits. The metal is produced electrolytically from a mixture of fused lithium chloride and potassium chloride. Sodium occurs mostly in seawater and dried seabed, but is now produced through electrolysis of sodium chloride by lowering the melting point of the substance to below 700 °C through the use of a Downs cell. Extremely pure sodium can be produced through the thermal decomposition of sodium azide. Potassium occurs in many minerals, such as sylvite (potassium chloride). Previously, potassium was generally made from the electrolysis of | "Alkali metal" | [
-0.16454951465129852,
0.5141858458518982,
-0.03408782184123993,
-0.029763327911496162,
-0.039454806596040726,
0.23194967210292816,
0.24894557893276215,
-0.35095342993736267,
0.4625113904476166,
0.014484905637800694,
-0.07257861644029617,
0.16009216010570526,
-0.49277424812316895,
0.4737562... |
9351 | potassium chloride or potassium hydroxide, found extensively in places such as Canada, Russia, Belarus, Germany, Israel, United States, and Jordan, in a method similar to how sodium was produced in the late 1800s and early 1900s. It can also be produced from seawater. However, these methods are problematic because the potassium metal tends to dissolve in its molten chloride and vaporises significantly at the operating temperatures, potentially forming the explosive superoxide. As a result, pure potassium metal is now produced by reducing molten potassium chloride with sodium metal at 850 °C. Although sodium is less reactive than potassium, this process | "Alkali metal" | [
0.11419162899255753,
0.5472181439399719,
-0.23060981929302216,
-0.04572134464979172,
-0.23107460141181946,
0.05040186271071434,
0.2314343899488449,
-0.2665380537509918,
0.2599463164806366,
-0.24403116106987,
-0.06391005218029022,
-0.1743367463350296,
-0.5653291344642639,
0.6727007627487183... |
9352 | works because at such high temperatures potassium is more volatile than sodium and can easily be distilled off, so that the equilibrium shifts towards the right to produce more potassium gas and proceeds almost to completion. For several years in the 1950s and 1960s, a by-product of the potassium production called Alkarb was a main source for rubidium. Alkarb contained 21% rubidium while the rest was potassium and a small fraction of caesium. Today the largest producers of caesium, for example the Tanco Mine in Manitoba, Canada, produce rubidium as by-product from pollucite. Today, a common method for separating rubidium | "Alkali metal" | [
-0.07278424501419067,
0.5020202398300171,
-0.0826369971036911,
0.1411067247390747,
-0.5389215350151062,
-0.10441847145557404,
0.18887102603912354,
-0.24709588289260864,
0.5290513634681702,
0.09633251279592514,
0.10626670718193054,
-0.04386066645383835,
-0.5080209374427795,
0.59097898006439... |
9353 | from potassium and caesium is the fractional crystallisation of a rubidium and caesium alum (Cs,Rb)Al(SO)·12HO, which yields pure rubidium alum after approximately 30 recrystallisations. The limited applications and the lack of a mineral rich in rubidium limit the production of rubidium compounds to 2 to 4 tonnes per year. Caesium, however, is not produced from the above reaction. Instead, the mining of pollucite ore is the main method of obtaining pure caesium, extracted from the ore mainly by three methods: acid digestion, alkaline decomposition, and direct reduction. Both metals are produced as by-products of lithium production: after 1958, when interest | "Alkali metal" | [
0.06923747062683105,
0.566980242729187,
0.06379393488168716,
-0.15702120959758759,
-0.5088231563568115,
0.1112935021519661,
0.2232251614332199,
-0.34751543402671814,
0.3995676636695862,
0.44985270500183105,
0.10437177866697311,
0.1904280036687851,
-0.4093153476715088,
0.7306009531021118,
... |
9354 | in lithium's thermonuclear properties increased sharply, the production of rubidium and caesium also increased correspondingly. Pure rubidium and caesium metals are produced by reducing their chlorides with calcium metal at 750 °C and low pressure. As a result of its extreme rarity in nature, most francium is synthesised in the nuclear reaction Au + O → Fr + 5 n, yielding francium-209, francium-210, and francium-211. The greatest quantity of francium ever assembled to date is about 300,000 neutral atoms, which were synthesised using the nuclear reaction given above. When the only natural isotope francium-223 is specifically required, it is produced | "Alkali metal" | [
-0.08060963451862335,
0.5252376198768616,
-0.0625097006559372,
-0.09032483398914337,
-0.3122340142726898,
0.29580458998680115,
0.24178990721702576,
-0.38790348172187805,
0.37592628598213196,
0.09948375076055527,
0.0010471164714545012,
0.2368326485157013,
-0.5198377966880798,
0.519758343696... |
9355 | as the alpha daughter of actinium-227, itself produced synthetically from the neutron irradiation of natural radium-226, one of the daughters of natural uranium-238. Lithium, sodium, and potassium have many applications, while rubidium and caesium are very useful in academic contexts but do not have many applications yet. Lithium is often used in lithium-ion batteries, and lithium oxide can help process silica. Lithium stearate is a thickener and can be used to make lubricating greases; it is produced from lithium hydroxide, which is also used to absorb carbon dioxide in space capsules and submarines. Lithium chloride is used as a brazing | "Alkali metal" | [
0.2707952558994293,
0.6016635894775391,
0.08054347336292267,
-0.006102960556745529,
-0.1147366538643837,
0.02329244464635849,
-0.16910764575004578,
-0.3530983030796051,
0.2922024428844452,
-0.24187801778316498,
-0.03373211622238159,
0.32410287857055664,
-0.4189763069152832,
0.5148947834968... |
9356 | alloy for aluminium parts. Metallic lithium is used in alloys with magnesium and aluminium to give very tough and light alloys. Sodium compounds have many applications, the most well-known being sodium chloride as table salt. Sodium salts of fatty acids are used as soap. Pure sodium metal also has many applications, including use in sodium-vapour lamps, which produce very efficient light compared to other types of lighting, and can help smooth the surface of other metals. Being a strong reducing agent, it is often used to reduce many other metals, such as titanium and zirconium, from their chlorides. Furthermore, it | "Alkali metal" | [
0.02499479241669178,
0.5437754988670349,
0.029788881540298462,
-0.026846187189221382,
-0.38262176513671875,
0.060687873512506485,
0.3163197636604309,
-0.32364097237586975,
0.355831116437912,
-0.47398048639297485,
0.051872748881578445,
0.11934918910264969,
-0.3210153579711914,
0.50793206691... |
9357 | is very useful as a heat-exchange liquid in fast breeder nuclear reactors due to its low melting point, viscosity, and cross-section towards neutron absorption. Potassium compounds are often used as fertilisers as potassium is an important element for plant nutrition. Potassium hydroxide is a very strong base, and is used to control the pH of various substances. Potassium nitrate and potassium permanganate are often used as powerful oxidising agents. Potassium superoxide is used in breathing masks, as it reacts with carbon dioxide to give potassium carbonate and oxygen gas. Pure potassium metal is not often used, but its alloys with | "Alkali metal" | [
0.09796828031539917,
0.4353768825531006,
-0.1493096947669983,
-0.010041633620858192,
-0.21017508208751678,
-0.04815349355340004,
0.40467870235443115,
-0.42574286460876465,
0.44955945014953613,
-0.3895585536956787,
-0.14400623738765717,
-0.06164669618010521,
-0.4255017340183258,
0.468642830... |
9358 | sodium may substitute for pure sodium in fast breeder nuclear reactors. Rubidium and caesium are often used in atomic clocks. Caesium atomic clocks are extraordinarily accurate; if a clock had been made at the time of the dinosaurs, it would be off by less than four seconds (after 80 million years). For that reason, caesium atoms are used as the definition of the second. Rubidium ions are often used in purple fireworks, and caesium is often used in drilling fluids in the petroleum industry. Francium has no commercial applications, but because of francium's relatively simple atomic structure, among other things, | "Alkali metal" | [
0.14049115777015686,
0.4061104655265808,
-0.15725953876972198,
0.03885578736662865,
-0.29780030250549316,
-0.10112816840410233,
0.12545821070671082,
-0.1356787234544754,
0.45470935106277466,
-0.20604656636714935,
0.23435334861278534,
0.07839943468570709,
-0.3234025239944458,
0.627013921737... |
9359 | it has been used in spectroscopy experiments, leading to more information regarding energy levels and the coupling constants between subatomic particles. Studies on the light emitted by laser-trapped francium-210 ions have provided accurate data on transitions between atomic energy levels, similar to those predicted by quantum theory. Pure alkali metals are dangerously reactive with air and water and must be kept away from heat, fire, oxidising agents, acids, most organic compounds, halocarbons, plastics, and moisture. They also react with carbon dioxide and carbon tetrachloride, so that normal fire extinguishers are counterproductive when used on alkali metal fires. Some Class D | "Alkali metal" | [
0.2514978349208832,
0.5792388916015625,
-0.0535428561270237,
-0.18291690945625305,
-0.19621603190898895,
-0.40703076124191284,
0.5862637162208557,
-0.4319753348827362,
0.5975923538208008,
-0.3074493110179901,
-0.20499427616596222,
0.258518785238266,
-0.6755309104919434,
0.4977152943611145,... |
9360 | dry powder extinguishers designed for metal fires are effective, depriving the fire of oxygen and cooling the alkali metal. Experiments are usually conducted using only small quantities of a few grams in a fume hood. Small quantities of lithium may be disposed of by reaction with cool water, but the heavier alkali metals should be dissolved in the less reactive isopropanol. The alkali metals must be stored under mineral oil or an inert atmosphere. The inert atmosphere used may be argon or nitrogen gas, except for lithium, which reacts with nitrogen. Rubidium and caesium must be kept away from air, | "Alkali metal" | [
0.16801667213439941,
0.6832984089851379,
-0.27306297421455383,
0.06142718717455864,
0.13084688782691956,
-0.28726834058761597,
0.37824714183807373,
-0.34230905771255493,
0.5226627588272095,
0.009384780190885067,
-0.2733567953109741,
0.3401155173778534,
-0.5495984554290771,
0.35966429114341... |
9361 | even under oil, because even a small amount of air diffused into the oil may trigger formation of the dangerously explosive peroxide; for the same reason, potassium should not be stored under oil in an oxygen-containing atmosphere for longer than 6 months. The bioinorganic chemistry of the alkali metal ions has been extensively reviewed. Solid state crystal structures have been determined for many complexes of alkali metal ions in small peptides, nucleic acid constituents, carbohydrates and ionophore complexes. Lithium naturally only occurs in traces in biological systems and has no known biological role, but does have effects on the body | "Alkali metal" | [
0.11133299022912979,
0.6837032437324524,
-0.12678056955337524,
-0.1864171028137207,
0.12509135901927948,
0.03944342955946922,
0.26361167430877686,
-0.38473281264305115,
0.4906529486179352,
-0.03988105431199074,
-0.025213634595274925,
0.4021887481212616,
-0.585780680179596,
0.36231213808059... |
9362 | when ingested. Lithium carbonate is used as a mood stabiliser in psychiatry to treat bipolar disorder (manic-depression) in daily doses of about 0.5 to 2 grams, although there are side-effects. Excessive ingestion of lithium causes drowsiness, slurred speech and vomiting, among other symptoms, and poisons the central nervous system, which is dangerous as the required dosage of lithium to treat bipolar disorder is only slightly lower than the toxic dosage. Its biochemistry, the way it is handled by the human body and studies using rats and goats suggest that it is an essential trace element, although the natural biological function | "Alkali metal" | [
-0.04179690405726433,
0.9279606342315674,
-0.3500118553638458,
-0.3188450038433075,
-0.10817184299230576,
-0.13626308739185333,
0.5464980006217957,
-0.22373005747795105,
0.4812440872192383,
-0.02105812355875969,
0.12305938452482224,
0.31594419479370117,
-0.48189371824264526,
0.161477342247... |
9363 | of lithium in humans has yet to be identified. Sodium and potassium occur in all known biological systems, generally functioning as electrolytes inside and outside cells. Sodium is an essential nutrient that regulates blood volume, blood pressure, osmotic equilibrium and pH; the minimum physiological requirement for sodium is 500 milligrams per day. Sodium chloride (also known as common salt) is the principal source of sodium in the diet, and is used as seasoning and preservative, such as for pickling and jerky; most of it comes from processed foods. The Dietary Reference Intake for sodium is 1.5 grams per day, but | "Alkali metal" | [
0.0665082186460495,
0.5883334279060364,
-0.012865222990512848,
-0.1351526975631714,
0.1376885175704956,
0.12943826615810394,
0.1697399914264679,
-0.22486597299575806,
0.4898396134376526,
-0.32484903931617737,
0.11816246062517166,
0.3782346248626709,
-0.3236100375652313,
0.15894554555416107... |
9364 | most people in the United States consume more than 2.3 grams per day, the minimum amount that promotes hypertension; this in turn causes 7.6 million premature deaths worldwide. Potassium is the major cation (positive ion) inside animal cells, while sodium is the major cation outside animal cells. The concentration differences of these charged particles causes a difference in electric potential between the inside and outside of cells, known as the membrane potential. The balance between potassium and sodium is maintained by ion transporter proteins in the cell membrane. The cell membrane potential created by potassium and sodium ions allows the | "Alkali metal" | [
0.06999475508928299,
0.611641526222229,
0.024898909032344818,
-0.08004491776227951,
-0.04848047345876694,
-0.03220279887318611,
0.371802419424057,
-0.42616569995880127,
0.289625346660614,
-0.43892011046409607,
0.23001833260059357,
-0.06870359927415848,
-0.7866659760475159,
0.42475757002830... |
9365 | cell to generate an action potential—a "spike" of electrical discharge. The ability of cells to produce electrical discharge is critical for body functions such as neurotransmission, muscle contraction, and heart function. Disruption of this balance may thus be fatal: for example, ingestion of large amounts of potassium compounds can lead to hyperkalemia strongly influencing the cardiovascular system. Potassium chloride is used in the United States for lethal injection executions. Due to their similar atomic radii, rubidium and caesium in the body mimic potassium and are taken up similarly. Rubidium has no known biological role, but may help stimulate metabolism, and, | "Alkali metal" | [
0.27451691031455994,
0.44831597805023193,
-0.3600432276725769,
0.012196560390293598,
-0.2624012529850006,
-0.23674751818180084,
0.491068571805954,
-0.3870609998703003,
0.4449673593044281,
-0.21270297467708588,
0.1993013322353363,
-0.025201531127095222,
-0.7069731950759888,
0.37808659672737... |
9366 | similarly to caesium, replace potassium in the body causing potassium deficiency. Partial substitution is quite possible and rather non-toxic: a 70 kg person contains on average 0.36 g of rubidium, and an increase in this value by 50 to 100 times did not show negative effects in test persons. Rats can survive up to 50% substitution of potassium by rubidium. Rubidium (and to a much lesser extent caesium) can function as temporary cures for hypokalemia; while rubidium can adequately physiologically substitute potassium in some systems, caesium is never able to do so. There is only very limited evidence in the | "Alkali metal" | [
0.10278400778770447,
0.5638429522514343,
-0.3488229513168335,
0.03191227838397026,
-0.4622460603713989,
-0.1072649210691452,
0.691281795501709,
-0.37727221846580505,
0.4221641719341278,
-0.37764090299606323,
0.14801838994026184,
0.02740149199962616,
-0.5323573350906372,
0.17153415083885193... |
9367 | form of deficiency symptoms for rubidium being possibly essential in goats; even if this is true, the trace amounts usually present in food are more than enough. Caesium compounds are rarely encountered by most people, but most caesium compounds are mildly toxic. Like rubidium, caesium tends to substitute potassium in the body, but is significantly larger and is therefore a poorer substitute. Excess caesium can lead to hypokalemia, arrythmia, and acute cardiac arrest, but such amounts would not ordinarily be encountered in natural sources. As such, caesium is not a major chemical environmental pollutant. The median lethal dose (LD) value | "Alkali metal" | [
0.2173297256231308,
0.7970768213272095,
-0.3706837594509125,
-0.020436812192201614,
-0.4313708245754242,
-0.2971345782279968,
0.7125372290611267,
-0.21180301904678345,
0.5119295120239258,
-0.5080410242080688,
0.039467666298151016,
0.16502641141414642,
-0.45536574721336365,
0.29141622781753... |
9368 | for caesium chloride in mice is 2.3 g per kilogram, which is comparable to the LD values of potassium chloride and sodium chloride. Caesium chloride has been promoted as an alternative cancer therapy, but has been linked to the deaths of over 50 patients, on whom it was used as part of a scientifically unvalidated cancer treatment. Radioisotopes of caesium require special precautions: the improper handling of caesium-137 gamma ray sources can lead to release of this radioisotope and radiation injuries. Perhaps the best-known case is the Goiânia accident of 1987, in which an improperly-disposed-of radiation therapy system from an | "Alkali metal" | [
0.15394756197929382,
0.5172192454338074,
-0.29577693343162537,
-0.02291025221347809,
-0.10526959598064423,
0.009659224189817905,
0.364238440990448,
-0.5433776378631592,
0.19505690038204193,
-0.01087078358978033,
0.35678237676620483,
-0.01532466895878315,
-0.5644451379776001,
0.479838013648... |
9369 | abandoned clinic in the city of Goiânia, Brazil, was scavenged from a junkyard, and the glowing caesium salt sold to curious, uneducated buyers. This led to four deaths and serious injuries from radiation exposure. Together with caesium-134, iodine-131, and strontium-90, caesium-137 was among the isotopes distributed by the Chernobyl disaster which constitute the greatest risk to health. Radioisotopes of francium would presumably be dangerous as well due to their high decay energy and short half-life, but none have been produced in large enough amounts to pose any serious risk. Alkali metal The alkali metals are a group (column) in the | "Alkali metal" | [
0.33544284105300903,
0.6137035489082336,
-0.3158339560031891,
0.07354896515607834,
-0.2230309695005417,
-0.03636186942458153,
0.293698787689209,
-0.23947933316230774,
0.4964563846588135,
-0.011676865629851818,
0.0883178636431694,
0.016911961138248444,
-0.7004725337028503,
0.627755641937255... |
9370 | Alphabet An alphabet is a standard set of letters (basic written symbols or graphemes) that represent the phonemes (basic significant sounds) of any spoken language it is used to write. This is in contrast to other types of writing systems, such as syllabaries (in which each character represents a syllable) and logographic systems (in which each character represents a word, morpheme, or semantic unit). The first fully phonemic script, the Proto-Canaanite script, later known as the Phoenician alphabet, is considered to be the first alphabet, and is the ancestor of most modern alphabets, including Arabic, Greek, Latin, Cyrillic, Hebrew, and | Alphabet | [
0.09240951389074326,
0.2862499952316284,
-0.5633658170700073,
-0.26718440651893616,
0.02913845144212246,
0.628339946269989,
0.47260046005249023,
0.6024333834648132,
0.10186959058046341,
-1.063226580619812,
-0.17007187008857727,
0.03589177504181862,
-0.4412534832954407,
0.2199556976556778,
... |
9371 | possibly Brahmic. Peter T. Daniels, however, distinguishes an abugida or alphasyllabary, a set of graphemes that represent consonantal base letters which diacritics modify to represent vowels (as in Devanagari and other South Asian scripts), an abjad, in which letters predominantly or exclusively represent consonants (as in the original Phoenician, Hebrew or Arabic), and an "alphabet," a set of graphemes that represent both vowels and consonants. In this narrow sense of the word the first "true" alphabet was the Greek alphabet, which was developed on the basis of the earlier Phoenician alphabet. Of the dozens of alphabets in use today, the | Alphabet | [
-0.12250956892967224,
0.09448660910129547,
-0.3537485897541046,
-0.2556580603122711,
-0.16171331703662872,
0.619662344455719,
0.4563470184803009,
0.3685360848903656,
-0.24229469895362854,
-0.8703711032867432,
0.020239658653736115,
0.10843334347009659,
-0.5879428386688232,
0.160889491438865... |
9372 | most popular is the Latin alphabet, which was derived from the Greek, and which many languages modify by adding letters formed using diacritical marks. While most alphabets have letters composed of lines (linear writing), there are also exceptions such as the alphabets used in Braille. The Khmer alphabet (for Cambodian) is the longest, with 74 letters. Alphabets are usually associated with a standard ordering of letters. This makes them useful for purposes of collation, specifically by allowing words to be sorted in alphabetical order. It also means that their letters can be used as an alternative method of "numbering" ordered | Alphabet | [
0.021883195266127586,
0.3366328775882721,
-0.06960643827915192,
-0.18140973150730133,
-0.31868603825569153,
0.42621415853500366,
0.3395766615867615,
0.29158613085746765,
-0.38473689556121826,
-0.563309371471405,
-0.2509736716747284,
-0.2284955531358719,
-0.12504532933235168,
-0.14986865222... |
9373 | items, in such contexts as numbered lists and number placements. The English word "alphabet" came into Middle English from the Late Latin word "alphabetum", which in turn originated in the Greek ἀλφάβητος ("alphabētos"). The Greek word was made from the first two letters, "alpha"(α) and "beta"(β). The names for the Greek letters came from the first two letters of the Phoenician alphabet; "aleph", which also meant "ox", and "bet", which also meant "house". Sometimes, like in the alphabet song in English, the term "ABCs" is used instead of the word "alphabet" ("Now I know my ABCs"...). "Knowing one's ABCs", in | Alphabet | [
0.1849825084209442,
0.17083001136779785,
-0.12092716246843338,
-0.5651309490203857,
-0.1459372490644455,
0.6496716141700745,
0.3018038272857666,
0.027950672432780266,
-0.10117208957672119,
-0.7303925156593323,
-0.14294660091400146,
0.0035804298240691423,
-0.2873370051383972,
0.176841631531... |
9374 | general, can be used as a metaphor for knowing the basics about anything. The history of the alphabet started in ancient Egypt. Egyptian writing had a set of some 24 hieroglyphs that are called uniliterals, to represent syllables that begin with a single consonant of their language, plus a vowel (or no vowel) to be supplied by the native speaker. These glyphs were used as pronunciation guides for logograms, to write grammatical inflections, and, later, to transcribe loan words and foreign names. In the Middle Bronze Age, an apparently "alphabetic" system known as the Proto-Sinaitic script appears in Egyptian turquoise | Alphabet | [
0.17379426956176758,
0.2026456892490387,
-0.40418776869773865,
-0.1636229306459427,
-0.263867050409317,
0.773817777633667,
0.45243149995803833,
0.3260519802570343,
-0.01899176649749279,
-0.8400373458862305,
0.07272030413150787,
-0.13457423448562622,
-0.3792174458503723,
0.2750852704048157,... |
9375 | mines in the Sinai peninsula dated to circa the 15th century BC, apparently left by Canaanite workers. In 1999, John and Deborah Darnell discovered an even earlier version of this first alphabet at Wadi el-Hol dated to circa 1800 BC and showing evidence of having been adapted from specific forms of Egyptian hieroglyphs that could be dated to circa 2000 BC, strongly suggesting that the first alphabet had been developed about that time. Based on letter appearances and names, it is believed to be based on Egyptian hieroglyphs. This script had no characters representing vowels, although originally it probably was | Alphabet | [
0.15013636648654938,
0.26574644446372986,
-0.3331054747104645,
-0.26562952995300293,
0.11455073207616806,
0.5883449912071228,
0.3645801246166229,
0.11062842607498169,
-0.18029800057411194,
-0.9098454713821411,
0.076215460896492,
-0.2942972183227539,
-0.6113235354423523,
0.18939827382564545... |
9376 | a syllabary, but unneeded symbols were discarded. An alphabetic cuneiform script with 30 signs including three that indicate the following vowel was invented in Ugarit before the 15th century BC. This script was not used after the destruction of Ugarit. The Proto-Sinaitic script eventually developed into the Phoenician alphabet, which is conventionally called "Proto-Canaanite" before ca. 1050 BC. The oldest text in Phoenician script is an inscription on the sarcophagus of King Ahiram. This script is the parent script of all western alphabets. By the tenth century, two other forms can be distinguished, namely Canaanite and Aramaic. The Aramaic gave | Alphabet | [
-0.11848168075084686,
0.42436307668685913,
-0.3233373165130615,
-0.2567417025566101,
-0.18859393894672394,
0.8606257438659668,
0.2623661458492279,
0.36853259801864624,
-0.025198763236403465,
-0.9471348524093628,
0.03727985545992851,
0.01911740005016327,
-0.42410171031951904,
0.123571954667... |
9377 | rise to the Hebrew script. The South Arabian alphabet, a sister script to the Phoenician alphabet, is the script from which the Ge'ez alphabet (an abugida) is descended. Vowelless alphabets, which are not true alphabets, are called abjads, currently exemplified in scripts including Arabic, Hebrew, and Syriac. The omission of vowels was not always a satisfactory solution and some "weak" consonants are sometimes used to indicate the vowel quality of a syllable (matres lectionis). These letters have a dual function since they are also used as pure consonants. The Proto-Sinaitic or Proto-Canaanite script and the Ugaritic script were the first | Alphabet | [
-0.21957704424858093,
0.19265156984329224,
-0.38731124997138977,
-0.4269076883792877,
-0.2594984173774719,
0.5596550703048706,
0.4194871783256531,
0.362278550863266,
-0.0866096019744873,
-1.0712491273880005,
-0.021577412262558937,
0.04914075881242752,
-0.43879666924476624,
0.25694549083709... |
9378 | scripts with a limited number of signs, in contrast to the other widely used writing systems at the time, Cuneiform, Egyptian hieroglyphs, and Linear B. The Phoenician script was probably the first phonemic script and it contained only about two dozen distinct letters, making it a script simple enough for common traders to learn. Another advantage of Phoenician was that it could be used to write down many different languages, since it recorded words phonemically. The script was spread by the Phoenicians across the Mediterranean. In Greece, the script was modified to add vowels, giving rise to the ancestor of | Alphabet | [
-0.10689295828342438,
0.07910449802875519,
-0.4102081060409546,
-0.12637673318386078,
-0.050528932362794876,
0.6201585531234741,
0.36525198817253113,
0.4122817814350128,
-0.22276780009269714,
-0.9550321102142334,
0.21722973883152008,
-0.04069707915186882,
-0.2230977714061737,
-0.1036828160... |
9379 | all alphabets in the West. The vowels have independent letter forms separate from those of consonants; therefore it was the first true alphabet. The Greeks chose letters representing sounds that did not exist in Greek to represent vowels. Vowels are significant in the Greek language, and the syllabical Linear B script that was used by the Mycenaean Greeks from the 16th century BC had 87 symbols, including 5 vowels. In its early years, there were many variants of the Greek alphabet, a situation that caused many different alphabets to evolve from it. The Greek alphabet, in its Euboean form, was | Alphabet | [
-0.1450832635164261,
0.32319435477256775,
-0.3484574556350708,
-0.4207335114479065,
-0.11354316771030426,
0.9324942827224731,
0.5388250946998596,
0.3232664465904236,
-0.2726927399635315,
-0.8526193499565125,
0.03506182134151459,
0.04374484717845917,
-0.41498634219169617,
0.0841925516724586... |
9380 | carried over by Greek colonists to the Italian peninsula, where it gave rise to a variety of alphabets used to write the Italic languages. One of these became the Latin alphabet, which was spread across Europe as the Romans expanded their empire. Even after the fall of the Roman state, the alphabet survived in intellectual and religious works. It eventually became used for the descendant languages of Latin (the Romance languages) and then for most of the other languages of Europe. Some adaptations of the Latin alphabet are augmented with ligatures, such as æ in Danish and Icelandic and Ȣ | Alphabet | [
-0.039871156215667725,
0.00555439805611968,
-0.07251782715320587,
-0.4181979298591614,
-0.12827323377132416,
0.5411931872367859,
0.53049236536026,
0.4483441114425659,
-0.22126948833465576,
-0.7394886612892151,
0.011529464274644852,
-0.15222257375717163,
-0.3304777443408966,
-0.155023589730... |
9381 | in Algonquian; by borrowings from other alphabets, such as the thorn þ in Old English and Icelandic, which came from the Futhark runes; and by modifying existing letters, such as the eth ð of Old English and Icelandic, which is a modified "d". Other alphabets only use a subset of the Latin alphabet, such as Hawaiian, and Italian, which uses the letters "j, k, x, y" and "w" only in foreign words. Another notable script is Elder Futhark, which is believed to have evolved out of one of the Old Italic alphabets. Elder Futhark gave rise to a variety of | Alphabet | [
0.1402120590209961,
0.12120987474918365,
0.012844902463257313,
-0.12854264676570892,
-0.2535325586795807,
0.3140888214111328,
0.45159000158309937,
0.22741231322288513,
-0.05705663934350014,
-1.0124236345291138,
-0.02279660664498806,
0.06276393681764603,
0.00404236139729619,
-0.198491379618... |
9382 | alphabets known collectively as the Runic alphabets. The Runic alphabets were used for Germanic languages from AD 100 to the late Middle Ages. Its usage is mostly restricted to engravings on stone and jewelry, although inscriptions have also been found on bone and wood. These alphabets have since been replaced with the Latin alphabet, except for decorative usage for which the runes remained in use until the 20th century. The Old Hungarian script is a contemporary writing system of the Hungarians. It was in use during the entire history of Hungary, albeit not as an official writing system. From the | Alphabet | [
-0.06566587835550308,
0.3284434676170349,
-0.21641799807548523,
-0.3350299596786499,
-0.289539098739624,
0.526922881603241,
0.6248734593391418,
0.4066798985004425,
-0.3000408411026001,
-0.7320685982704163,
-0.11377983540296555,
-0.2887911796569824,
-0.20998728275299072,
-0.1946532577276229... |
9383 | 19th century it once again became more and more popular. The Glagolitic alphabet was the initial script of the liturgical language Old Church Slavonic and became, together with the Greek uncial script, the basis of the Cyrillic script. Cyrillic is one of the most widely used modern alphabetic scripts, and is notable for its use in Slavic languages and also for other languages within the former Soviet Union. Cyrillic alphabets include the Serbian, Macedonian, Bulgarian, Russian, Belarusian and Ukrainian. The Glagolitic alphabet is believed to have been created by Saints Cyril and Methodius, while the Cyrillic alphabet was invented by | Alphabet | [
-0.05818553641438484,
0.17889097332954407,
0.10165365785360336,
-0.39324748516082764,
-0.11293519288301468,
0.6164376735687256,
0.47568947076797485,
0.5215179920196533,
-0.28773069381713867,
-0.6377106308937073,
-0.17380647361278534,
-0.1461179405450821,
-0.7337202429771423,
0.105750143527... |
9384 | Clement of Ohrid, who was their disciple. They feature many letters that appear to have been borrowed from or influenced by the Greek alphabet and the Hebrew alphabet. The longest European alphabet is the Latin-derived Slovak alphabet which has 46 letters. Beyond the logographic Chinese writing, many phonetic scripts are in existence in Asia. The Arabic alphabet, Hebrew alphabet, Syriac alphabet, and other abjads of the Middle East are developments of the Aramaic alphabet, but because these writing systems are largely consonant-based they are often not considered true alphabets. Most alphabetic scripts of India and Eastern Asia are descended from | Alphabet | [
0.10058324784040451,
0.1989377737045288,
-0.17498286068439484,
-0.37853920459747314,
0.052848540246486664,
0.6410801410675049,
0.507055938243866,
0.3387559950351715,
-0.26554080843925476,
-1.016517162322998,
-0.07660755515098572,
-0.25616204738616943,
-0.379580557346344,
0.1847612708806991... |
9385 | the Brahmi script, which is often believed to be a descendant of Aramaic. In Korea, the Hangul alphabet was created by Sejong the Great. Hangul is a unique alphabet: it is a featural alphabet, where many of the letters are designed from a sound's place of articulation (P to look like the widened mouth, L to look like the tongue pulled in, etc.); its design was planned by the government of the day; and it places individual letters in syllable clusters with equal dimensions, in the same way as Chinese characters, to allow for mixed-script writing (one syllable always takes | Alphabet | [
-0.24124182760715485,
0.12047429382801056,
-0.12992556393146515,
-0.39539700746536255,
-0.4524073004722595,
0.6791238188743591,
0.5101729035377502,
0.24573075771331787,
-0.3757181465625763,
-0.6925745010375977,
-0.1771552860736847,
-0.3803313672542572,
-0.3193676769733429,
-0.0740898400545... |
9386 | up one type-space no matter how many letters get stacked into building that one sound-block). Zhuyin (sometimes called "Bopomofo") is a semi-syllabary used to phonetically transcribe Mandarin Chinese in the Republic of China. After the later establishment of the People's Republic of China and its adoption of Hanyu Pinyin, the use of Zhuyin today is limited, but it is still widely used in Taiwan where the Republic of China still governs. Zhuyin developed out of a form of Chinese shorthand based on Chinese characters in the early 1900s and has elements of both an alphabet and a syllabary. Like an | Alphabet | [
0.2641306221485138,
0.11538316309452057,
0.1567755490541458,
-0.22610615193843842,
-0.17034479975700378,
0.19615665078163147,
-0.3490186035633087,
0.22326359152793884,
-0.10975178331136703,
-0.565236508846283,
-0.04896373301744461,
-0.0471915602684021,
-0.365529865026474,
-0.05873574316501... |
9387 | alphabet the phonemes of syllable initials are represented by individual symbols, but like a syllabary the phonemes of the syllable finals are not; rather, each possible final (excluding the medial glide) is represented by its own symbol. For example, "luan" is represented as ㄌㄨㄢ ("l-u-an"), where the last symbol ㄢ represents the entire final "-an". While Zhuyin is not used as a mainstream writing system, it is still often used in ways similar to a romanization system—that is, for aiding in pronunciation and as an input method for Chinese characters on computers and cellphones. European alphabets, especially Latin and Cyrillic, | Alphabet | [
0.020936643704771996,
0.3409571647644043,
0.06609142571687698,
-0.39286187291145325,
-0.15110833942890167,
0.5332524180412292,
0.2755560278892517,
0.37871798872947693,
-0.21495500206947327,
-0.8168037533760071,
-0.10345284640789032,
-0.24599555134773254,
-0.1754150539636612,
-0.05704581737... |
9388 | have been adapted for many languages of Asia. Arabic is also widely used, sometimes as an abjad (as with Urdu and Persian) and sometimes as a complete alphabet (as with Kurdish and Uyghur). The term "alphabet" is used by linguists and paleographers in both a wide and a narrow sense. In the wider sense, an alphabet is a script that is "segmental" at the phoneme level—that is, it has separate glyphs for individual sounds and not for larger units such as syllables or words. In the narrower sense, some scholars distinguish "true" alphabets from two other types of segmental script, | Alphabet | [
0.04396790638566017,
0.21697477996349335,
-0.12536384165287018,
-0.2589541971683502,
-0.1687963902950287,
0.5686735510826111,
0.5045337080955505,
0.39214152097702026,
-0.29325729608535767,
-0.7685213088989258,
-0.33496829867362976,
-0.2309909164905548,
-0.3493901193141937,
0.22052922844886... |
9389 | abjads and abugidas. These three differ from each other in the way they treat vowels: abjads have letters for consonants and leave most vowels unexpressed; abugidas are also consonant-based, but indicate vowels with diacritics to or a systematic graphic modification of the consonants. In alphabets in the narrow sense, on the other hand, consonants and vowels are written as independent letters. The earliest known alphabet in the wider sense is the Wadi el-Hol script, believed to be an abjad, which through its successor Phoenician is the ancestor of modern alphabets, including Arabic, Greek, Latin (via the Old Italic alphabet), Cyrillic | Alphabet | [
-0.14589180052280426,
0.38784801959991455,
-0.636527419090271,
-0.49093613028526306,
-0.21823851764202118,
0.644286036491394,
0.30620646476745605,
0.3305579423904419,
-0.12350720912218094,
-1.0440700054168701,
-0.038252510130405426,
0.06555455178022385,
-0.5871899724006653,
0.1781290024518... |
9390 | (via the Greek alphabet) and Hebrew (via Aramaic). Examples of present-day abjads are the Arabic and Hebrew scripts; true alphabets include Latin, Cyrillic, and Korean hangul; and abugidas are used to write Tigrinya, Amharic, Hindi, and Thai. The Canadian Aboriginal syllabics are also an abugida rather than a syllabary as their name would imply, since each glyph stands for a consonant that is modified by rotation to represent the following vowel. (In a true syllabary, each consonant-vowel combination would be represented by a separate glyph.) All three types may be augmented with syllabic glyphs. Ugaritic, for example, is basically an | Alphabet | [
-0.12659265100955963,
0.5174606442451477,
-0.33872556686401367,
-0.28100597858428955,
-0.20868892967700958,
0.7314022779464722,
0.6305003762245178,
0.6449668407440186,
0.0040750144980847836,
-0.7946531176567078,
-0.09133905917406082,
0.16484688222408295,
-0.4970276653766632,
0.070349268615... |
9391 | abjad, but has syllabic letters for . (These are the only time vowels are indicated.) Cyrillic is basically a true alphabet, but has syllabic letters for (я, е, ю); Coptic has a letter for . Devanagari is typically an abugida augmented with dedicated letters for initial vowels, though some traditions use अ as a zero consonant as the graphic base for such vowels. The boundaries between the three types of segmental scripts are not always clear-cut. For example, Sorani Kurdish is written in the Arabic script, which is normally an abjad. However, in Kurdish, writing the vowels is mandatory, and | Alphabet | [
-0.1023789569735527,
0.2281002253293991,
-0.24064196646213531,
-0.44813618063926697,
-0.34144479036331177,
0.6101674437522888,
0.655573308467865,
0.2089758962392807,
-0.276847779750824,
-0.49763208627700806,
-0.1366017758846283,
0.04892820864915848,
-0.6326571702957153,
0.05646366998553276... |
9392 | full letters are used, so the script is a true alphabet. Other languages may use a Semitic abjad with mandatory vowel diacritics, effectively making them abugidas. On the other hand, the Phagspa script of the Mongol Empire was based closely on the Tibetan abugida, but all vowel marks were written after the preceding consonant rather than as diacritic marks. Although short "a" was not written, as in the Indic abugidas, one could argue that the linear arrangement made this a true alphabet. Conversely, the vowel marks of the Tigrinya abugida and the Amharic abugida (ironically, the original source of the | Alphabet | [
-0.18910019099712372,
0.24124538898468018,
-0.27578580379486084,
-0.39261969923973083,
-0.6207777857780457,
0.4251498878002167,
0.5594843626022339,
0.10109281539916992,
-0.2918757498264313,
-0.6779372096061707,
-0.031242642551660538,
-0.092103973031044,
-0.6179592609405518,
-0.120961904525... |
9393 | term "abugida") have been so completely assimilated into their consonants that the modifications are no longer systematic and have to be learned as a syllabary rather than as a segmental script. Even more extreme, the Pahlavi abjad eventually became logographic. (See below.) Thus the primary classification of alphabets reflects how they treat vowels. For tonal languages, further classification can be based on their treatment of tone, though names do not yet exist to distinguish the various types. Some alphabets disregard tone entirely, especially when it does not carry a heavy functional load, as in Somali and many other languages of | Alphabet | [
-0.14933912456035614,
0.2683805525302887,
-0.2225106805562973,
-0.4912986159324646,
-0.2598680555820465,
0.34416791796684265,
0.5452191829681396,
0.2668144702911377,
-0.3644040822982788,
-0.9107840061187744,
-0.20951609313488007,
-0.007228023372590542,
-0.5057653188705444,
0.26737913489341... |
9394 | Africa and the Americas. Such scripts are to tone what abjads are to vowels. Most commonly, tones are indicated with diacritics, the way vowels are treated in abugidas. This is the case for Vietnamese (a true alphabet) and Thai (an abugida). In Thai, tone is determined primarily by the choice of consonant, with diacritics for disambiguation. In the Pollard script, an abugida, vowels are indicated by diacritics, but the placement of the diacritic relative to the consonant is modified to indicate the tone. More rarely, a script may have separate letters for tones, as is the case for Hmong and | Alphabet | [
-0.2325000762939453,
0.08579210937023163,
-0.2765173316001892,
-0.27327674627304077,
0.08045755326747894,
0.6894000172615051,
0.42677566409111023,
0.517510175704956,
-0.12304740399122238,
-0.7840838432312012,
-0.15260234475135803,
0.0718977078795433,
-0.19411471486091614,
-0.18277429044246... |
9395 | Zhuang. For most of these scripts, regardless of whether letters or diacritics are used, the most common tone is not marked, just as the most common vowel is not marked in Indic abugidas; in Zhuyin not only is one of the tones unmarked, but there is a diacritic to indicate lack of tone, like the virama of Indic. The number of letters in an alphabet can be quite small. The Book Pahlavi script, an abjad, had only twelve letters at one point, and may have had even fewer later on. Today the Rotokas alphabet has only twelve letters. (The Hawaiian | Alphabet | [
-0.1777876615524292,
0.10354176163673401,
-0.18177440762519836,
-0.40304893255233765,
-0.1593988686800003,
0.5256036520004272,
0.16169755160808563,
0.09407182037830353,
-0.16816064715385437,
-0.6956289410591125,
0.10564424842596054,
-0.07453400641679764,
-0.2799362540245056,
-0.29022669792... |
9396 | alphabet is sometimes claimed to be as small, but it actually consists of 18 letters, including the ʻokina and five long vowels. However, Hawaiian Braille has only 13 letters.) While Rotokas has a small alphabet because it has few phonemes to represent (just eleven), Book Pahlavi was small because many letters had been "conflated"—that is, the graphic distinctions had been lost over time, and diacritics were not developed to compensate for this as they were in Arabic, another script that lost many of its distinct letter shapes. For example, a comma-shaped letter represented "g", "d", "y", "k", or "j". However, | Alphabet | [
0.1667565256357193,
0.10333731025457382,
-0.06633442640304565,
-0.23238834738731384,
-0.11355862021446228,
0.5922850966453552,
0.4834810495376587,
-0.06390602886676788,
-0.21559648215770721,
-0.626859724521637,
0.08667456358671188,
0.060369301587343216,
-0.21488085389137268,
-0.02319090440... |
9397 | such apparent simplifications can perversely make a script more complicated. In later Pahlavi papyri, up to half of the remaining graphic distinctions of these twelve letters were lost, and the script could no longer be read as a sequence of letters at all, but instead each word had to be learned as a whole—that is, they had become logograms as in Egyptian Demotic. The largest segmental script is probably an abugida, Devanagari. When written in Devanagari, Vedic Sanskrit has an alphabet of 53 letters, including the "visarga" mark for final aspiration and special letters for "kš" and "jñ," though one | Alphabet | [
-0.11396335065364838,
0.027701284736394882,
-0.2134801745414734,
-0.3004862368106842,
-0.4417344033718109,
0.8306821584701538,
0.5386990904808044,
0.10236995667219162,
-0.3336450755596161,
-0.6232103705406189,
0.013117517344653606,
-0.3789185881614685,
-0.2118876427412033,
0.42993298172950... |
9398 | of the letters is theoretical and not actually used. The Hindi alphabet must represent both Sanskrit and modern vocabulary, and so has been expanded to 58 with the "khutma" letters (letters with a dot added) to represent sounds from Persian and English. Thai has a total of 59 symbols, consisting of 44 consonants, 13 vowels and 2 syllabics, not including 4 diacritics for tone marks and one for vowel length. The largest known abjad is Sindhi, with 51 letters. The largest alphabets in the narrow sense include Kabardian and Abkhaz (for Cyrillic), with 58 and 56 letters, respectively, and Slovak | Alphabet | [
0.06204250454902649,
0.2997801899909973,
-0.10249271988868713,
-0.32862764596939087,
-0.165665864944458,
1.0353213548660278,
0.7454113364219666,
0.3200306296348572,
-0.19969554245471954,
-0.6177322864532471,
-0.0574246384203434,
-0.009507769718766212,
-0.3341200053691864,
0.233235910534858... |
9399 | (for the Latin script), with 46. However, these scripts either count di- and tri-graphs as separate letters, as Spanish did with "ch" and "ll" until recently, or uses diacritics like Slovak "č". The Georgian alphabet ( "") is alphabetical writing system. It is the largest true alphabet where each letter is graphically independent with 33 letters. Original Georgian alphabet had 38 letters but 5 letters were removed in 19th century by Ilia Chavchavadze. The Georgian alphabet is much closer to Greek than the other Caucasian alphabets. The numeric value runs parallel to the Greek one, the consonants without a Greek | Alphabet | [
0.11576653271913528,
0.08631308376789093,
-0.22845590114593506,
-0.3553091287612915,
-0.019411521032452583,
0.6893210411071777,
0.5648310780525208,
0.009407981298863888,
-0.30275827646255493,
-0.6221778988838196,
-0.09168671071529388,
-0.006032250355929136,
-0.656124472618103,
0.1413747519... |
9400 | equivalent are organized at the end of the alphabet. Origins of the alphabet are still unknown, some Armenian and Western scholars believe it was created by Mesrop Mashtots (Armenian: Մեսրոպ Մաշտոց Mesrop Maštoc') also known as Mesrob the Vartabed, who was an early medieval Armenian linguist, theologian, statesman and hymnologist, best known for inventing the Armenian alphabet c. 405 AD, other Georgian and Western, scholars are against this theory. Syllabaries typically contain 50 to 400 glyphs, and the glyphs of logographic systems typically number from the many hundreds into the thousands. Thus a simple count of the number of distinct | Alphabet | [
-0.09028029441833496,
0.4035941958427429,
-0.5258268713951111,
-0.23362308740615845,
-0.22374963760375977,
0.9744793772697449,
0.5814353823661804,
0.2596524655818939,
-0.3314538896083832,
-0.7401593327522278,
-0.011860687285661697,
-0.28154629468917847,
-0.7227416038513184,
0.0756880193948... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.