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Borates have low toxicity in mammals (similar to table salt) but are more toxic to arthropods and are occasionally used as insecticides. Boron-containing organic antibiotics are known. Although only traces are required, it is an essential plant nutrient.
History
The word boron was coined from borax, the mineral from ... | Boron | Wikipedia | 466 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Boron has two naturally occurring and stable isotopes, 11B (80.1%) and 10B (19.9%). The mass difference results in a wide range of δ11B values, which are defined as a fractional difference between the 11B and 10B and traditionally expressed in parts per thousand, in natural waters ranging from −16 to +59. There are 13 ... | Boron | Wikipedia | 369 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Boron forms four major allotropes: α-rhombohedral and β-rhombohedral (α-R and β-R), γ-orthorhombic (γ) and β-tetragonal (β-T). All four phases are stable at ambient conditions, and β-rhombohedral is the most common and stable. An α-tetragonal phase also exists (α-T), but is very difficult to produce without significant... | Boron | Wikipedia | 466 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Reactions of the element
Crystalline boron is a hard, black material with a melting point of above 2000 °C. Crystalline boron is chemically inert and resistant to attack by boiling hydrofluoric or hydrochloric acid. When finely divided, it is attacked slowly by hot concentrated hydrogen peroxide, hot concentrated nitri... | Boron | Wikipedia | 451 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
The trihalides adopt a planar trigonal structures, in contrast to the behavior of aluminium trihalides. All charge-neutral boron halides violate the octet rule, hence they typically are Lewis acidic. For example, boron trifluoride (BF3) combines eagerly with fluoride sources to give the tetrafluoroborate anion, BF4−. B... | Boron | Wikipedia | 501 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Related to the oxides are the alkoxides and boronic acids with the formula B(OR)3 and R2BOH, respectively. Boron forms a wide variety of such metal-organic compounds, some of which are used in the synthesis of pharmaceuticals. These developments, especially the Suzuki reaction, was recognized with the 2010 Nobel Prize... | Boron | Wikipedia | 490 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
This regiochemistry, i.e. the tendency of B to attach to the terminal carbon - is explained by the polarization of the bonds in boranes, which is indicated as Bδ+-Hδ-.
Hydroboration opened the doors for many subsequent reactions, several of which are useful in the synthesis of complex organic compounds. The signific... | Boron | Wikipedia | 493 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Boron carbide is a ceramic material. It is obtained by carbothermal reduction of B2O3in an electric furnace:
2 B2O3 + 7 C → B4C + 6 CO
Boron carbide's structure is only approximately reflected in its formula of B4C, and it shows a clear depletion of carbon from this suggested stoichiometric ratio. This is due to its v... | Boron | Wikipedia | 445 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Economically important sources of boron are the minerals colemanite, rasorite (kernite), ulexite and tincal. Together these constitute 90% of mined boron-containing ore. The largest global borax deposits known, many still untapped, are in Central and Western Turkey, including the provinces of Eskişehir, Kütahya and Bal... | Boron | Wikipedia | 391 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Increasing demand for boric acid has led a number of producers to invest in additional capacity. Turkey's state-owned Eti Mine Works opened a new boric acid plant with the production capacity of 100,000 tonnes per year at Emet in 2003. Rio Tinto Group increased the capacity of its boron plant from 260,000 tonnes per ye... | Boron | Wikipedia | 508 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Fiberglasses, a fiber reinforced polymer sometimes contain borosilicate, borax, or boron oxide, and is added to increase the strength of the glass. The highly boronated glasses, E-glass (named for "Electrical" use) are alumino-borosilicate glass. Another common high-boron glasses, C-glass, also has a high boron oxide ... | Boron | Wikipedia | 510 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
High-hardness and abrasive compounds
Boron carbide and cubic boron nitride powders are widely used as abrasives. Boron nitride is a material isoelectronic to carbon. Similar to carbon, it has both hexagonal (soft graphite-like h-BN) and cubic (hard, diamond-like c-BN) forms. h-BN is used as a high temperature componen... | Boron | Wikipedia | 466 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Sodium perborate serves as a source of active oxygen in many detergents, laundry detergents, cleaning products, and laundry bleaches. However, despite its name, "Borateem" laundry bleach no longer contains any boron compounds, using sodium percarbonate instead as a bleaching agent.
Insecticides and antifungals
Zinc bo... | Boron | Wikipedia | 505 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
In pressurized water reactors a variable concentration of boronic acid in the cooling water is used as a neutron poison to compensate the variable reactivity of the fuel. When new rods are inserted the concentration of boronic acid is maximal, and is reduced during the lifetime.
Other nonmedical uses
Because of its ... | Boron | Wikipedia | 468 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Boric acid has antiseptic, antifungal, and antiviral properties and, for these reasons, is applied as a water clarifier in swimming pool water treatment. Mild solutions of boric acid have been used as eye antiseptics.
Bortezomib (marketed as Velcade and Cytomib). Boron appears as an active element in the organic pharm... | Boron | Wikipedia | 436 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
MgB2
Magnesium diboride (MgB2) is a superconductor with the transition temperature of 39 K. MgB2 wires are produced with the powder-in-tube process and applied in superconducting magnets. A project at CERN to make MgB2 cables has resulted in superconducting test cables able to carry 20,000 amperes for extremely high cu... | Boron | Wikipedia | 458 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
The 10B isotope is useful for capturing thermal neutrons (see neutron cross section#Typical cross sections). The nuclear industry enriches natural boron to nearly pure 10B. The less-valuable by-product, depleted boron, is nearly pure 11B.
Enriched boron or 10B is used in both radiation shielding and is the primary nuc... | Boron | Wikipedia | 381 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Neutron capture therapy
In neutron capture therapy (BNCT) for malignant brain tumors, boron is researched to be used for selectively targeting and destroying tumor cells. The goal is to deliver higher concentrations of the non-radioactive boron isotope (10B) to the tumor cells than to the surrounding normal tissues. Wh... | Boron | Wikipedia | 490 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Boron is an essential plant nutrient, required primarily for maintaining the integrity of cell walls. However, high soil concentrations of greater than 1.0 ppm lead to marginal and tip necrosis in leaves as well as poor overall growth performance. Levels as low as 0.8 ppm produce these same symptoms in plants that are ... | Boron | Wikipedia | 483 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Still, studies suggest that boron may exert beneficial effects on reproduction and development, calcium metabolism, bone formation, brain function, insulin and energy substrate metabolism, immunity, and steroid hormone (including estrogen) and vitamin D function, among other functions. A small human trial published in ... | Boron | Wikipedia | 393 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Elemental boron, boron oxide, boric acid, borates, and many organoboron compounds are relatively nontoxic to humans and animals (with toxicity similar to that of table salt). The LD50 (dose at which there is 50% mortality) for animals is about 6 g per kg of body weight. Substances with an LD50 above 2 g/kg are consider... | Boron | Wikipedia | 383 | 3755 | https://en.wikipedia.org/wiki/Boron | Physical sciences | Chemical elements_2 | null |
Bromine is a chemical element; it has symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825... | Bromine | Wikipedia | 390 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Large amounts of bromide salts are toxic from the action of soluble bromide ions, causing bromism. However, bromine is beneficial for human eosinophils, and is an essential trace element for collagen development in all animals. Hundreds of known organobromine compounds are generated by terrestrial and marine plants and... | Bromine | Wikipedia | 382 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
After the French chemists Louis Nicolas Vauquelin, Louis Jacques Thénard, and Joseph-Louis Gay-Lussac approved the experiments of the young pharmacist Balard, the results were presented at a lecture of the Académie des Sciences and published in Annales de Chimie et Physique. In his publication, Balard stated that he ch... | Bromine | Wikipedia | 348 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Properties
Bromine is the third halogen, being a nonmetal in group 17 of the periodic table. Its properties are thus similar to those of fluorine, chlorine, and iodine, and tend to be intermediate between those of chlorine and iodine, the two neighbouring halogens. Bromine has the electron configuration [Ar]4s3d4p, wit... | Bromine | Wikipedia | 385 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
All four stable halogens experience intermolecular van der Waals forces of attraction, and their strength increases together with the number of electrons among all homonuclear diatomic halogen molecules. Thus, the melting and boiling points of bromine are intermediate between those of chlorine and iodine. As a result o... | Bromine | Wikipedia | 493 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Bromine has two stable isotopes, Br and Br. These are its only two natural isotopes, with Br making up 51% of natural bromine and Br making up the remaining 49%. Both have nuclear spin 3/2− and thus may be used for nuclear magnetic resonance, although Br is more favourable. The relatively 1:1 distribution of the two is... | Bromine | Wikipedia | 445 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Hydrogen bromide
The simplest compound of bromine is hydrogen bromide, HBr. It is mainly used in the production of inorganic bromides and alkyl bromides, and as a catalyst for many reactions in organic chemistry. Industrially, it is mainly produced by the reaction of hydrogen gas with bromine gas at 200–400 °C with a p... | Bromine | Wikipedia | 344 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Unlike hydrogen fluoride, anhydrous liquid hydrogen bromide is difficult to work with as a solvent, because its boiling point is low, it has a small liquid range, its dielectric constant is low and it does not dissociate appreciably into HBr and ions – the latter, in any case, are much less stable than the bifluoride ... | Bromine | Wikipedia | 354 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Bromination of metals with Br tends to yield lower oxidation states than chlorination with Cl when a variety of oxidation states is available. Bromides can be made by reaction of an element or its oxide, hydroxide, or carbonate with hydrobromic acid, and then dehydrated by mildly high temperatures combined with either ... | Bromine | Wikipedia | 407 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Bromine halides
The halogens form many binary, diamagnetic interhalogen compounds with stoichiometries XY, XY, XY, and XY (where X is heavier than Y), and bromine is no exception. Bromine forms a monofluoride and monochloride, as well as a trifluoride and pentafluoride. Some cationic and anionic derivatives are also ch... | Bromine | Wikipedia | 410 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
At room temperature, bromine trifluoride (BrF) is a straw-coloured liquid. It may be formed by directly fluorinating bromine at room temperature and is purified through distillation. It reacts violently with water and explodes on contact with flammable materials, but is a less powerful fluorinating reagent than chlorin... | Bromine | Wikipedia | 400 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Bromine oxides are not as well-characterised as chlorine oxides or iodine oxides, as they are all fairly unstable: it was once thought that they could not exist at all. Dibromine monoxide is a dark-brown solid which, while reasonably stable at −60 °C, decomposes at its melting point of −17.5 °C; it is useful in bromina... | Bromine | Wikipedia | 486 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Bromous acids and bromites are very unstable, although the strontium and barium bromites are known. More important are the bromates, which are prepared on a small scale by oxidation of bromide by aqueous hypochlorite, and are strong oxidising agents. Unlike chlorates, which very slowly disproportionate to chloride and ... | Bromine | Wikipedia | 504 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Organobromides are typically produced by additive or substitutive bromination of other organic precursors. Bromine itself can be used, but due to its toxicity and volatility, safer brominating reagents are normally used, such as N-bromosuccinimide. The principal reactions for organobromides include dehydrobromination, ... | Bromine | Wikipedia | 427 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
The main sources of bromine production are Israel and Jordan. The element is liberated by halogen exchange, using chlorine gas to oxidise Br to Br. This is then removed with a blast of steam or air, and is then condensed and purified. Today, bromine is transported in large-capacity metal drums or lead-lined tanks that ... | Bromine | Wikipedia | 488 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
A number of gaseous or highly volatile brominated halomethane compounds are non-toxic and make superior fire suppressant agents by this same mechanism, and are particularly effective in enclosed spaces such as submarines, airplanes, and spacecraft. However, they are expensive and their production and use has been great... | Bromine | Wikipedia | 490 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
In pharmacology, inorganic bromide compounds, especially potassium bromide, were frequently used as general sedatives in the 19th and early 20th century. Bromides in the form of simple salts are still used as anticonvulsants in both veterinary and human medicine, although the latter use varies from country to country. ... | Bromine | Wikipedia | 511 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
A 2014 study suggests that bromine (in the form of bromide ion) is a necessary cofactor in the biosynthesis of collagen IV, making the element essential to basement membrane architecture and tissue development in animals. Nevertheless, no clear deprivation symptoms or syndromes have been documented in mammals. In other... | Bromine | Wikipedia | 484 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
The bromide anion is not very toxic: a normal daily intake is 2 to 8 milligrams. However, high levels of bromide chronically impair the membrane of neurons, which progressively impairs neuronal transmission, leading to toxicity, known as bromism. Bromide has an elimination half-life of 9 to 12 days, which can lead to e... | Bromine | Wikipedia | 480 | 3756 | https://en.wikipedia.org/wiki/Bromine | Physical sciences | Chemical elements_2 | null |
Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.
The most common minerals of barium are barite (barium sulfate, BaSO4) and with... | Barium | Wikipedia | 393 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
At room temperature and pressure, barium metal adopts a body-centered cubic structure, with a barium–barium distance of 503 picometers, expanding with heating at a rate of approximately 1.8/°C. It is a soft metal with a Mohs hardness of 1.25. Its melting temperature of is intermediate between those of the lighter stro... | Barium | Wikipedia | 454 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
Barium hydroxide ("baryta") was known to alchemists, who produced it by heating barium carbonate. Unlike calcium hydroxide, it absorbs very little CO2 in aqueous solutions and is therefore insensitive to atmospheric fluctuations. This property is used in calibrating pH equipment.
Barium compounds burn with a green to ... | Barium | Wikipedia | 501 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
Carl Scheele determined that baryte contained a new element in 1772, but could not isolate barium, only barium oxide. Johan Gottlieb Gahn also isolated barium oxide two years later in similar studies. Oxidized barium was at first called "barote" by Guyton de Morveau, a name that was changed by Antoine Lavoisier to bary... | Barium | Wikipedia | 420 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
The baryte reserves are estimated between 0.7 and 2 billion tonnes. The highest production, 8.3 million tonnes, was achieved in 1981, but only 7–8% was used for barium metal or compounds. Baryte production has risen since the second half of the 1990s from 5.6 million tonnes in 1996 to 7.6 in 2005 and 7.8 in 2011. China... | Barium | Wikipedia | 500 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
A similar reaction with silicon at yields barium and barium metasilicate. Electrolysis is not used because barium readily dissolves in molten halides and the product is rather impure.
Gemstone
The barium mineral, benitoite (barium titanium silicate), occurs as a very rare blue fluorescent gemstone, and is the officia... | Barium | Wikipedia | 416 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
Barium sulfate (the mineral baryte, BaSO4) is important to the petroleum industry as a drilling fluid in oil and gas wells. The precipitate of the compound (called "blanc fixe", from the French for "permanent white") is used in paints and varnishes; as a filler in ringing ink, plastics, and rubbers; as a paper coating ... | Barium | Wikipedia | 511 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
Palaeoceanography
The lateral mixing of barium is caused by water mass mixing and ocean circulation. Global ocean circulation reveals a strong correlation between dissolved barium and silicic acid. The large-scale ocean circulation combined with remineralization of barium show a similar correlation between dissolved b... | Barium | Wikipedia | 444 | 3757 | https://en.wikipedia.org/wiki/Barium | Physical sciences | Chemical elements_2 | null |
Berkelium is a synthetic chemical element; it has symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory) where i... | Berkelium | Wikipedia | 458 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Berkelium is a soft, silvery-white, radioactive actinide metal. In the periodic table, it is located to the right of the actinide curium, to the left of the actinide californium and below the lanthanide terbium with which it shares many similarities in physical and chemical properties. Its density of 14.78 g/cm3 lies b... | Berkelium | Wikipedia | 459 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Allotropes
At ambient conditions, berkelium assumes its most stable α form which has a hexagonal symmetry, space group P63/mmc, lattice parameters of 341 pm and 1107 pm. The crystal has a double-hexagonal close packing structure with the layer sequence ABAC and so is isotypic (having a similar structure) with α-lanthan... | Berkelium | Wikipedia | 325 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Chemical
Like all actinides, berkelium dissolves in various aqueous inorganic acids, liberating gaseous hydrogen and converting into the state. This trivalent oxidation state (+3) is the most stable, especially in aqueous solutions, but tetravalent (+4), pentavalent (+5), and possibly divalent (+2) berkelium compounds... | Berkelium | Wikipedia | 469 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
On Earth, berkelium is mostly concentrated in certain areas, which were used for the atmospheric nuclear weapons tests between 1945 and 1980, as well as at the sites of nuclear incidents, such as the Chernobyl disaster, Three Mile Island accident and 1968 Thule Air Base B-52 crash. Analysis of the debris at the testing... | Berkelium | Wikipedia | 387 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
The name choice for element 97 followed the previous tradition of the Californian group to draw an analogy between the newly discovered actinide and the lanthanide element positioned above it in the periodic table. Previously, americium was named after a continent as its analogue europium, and curium honored scientists... | Berkelium | Wikipedia | 359 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
After the irradiation, the coating was dissolved with nitric acid and then precipitated as the hydroxide using concentrated aqueous ammonia solution. The product was centrifugated and re-dissolved in nitric acid. To separate berkelium from the unreacted americium, this solution was added to a mixture of ammonium and am... | Berkelium | Wikipedia | 491 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Plutonium-239 is further irradiated by a source that has a high neutron flux, several times higher than a conventional nuclear reactor, such as the 85-megawatt High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory in Tennessee, US. The higher flux promotes fusion reactions involving not one but several ... | Berkelium | Wikipedia | 442 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
The isotope 248Bk was first obtained in 1956 by bombarding a mixture of curium isotopes with 25 MeV α-particles. Although its direct detection was hindered by strong signal interference with 245Bk, the existence of a new isotope was proven by the growth of the decay product 248Cf which had been previously characterized... | Berkelium | Wikipedia | 512 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
A more detailed procedure adopted at the Oak Ridge National Laboratory was as follows: the initial mixture of actinides is processed with ion exchange using lithium chloride reagent, then precipitated as hydroxides, filtered and dissolved in nitric acid. It is then treated with high-pressure elution from cation exchang... | Berkelium | Wikipedia | 480 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
The first berkelium metal sample weighing 1.7 micrograms was prepared in 1971 by the reduction of fluoride with lithium vapor at 1000 °C; the fluoride was suspended on a tungsten wire above a tantalum crucible containing molten lithium. Later, metal samples weighing up to 0.5 milligrams were obtained with this method.... | Berkelium | Wikipedia | 452 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Visible amounts of chloride () were first isolated and characterized in 1962, and weighed only 3 billionths of a gram. It can be prepared by introducing hydrogen chloride vapors into an evacuated quartz tube containing berkelium oxide at a temperature about 500 °C. This green solid has a melting point of 600 °C, and i... | Berkelium | Wikipedia | 511 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
and hydroxides are both stable in 1 molar solutions of sodium hydroxide. phosphate () has been prepared as a solid, which shows strong fluorescence under excitation with a green light. Berkelium hydrides are produced by reacting metal with hydrogen gas at temperatures about 250 °C. They are non-stoichiometric with th... | Berkelium | Wikipedia | 458 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
A 22 milligram batch of berkelium-249 was prepared in a 250-day irradiation and then purified for 90 days at Oak Ridge in 2009. This target yielded the first 6 atoms of tennessine at the Joint Institute for Nuclear Research (JINR), Dubna, Russia, after bombarding it with calcium ions in the U400 cyclotron for 150 days.... | Berkelium | Wikipedia | 366 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Health issues
Little is known about the effects of berkelium on human body, and analogies with other elements may not be drawn because of different radiation products (electrons for berkelium and alpha particles, neutrons, or both for most other actinides). The low energy of electrons emitted from berkelium-249 (less t... | Berkelium | Wikipedia | 307 | 3758 | https://en.wikipedia.org/wiki/Berkelium | Physical sciences | Chemical elements_2 | null |
Bauxite () is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite (FeO(OH)) and haematite (), the alumini... | Bauxite | Wikipedia | 461 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
Australia is the largest producer of bauxite, followed by Guinea and China. Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no overburden. Increased aluminium recycling, which requires less electric power than producing aluminium from ores, may considerab... | Bauxite | Wikipedia | 460 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
Maritime safety
As a bulk cargo, bauxite is a Group A cargo that may liquefy if excessively moist. Liquefaction and the free surface effect can cause the cargo to shift rapidly inside the hold and make the ship unstable, potentially sinking the ship. One vessel suspected to have been sunk in this way was the MS Bulk Ju... | Bauxite | Wikipedia | 453 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
Red mud is a highly alkaline sludge, with a high pH around 13, that is a byproduct of the Bayer process. It contains several elements such as sodium aluminoscilicate, calcium titanate, monohydrate aluminium, and trihydrate aluminium that do not break down in nature. When improperly stored, red mud can contaminate soil ... | Bauxite | Wikipedia | 335 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
Ghana
The Atewa range in Ghana, classified as an ecologically important forest reserve with an area of , has been is a recent site of conflict and controversy surrounding baxuite mining. The forest reserve is one of the only two upland evergreen forests in Ghana, and makes up a significant portion of the remaining 20%... | Bauxite | Wikipedia | 387 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
Vietnam
In early 2009, the Vietnamese Government proposed a plan to mine remote regions of the central highlands. This proposal was highly controversial and sparked a nationwide debate and the most significant domestic conflict since the Vietnam War. Government scientists, journalists, religious leaders, retired high ... | Bauxite | Wikipedia | 385 | 3760 | https://en.wikipedia.org/wiki/Bauxite | Physical sciences | Petrology | null |
A book is a medium for recording information in the form of writing or images. Modern books are typically in codex format, composed of many pages that are bound together and protected by a cover; they were preceded by several earlier formats, including the scroll and the tablet. The book publishing process is the serie... | Book | Wikipedia | 462 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Definitions
In its modern incarnation, a book is typically composed of many pages (commonly of paper, parchment, or vellum) that are bound together along one edge and protected by a cover. By extension, book refers to a physical book's written, printed, or graphic contents. A single part or division of a longer writte... | Book | Wikipedia | 458 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
The history of books became an acknowledged academic discipline in the 1980s. Contributions to the field have come from textual scholarship, codicology, bibliography, philology, palaeography, art history, social history and cultural history. It aims to demonstrate that the book as an object, not just the text contained... | Book | Wikipedia | 481 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Tablet
Some of the earliest written records were made on tablets. Clay tablets (flattened pieces of clay impressed with a stylus) were used in the Ancient Near East throughout the Bronze Age and well into the Iron Age, especially for writing in cuneiform. Wax tablets (pieces of wood covered in a layer of wax) were use... | Book | Wikipedia | 382 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
The first written mention of the codex as a form of book is from Martial, in his Apophoreta CLXXXIV at the end of the first century, where he praises its compactness. However, the codex never gained much popularity in the pagan Hellenistic world, and only within the Christian community did it gain widespread use. This ... | Book | Wikipedia | 471 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
The rise of universities in the 13th century led to an increased demand for books, and a new system for copying appeared. The books were divided into unbound leaves (pecia), which were lent out to different copyists, so the speed of book production was considerably increased. The system was maintained by secular statio... | Book | Wikipedia | 426 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
19th century to present
Steam-powered printing presses became popular in the early 19th century. These machines could print 1,100 sheets per hour, but workers could only set 2,000 letters per hour. Monotype and linotype typesetting machines were introduced in the late 19th century. They could set more than 6,000 lette... | Book | Wikipedia | 454 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Modern books are organized according to a particular format called the book's layout. Although there is great variation in layout, modern books tend to adhere to a set of rules with regard to what the parts of the layout are and what their content usually includes. A basic layout will include a front cover, a back cove... | Book | Wikipedia | 345 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
The size of a book is generally measured by the height against the width of a leaf, or sometimes the height and width of its cover. A series of terms commonly used by contemporary libraries and publishers for the general sizes of modern books ranges from folio (the largest), to quarto (smaller) and octavo (still smalle... | Book | Wikipedia | 443 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Today, the majority of books are printed by offset lithography. When a book is printed, the pages are laid out on the plate so that after the printed sheet is folded the pages will be in the correct sequence. Books tend to be manufactured nowadays in a few standard sizes. The sizes of books are usually specified as "tr... | Book | Wikipedia | 492 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Recent developments in book manufacturing include the development of digital printing. Book pages are printed, in much the same way as an office copier works, using toner rather than ink. Each book is printed in one pass, not as separate signatures. Digital printing has permitted the manufacture of much smaller quantit... | Book | Wikipedia | 449 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Finishing
"Making cases" happens off-line and prior to the book's arrival at the binding line. In the most basic case-making, two pieces of cardboard are placed onto a glued piece of cloth with a space between them into which is glued a thinner board cut to the width of the spine of the book. The overlapping edges of ... | Book | Wikipedia | 511 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
In some markets, the sale of printed books has decreased due to the increased use of ebooks. However, printed books still largely outsell ebooks, and many people have a preference for print.
Dummy books
Dummy books (or faux books) are books that are designed to imitate a real book by appearance to deceive people, so... | Book | Wikipedia | 504 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Non-fiction books are in principle based on fact, encompassing subjects such as history, politics, social and cultural issues, as well as autobiographies and memoirs. Nearly all academic literature is non-fiction.
Reference
Reference books are non-fiction books intended to be quickly referred to for information, rat... | Book | Wikipedia | 483 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Address books, phone books, and calendar/appointment books are commonly used for recording appointments, meetings and personal contact information. Businesses historically used accounting books such as journals and ledgers to record financial data in a practice called bookkeeping (now usually held on computers rather t... | Book | Wikipedia | 510 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
In 2011, the International Federation of Library Associations and Institutions (IFLA) created the International Standard Bibliographic Description (ISBD) in order to standardize descriptions in bibliographies and library catalogs. Each book is specified by an International Standard Book Number, or ISBN, which is meant ... | Book | Wikipedia | 512 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Classification systems
Bliss bibliographic classification (BC)
Chinese Library Classification (CLC)
Colon Classification
Dewey Decimal Classification (DDC)
Harvard-Yenching Classification
Library of Congress Classification (LCC)
New Classification Scheme for Chinese Libraries
Universal Decimal Classification (... | Book | Wikipedia | 374 | 3778 | https://en.wikipedia.org/wiki/Book | Technology | Media and communication | null |
Brassicaceae () or (the older) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leaves are simple (although are sometimes deeply incised), lack stipules, and ... | Brassicaceae | Wikipedia | 444 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Species belonging to the Brassicaceae are mostly annual, biennial, or perennial herbaceous plants, some are dwarf shrubs or shrubs, and very few vines. Although generally terrestrial, a few species such as water awlwort live submerged in fresh water. They may have a taproot or a sometimes woody caudex that may have few... | Brassicaceae | Wikipedia | 488 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Hybridisation is not unusual in Brassicaceae, especially in Arabis, Rorippa, Cardamine and Boechera. Hybridisation between species originating in Africa and California, and subsequent polyploidisation is surmised for Lepidium species native to Australia and New Zealand | Brassicaceae | Wikipedia | 57 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Inflorescence and flower
Flowers may be arranged in racemes, panicles, or corymbs, with pedicels sometimes in the axil of a bract, and few species have flowers that sit individually on flower stems that spring from the axils of rosette leaves. The orientation of the pedicels when fruits are ripe varies dependent on th... | Brassicaceae | Wikipedia | 377 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Ovary, fruit and seed
There is one superior pistil that consists of two carpels that may either sit directly above the base of the stamens or on a stalk. It initially consists of only one cavity but during its further development a thin wall grows that divides the cavity, both placentas and separates the two valves (a... | Brassicaceae | Wikipedia | 390 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Phytochemistry
Almost all Brassicaceae have C3 carbon fixation. The only exceptions are a few Moricandia species, which have a hybrid system between C3 and C4 carbon fixation, C4 fixation being more efficient in drought, high temperature and low nitrate availability. Brassicaceae contain different cocktails of dozens ... | Brassicaceae | Wikipedia | 459 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Relationships within the family
Early classifications depended on morphological comparison only, but because of extensive convergent evolution, these do not provide a reliable phylogeny. Although a substantial effort was made through molecular phylogenetic studies, the relationships within the Brassicaceae have not al... | Brassicaceae | Wikipedia | 438 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Ecology
Brassicaceae are almost exclusively pollinated by insects. A chemical mechanism in the pollen is active in many species to avoid selfing. Two notable exceptions are exclusive self-pollination in closed flowers in Cardamine chenopodifolia, and wind pollination in Pringlea antiscorbutica. Although it can be cros... | Brassicaceae | Wikipedia | 267 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Brassicaceae contain glucosinolates as well as myrosinases inside their cells. When the cell is damaged, the myrosinases hydrolise the glucosinolates, leading to the synthesis of isothiocyanates, which are compounds toxic to most animals, fungi and bacteria. Some insect herbivores have developed counter adaptations suc... | Brassicaceae | Wikipedia | 494 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Since its introduction in the 19th century, Alliaria petiolata has been shown to be extremely successful as an invasive species in temperate North America due, in part, to its secretion of allelopathic chemicals. These inhibit the germination of most competing plants and kill beneficial soil fungi needed by many plants... | Brassicaceae | Wikipedia | 463 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
This family includes important agricultural crops, among which many vegetables such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy, kohlrabi, and gai lan (Brassica oleracea), turnip, napa cabbage, mizuna, bok choy and rapini (Brassica rapa), rocket salad/arugula (Eruca sativa), garden... | Brassicaceae | Wikipedia | 504 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
Some species are useful as food plants for Lepidoptera, such as certain wild mustard and cress species, such as Turritis glabra and Boechera laevigata that are utilized by several North American butterflies.
Gallery | Brassicaceae | Wikipedia | 48 | 3794 | https://en.wikipedia.org/wiki/Brassicaceae | Biology and health sciences | Brassicales | null |
In probability theory and statistics, the binomial distribution with parameters and is the discrete probability distribution of the number of successes in a sequence of independent experiments, each asking a yes–no question, and each with its own Boolean-valued outcome: success (with probability ) or failure (with p... | Binomial distribution | Wikipedia | 493 | 3876 | https://en.wikipedia.org/wiki/Binomial%20distribution | Mathematics | Statistics and probability | null |
is monotone increasing for and monotone decreasing for , with the exception of the case where is an integer. In this case, there are two values for which is maximal: and . is the most probable outcome (that is, the most likely, although this can still be unlikely overall) of the Bernoulli trials and is called the ... | Binomial distribution | Wikipedia | 496 | 3876 | https://en.wikipedia.org/wiki/Binomial%20distribution | Mathematics | Statistics and probability | null |
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