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The pentahalides SbF
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5 have trigonal bipyramidal molecular geometry in the gas phase , but in the liquid phase , SbF
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5 is polymeric , whereas SbCl
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5 is monomeric . SbF
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5 is a powerful Lewis acid used to make the <unk> <unk> acid ( " <unk> " ) .
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Oxyhalides are more common for antimony than arsenic and phosphorus . Antimony trioxide dissolves in concentrated acid to form <unk> compounds such as <unk> and ( SbO )
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= = = <unk> , hydrides , and organoantimony compounds = = =
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Compounds in this class generally are described as derivatives of Sb3 − . Antimony forms antimonides with metals , such as indium antimonide ( <unk> ) and silver antimonide ( Ag
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<unk> ) . The alkali metal and zinc antimonides , such as <unk> and <unk> , are more reactive . Treating these antimonides with acid produces the unstable gas stibine , <unk>
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Sb3 − + 3 H + → <unk>
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<unk> can also be produced by treating Sb3 + salts with hydride reagents such as sodium <unk> decomposes spontaneously at room temperature . Because stibine has a positive heat of formation , it is thermodynamically unstable and thus antimony does not react with hydrogen directly .
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<unk> compounds are typically prepared by alkylation of antimony halides with Grignard reagents . A large variety of compounds are known with both Sb ( III ) and Sb ( V ) centers , including mixed chloro @-@ organic derivatives , anions , and cations . Examples include Sb ( C6H5 ) 3 ( <unk> ) , Sb2 ( C6H5 ) 4 ( with a... | wikitext |
= = History = =
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Antimony ( III ) sulfide , Sb2S3 , was recognized in predynastic Egypt as an eye cosmetic ( kohl ) as early as about 3100 BC , when the cosmetic palette was invented .
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An artifact , said to be part of a vase , made of antimony dating to about 3000 BC was found at <unk> , Chaldea ( part of present @-@ day Iraq ) , and a copper object plated with antimony dating between 2500 BC and 2200 BC has been found in Egypt . Austen , at a lecture by Herbert Gladstone in 1892 commented that " we... | wikitext |
<unk> was unconvinced the artifact was indeed a vase , mentioning that <unk> , after his analysis of the Tello object ( published in 1975 ) , " attempted to relate the metal to Transcaucasian natural antimony " ( i.e. native metal ) and that " the antimony objects from Transcaucasia are all small personal ornaments . ... | wikitext |
The Roman scholar Pliny the Elder described several ways of preparing antimony sulfide for medical purposes in his treatise Natural History . Pliny the Elder also made a distinction between " male " and " female " forms of antimony ; the male form is probably the sulfide , while the female form , which is superior , h... | wikitext |
The Roman naturalist Pedanius Dioscorides mentioned that antimony sulfide could be roasted by heating by a current of air . It is thought that this produced metallic antimony .
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The first description of a procedure for isolating antimony is in the book De la <unk> of 1540 by Vannoccio Biringuccio ; this predates the more famous 1556 book by Agricola , De re metallica . In this context Agricola has been often incorrectly credited with the discovery of metallic antimony . The book <unk> <unk> <... | wikitext |
The metal antimony was known to German chemist Andreas Libavius in 1615 who obtained it by adding iron to a molten mixture of antimony sulfide , salt and potassium tartrate . This procedure produced antimony with a crystalline or starred surface .
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With the advent of challenges to phlogiston theory it was recognized that antimony is an element forming sulfides , oxides , and other compounds , as is the case with other metals .
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The first natural occurrence of pure antimony in the Earth 's crust was described by the Swedish scientist and local mine district engineer Anton von <unk> in 1783 ; the type @-@ sample was collected from the Sala Silver Mine in the <unk> mining district of Sala , <unk> , Sweden .
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= = = Etymology = = =
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The ancient words for antimony mostly have , as their chief meaning , kohl , the sulfide of antimony .
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The Egyptians called antimony <unk> ; in hieroglyphs , the vowels are uncertain , but there is an Arabic tradition that the word is <unk> <unk> . The Greek word , <unk> stimmi , is probably a loan word from Arabic or from Egyptian <unk>
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and is used by Attic tragic poets of the 5th century BC ; later Greeks also used <unk> <unk> , as did Celsus and Pliny , writing in Latin , in the first century AD . Pliny also gives the names <unk> [ sic ] , <unk> , alabaster , and the " very common " <unk> , " wide @-@ eye " ( from the effect of the cosmetic ) . Lat... | wikitext |
The use of Sb as the standard chemical symbol for antimony is due to Jöns Jakob Berzelius , who used this abbreviation of the name stibium . The medieval Latin form , from which the modern languages and late Byzantine Greek take their names for antimony , is antimonium . The origin of this is uncertain ; all suggestio... | wikitext |
Another popular etymology is the hypothetical Greek word <unk> <unk> , " against aloneness " , explained as " not found as metal " , or " not found unalloyed " . Lippmann conjectured a hypothetical Greek word <unk> <unk> , which would mean " <unk> " , and cites several examples of related Greek words ( but not that on... | wikitext |
The early uses of antimonium include the translations , in 1050 – 1100 , by Constantine the African of Arabic medical treatises . Several authorities believe antimonium is a scribal corruption of some Arabic form ; <unk> derives it from <unk> ; other possibilities include <unk> , the Arabic name of the metalloid , and... | wikitext |
= = Production = =
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= = = Top producers and production volumes = = =
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The British Geological Survey ( BGS ) reported that in 2005 , China was the top producer of antimony with an approximately 84 % world share , followed at a distance by South Africa , Bolivia and Tajikistan . <unk> Mine in Hunan province has the largest deposits in China with an estimated deposit of 2 @.@ 1 million met... | wikitext |
In 2010 , according to the US Geological Survey , China accounted for 88 @.@ 9 % of total antimony production with South Africa , Bolivia and Russia sharing the second place .
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However , Roskill Consulting estimates for primary production show that in 2010 China held a 76 @.@ 75 % share of world supply with 120 @,@ 462 tonnes ( 90 @,@ 000 tonnes of reported and 30 @,@ 464 tonnes of un @-@ reported production ) , followed by Russia ( 4 @.@ 14 % share , 6 @,@ 500 tonnes of production ) , Myanm... | wikitext |
Roskill estimates that secondary production globally in 2010 was 39 @,@ 540 tonnes .
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Antimony was ranked first in a Risk List published by the British Geological Survey in the second half of 2011 . The list provides an indication of the relative risk to the supply of chemical elements or element groups required to maintain the current British economy and lifestyle .
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Also , antimony was identified as one of 12 critical raw materials for the EU in a report published in 2011 , primarily due to the lack of supply outside China .
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Reported production of antimony in China fell in 2010 and is unlikely to increase in the coming years , according to the Roskill report . No significant antimony deposits in China have been developed for about ten years , and the remaining economic reserves are being rapidly depleted .
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The world 's largest antimony producers , according to Roskill , are listed below :
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= = = Reserves = = =
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According to statistics from the USGS , current global reserves of antimony will be depleted in 13 years . However , the USGS expects more resources will be found .
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= = = Production process = = =
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The extraction of antimony from ores depends on the quality of the ore and composition of the ore . Most antimony is mined as the sulfide ; lower @-@ grade ores are concentrated by froth flotation , while higher @-@ grade ores are heated to 500 – 600 ° C , the temperature at which stibnite melts and is separated from ... | wikitext |
3 + 3 Fe → 2 Sb + 3 FeS
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The sulfide is converted to an oxide and advantage is often taken of the volatility of antimony ( III ) oxide , which is recovered from roasting . This material is often used directly for the main applications , impurities being arsenic and sulfide . Isolating antimony from its oxide is performed by a carbothermal red... | wikitext |
3 + 3 C → 4 Sb + 3 CO
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The lower @-@ grade ores are reduced in blast furnaces while the higher @-@ grade ores are reduced in reverberatory furnaces .
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= = Applications = =
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About 60 % of antimony is consumed in flame retardants , and 20 % is used in alloys for batteries , plain bearings and solders .
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= = = Flame retardants = = =
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Antimony is mainly used as its trioxide in making flame @-@ proofing compounds . It is nearly always used in combination with halogenated flame retardants , with the only exception being in halogen @-@ containing polymers . The formation of halogenated antimony compounds is the cause for the flame retarding effect of ... | wikitext |
= = = Alloys = = =
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Antimony forms a highly useful alloy with lead , increasing its hardness and mechanical strength . For most applications involving lead , varying amounts of antimony are used as alloying metal . In lead – acid batteries , this addition improves the charging characteristics and reduces generation of unwanted hydrogen d... | wikitext |
= = = Other applications = = =
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Three other applications make up nearly all the rest of the consumption . One of these uses is as a stabilizer and a catalyst for the production of <unk> . Another application is to serve as a fining agent to remove microscopic bubbles in glass , mostly for TV screens ; this is achieved by the interaction of antimony ... | wikitext |
Antimony is being increasingly used in the semiconductor industry as a dopant for heavily doped n @-@ type silicon wafers in the production of diodes , infrared detectors , and Hall @-@ effect devices . In the 1950s , tiny beads of a lead @-@ antimony alloy were used to dope the emitters and collectors of n @-@ p @-@ ... | wikitext |
Few biological or medical applications exist for antimony . Treatments principally containing antimony are known as <unk> and are used as <unk> . Antimony compounds are used as <unk> drugs . Potassium <unk> tartrate , or tartar emetic , was once used as an anti @-@ <unk> drug from 1919 on . It was subsequently replace... | wikitext |
Antimony @-@ based drugs , such as <unk> <unk> , are also considered the drugs of choice for treatment of leishmaniasis in domestic animals . Unfortunately , as well as having low therapeutic indices , the drugs are poor at penetrating the bone marrow , where some of the Leishmania amastigotes reside , and so cure of ... | wikitext |
In the heads of some safety matches , antimony ( III ) sulfide is used . Antimony @-@ 124 is used together with beryllium in neutron sources ; the gamma rays emitted by antimony @-@ 124 initiate the photodisintegration of beryllium . The emitted neutrons have an average energy of 24 keV . Antimony sulfides have been s... | wikitext |
Antimony also is used in the making of bullets and bullet tracers . This element is also used in paint and glass art crafts and as opacifier in enamel .
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= = Precautions = =
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The effects of antimony and its compounds on human and environmental health differ widely . The massive antimony metal does not affect human and environmental health . Inhalation of antimony trioxide ( and similar poorly soluble Sb ( III ) dust particles such as antimony dust ) is considered harmful and suspected of c... | wikitext |
For oral absorption , <unk> ( 1994 ) recommended values of 10 % for tartar emetic and 1 % for all other antimony compounds . Dermal absorption for metals is estimated at most 1 % ( <unk> , 2007 ) . Inhalation absorption of antimony trioxide and other poorly soluble Sb ( III ) substances ( such as antimony dust ) is es... | wikitext |
Antimony is mainly excreted from the human body via urine . Antimony and its compounds do not cause acute human health effects , with the exception of antimony potassium tartrate ( " tartar emetic " ) , a prodrug that is intentionally used to treat leishmaniasis patients .
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Prolonged skin contact with antimony dust may cause dermatitis . However , it was agreed at the European Union level that the skin rashes observed are not substance @-@ specific , but most probably due to a physical blocking of sweat ducts ( ECHA / PR / 09 / 09 , Helsinki , 6 July 2009 ) . Antimony dust may also be ex... | wikitext |
Antimony is incompatible with strong acids , halogenated acids , and oxidizers ; when exposed to newly formed hydrogen it may form stibine ( SbH3 ) .
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The 8 hour time weighted average ( TWA ) is set at 0 @.@ 5 mg / m3 by the American Conference of Governmental Industrial Hygienists and by the Occupational Safety and Health Administration ( OSHA ) as a legal permissible exposure limit ( PEL ) in the workplace . The National Institute for Occupational Safety and Healt... | wikitext |
World Health Organization : 20 µg / L
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Japan : 15 µg / L
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United States Environmental Protection Agency , Health Canada and the Ontario Ministry of Environment : 6 µg / L
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EU and German Federal Ministry of Environment : 5 µg / L
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The TDI proposed by WHO is 6 µg antimony per kilogram of body weight . The IDLH ( immediately dangerous to life and health ) value for antimony is 50 mg / m3 .
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= Mortimer Wheeler =
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Sir Robert Eric Mortimer Wheeler CH , CIE , MC , TD , FSA , FRS , FBA ( 10 September 1890 – 22 July 1976 ) was a British archaeologist and officer in the British Army . Over the course of his career , he served as Director of both the National Museum of Wales and London Museum , Director @-@ General of the Archaeologi... | wikitext |
Born in Glasgow to a middle @-@ class family , Wheeler was raised largely in Yorkshire before relocating to London in his teenage years . After studying Classics at University College London ( UCL ) , he began working professionally in archaeology , specializing in the Romano @-@ British period . During World War I he... | wikitext |
In 1934 , he established the Institute of Archaeology as part of the federal University of London , adopting the position of Honorary Director . In this period , he oversaw excavations of the Roman sites at Lydney Park and Verulamium and the Iron Age hill fort of Maidan Castle . During World War II , he re @-@ joined ... | wikitext |
Wheeler is recognised as one of the most important British archaeologists of the twentieth century , responsible for successfully encouraging British public interest in the discipline and advancing methodologies of excavation and recording . Further , he is widely acclaimed as a major figure in the establishment of So... | wikitext |
= = Early life = =
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= = = Childhood : 1890 – 1907 = = =
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Mortimer Wheeler was born on 10 September 1890 in the city of Glasgow , Scotland . He was the first child of the journalist Robert Mortimer Wheeler and his second wife Emily Wheeler ( née Baynes ) . The son of a tea merchant based in Bristol , in youth Robert had considered becoming a Baptist minister , but instead be... | wikitext |
When Wheeler was four , his father was appointed chief leader writer for the Bradford Observer . The family relocated to Saltaire , a village northwest of Bradford , a cosmopolitan city in Yorkshire , northeast England , which was then in the midst of the wool trade boom . Wheeler was inspired by the moors surrounding... | wikitext |
In 1899 , Wheeler joined Bradford Grammar School shortly before his ninth birthday , where he proceeded straight to the second form . In 1902 Robert and Emily had a second daughter , whom they named Betty ; Mortimer showed little interest in this younger sister . In 1905 , Robert agreed to take over as head of the Lon... | wikitext |
= = = University and early career : 1907 – 14 = = =
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After passing the entrance exam on his second attempt , in 1907 Wheeler was awarded a scholarship to read classical studies at University College London ( UCL ) , commuting daily from his parental home to the university campus in Bloomsbury , central London . At UCL , he was taught by the prominent classicist A. E. Ho... | wikitext |
Wheeler began studying for a Master of Arts degree in classical studies , which he attained in 1912 . During this period , he also gained employment as the personal secretary of the UCL Provost Gregory Foster , although he later criticised Foster for transforming the university from " a college in the truly academic s... | wikitext |
During his studies , Wheeler had developed his love of archaeology , having joined an excavation of Viroconium Cornoviorum , a Romano @-@ British settlement in Wroxeter , in 1913 . Considering a profession in the discipline , he won a studentship that had been established jointly by the University of London and the So... | wikitext |
At this period , there were very few jobs available within British archaeology ; as the later archaeologist Stuart Piggott related , " the young Wheeler was looking for a professional job where the profession had yet to be created . " In 1913 Wheeler secured a position as junior investigator for the English Royal Comm... | wikitext |
= = = First World War : 1914 – 18 = = =
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After the United Kingdom 's entry into World War I in 1914 , Wheeler volunteered for the armed forces . Although preferring solitary to group activities , Wheeler found that he greatly enjoyed soldiering . For the next seven months , he was posted as an instructor in the University of London Officer Training Corps . I... | wikitext |
In October 1917 Wheeler was posted to the 76th Army Field Artillery Brigade , one of the Royal Field Artillery brigades under the direct control of the General Officer Commanding , Third Army . The brigade was then stationed in Belgium , where it had been engaged in the Battle of Passchendaele against German troops al... | wikitext |
Wheeler and the brigade arrived in Italy on 20 November , and proceeded through the Italian Riviera to reach Caporetto , where it had been sent to bolster the Italian troops against a German and Austro @-@ Hungarian advance . As the Russian Republic removed itself from the war , the German Army refocused its efforts o... | wikitext |
= = Career = =
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= = = National Museum of Wales : 1919 – 26 = = =
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On returning to London , Wheeler moved into a top @-@ floor flat near Gordon Square with his wife and child . He returned to working for the Royal Commission , examining and cataloguing the historic structures of Essex . In doing so , he produced his first publication , an academic paper on Colchester 's Roman <unk> G... | wikitext |
He obtained a post as the Keeper of Archaeology at the National Museum of Wales , a job that also entailed becoming a lecturer in archaeology at the University College of South Wales and Monmouthshire . Taking up this position , he moved to Cardiff with his family in August 1920 , although he initially disliked the ci... | wikitext |
Wheeler was impatient to start excavations , and in July 1921 started a six @-@ week project to excavate at the Roman fort of Segontium ; accompanied by his wife , he used up his holiday to oversee the project . A second season of excavation at the site followed in 1922 . Greatly influenced by the writings of the arch... | wikitext |
Over the field seasons of 1924 and 1925 , Wheeler ran excavations of the Roman fort of Y Gaer near Brecon , a project aided by his wife and two archaeological students , Nowell Myres and Christopher Hawkes . During this project , he was visited by the prominent Egyptologist Sir Flinders Petrie and his wife Hilda Petri... | wikitext |
In 1924 , the Director of the National Museum of Wales , William Evans Hoyle , resigned amid ill health . Wheeler applied to take on the role of his replacement , providing supportive testimonials from Charles Reed Peers , Robert Bosanquet , and H. J. Fleure . Although he had no prior museum experience , he was succes... | wikitext |
= = = London Museum : 1926 – 33 = = =
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Upon the retirement of the Keeper of the London Museum , Harmon Oates , Wheeler was invited to fill the vacancy . He had been considering a return to London for some time and eagerly agreed , taking on the post , which was based at Lancaster House in the St James 's area , in July 1926 . In Wales , many felt that Whee... | wikitext |
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