Encyclopedia
| Antimony
Encyclopedia
|
| Tutorials | Encyclopedia | Dictionary | Directory |
|
Antimony
Antimony (IPA [ć?nt?m??ni?] (Received Pronunciation), /?ćnt
PropertiesAntimony in its elemental form is a silvery white, brittle, fusible, crystalline solid that exhibits poor electrical and heat conductivity properties and vaporizes at low temperatures. A metalloid, antimony resembles a metal in its appearance and in many of its physical properties, but does not chemically react as a metal. It is also attacked by oxidizing acids and halogens. Antimony and some of its alloys are unusual in that they expand on cooling. Antimony is geochemically categorized as a chalcophile, occurring with sulfur and the heavy metals lead, copper, and silver. Estimates of the abundance of antimony in the Earth's crust range from 0.2 to 0.5 ppm. ApplicationsAntimony is increasingly being used in the semiconductor industry in the production of diodes, infrared detectors, and Hall-effect devices. As an alloy, this metalloid greatly increases lead's hardness and mechanical strength. The most important use of antimony is as a hardener in lead for storage batteries. Uses include:
Antimony compounds in the form of oxides, sulfides, sodium antimonate, and antimony trichloride are used in the making of flame-proofing compounds, ceramic enamels, glass, paints, and pottery. Antimony trioxide is the most important of the antimony compounds and is primarily used in flame-retardant formulations. These flame-retardant applications include such markets as children's clothing, toys, aircraft and automobile seat covers. It is also used in the fiberglass composites industry as an additive to polyester resins for such items as light aircraft engine covers. The resin will burn while a flame is held to it but will extinguish itself as soon as the flame is removed. Antimony sulfide is also one of the ingredients of safety matches. In the 1950s, tiny beads of a lead-antimony alloy were used for the emitters and collectors of NPN alloy junction transistors. The natural sulfide of antimony, stibnite, was known and used in Biblical times, as medicine and in Islamic/Pre-Islamic times as a cosmetic. The Sunan Abi Dawood reports, ?Muhammad said: 'Among the best types of collyrium you use is antimony (ithmid) for it clears the vision and makes the hair sprout.'?[1] Stibnite is still used in some developing countries as medicine. Antimony has been used for the treatment of schistosomiasis. Antimony attaches itself to sulfur atoms in certain enzymes which are used by both the parasite and human host. Small doses can kill the parasite without causing damage to the patient. Antimony and its compounds are used in several veterinary preparations like Anthiomaline or Lithium antimony thiomalate, which is used as a skin conditioner in ruminants. Antimony has a nourishing or conditioning effect on keratinized tissues, at least in animals. Tartar emetic is another antimony preparation which is used as an anti-schistosomal drug. Treatments chiefly involving antimony have been called antimonials. Antimony-based drugs such as Allopurinol, and Meglumine, are also considered the drugs of choice for the 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 the disease - especially the visceral form - is very difficult. A coin made of antimony was issued in the Keichow Province of China in 1931. The coins were not popular, being too soft and they wore quickly when in circulation. After the first issue no others were produced.[2] EtymologyThe ancient words for antimony mostly have, as their chief meaning, kohl, the sulfide of antimony. Pliny the Elder, however, distinguishes between male and female forms of antimony; his male form is probably the sulfide, the female form, which is superior, heavier, and less friable, is probably native metallic antimony.[3] The Egyptians called antimony m?dmt; in hieroglyphics, the vowels are uncertain, but there is an Arabic tradition that the word is mesdemet.[4] The Greek word, stimmi, is probably a loan word from Arabic or Egyptian, and is used by the Attic tragic poets of the 5th century BC; later Greeks also used stibi, as did Celsus and Pliny, writing in Latin, in the first century AD. Pliny also gives the names stimi [sic], larbaris, alabaster, and the "very common" platyophthalmos, "wide-eye" (from the effect of the cosmetic). Later Latin authors adapted the word to Latin as stibium. The Arabic word for the substance, as opposed to the cosmetic, can appear as ithmid, athmoud, othmod, or uthmod. Littré suggests the first form, which is the earliest, derives from stimmida, (one) accusative for stimmi.[5] The use of Sb as the standard chemical symbol for antimony is due to the 18th century chemical pioneer, Jöns Jakob Berzelius, who used this abbreviation of the name stibium. 
The early uses of antimonium include the translations, in 1050-1100, by Constantine the African of Arabic medical treatises.[9] Several authorities believe that antimonium is a scribal corruption of some Arabic form; Meyerhof derives it from ithmid;[10] other possibilities include Athimar, the Arabic name of the metal, and a hypothetical *as-stimmi, derived from or parallel to, the Greek.[11] History
One of the alchemical symbols for antimony. An artifact made of antimony dating to about 3000 BC was found at Tello, 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.[13] There is some uncertainty as to the description of the artifact from Tello. Although it is sometimes reported to be a vase, a recent detailed discussion of it reports it to be rather a fragment of indeterminate purpose.[14] Antimony was first isolated by Geber (721-815), a Persian(or Arab) alchemist.[15] The first European description of a procedure for isolating antimony is in the book De la pirotechnia of 1540 by Vannoccio Biringuccio, written in Italian. This book precedes the more famous 1556 book in Latin by Agricola, De re metallica, even though Agricola has been often incorrectly credited with the discovery of metallic antimony. 
Another alchemical symbol for antimony According to the traditional history of Middle Eastern alchemy, pure antimony was well known to Geber, sometimes called "the Father of Chemistry", in the 8th century. Here there is still an open controversy: Marcellin Berthelot, who translated a number of Geber's books, stated that antimony is never mentioned in them, but other authors claim that Berthelot translated only some of the less important books, while the more interesting ones (some of which might describe antimony) are not yet translated, and their content is completely unknown. The first natural occurence of pure antimony ('native antimony') in the Earth's crust was described by the Swedish scientist and local mine district engineer Anton von Swab in 1783. The type-sample was collected from the Sala Silver Mine in the Bergslagen mining district of south central Sweden. Sources
Native massive antimony with oxidation products 
Antimony output in 2005 
World production trend of antimony In 2005, China was the top producer of antimony with about 84% world share followed at a distance by South Africa, Bolivia and Tajikistan, reports the British Geological Survey.
Chiffres de 2003, métal contenue dans les minerais et concentrés, source: L'état du monde 2005 The largest mine in China is Xikuangshan mine in Hunan Province. See also Antimonide minerals, Antimonate minerals. PrecautionsAntimony and many of its compounds are toxic. Clinically, antimony poisoning is very similar to arsenic poisoning. In small doses, antimony causes headache, dizziness, and depression. Larger doses cause violent and frequent vomiting, and will lead to death in a few days. See also arsenic poisoning. A study[16][17] found that antimony may be leaching from PET bottled water, but at levels below drinking water guidelines. The guidelines are:
The acidic nature of the drink is sufficient to dissolve small amounts of antimony trioxide contained in the packaging of the drink; modern manufacturing methods prevent this occurrence. However, researchers are concerned that antimony levels correspond to duration the bottle is left to stand - the longer the beverage has been bottled, the higher the antimony leached. CompoundsSee also Antimony compounds. Important compounds of antimony include:
See alsoReferencesBibliography
External links
af:Antimoon ar:???? az:Stibium bs:Antimon bg:??????? ca:Antimoni cs:Antimon co:Antimoniu cy:Antimoni da:Antimon de:Antimon et:Antimon el:????????? es:Antimonio eo:Antimono eu:Antimonio fa:???????? fr:Antimoine fur:Antimoni ga:Antamón gv:Antimoan gl:Antimonio ko:???? hy:????? hi:????????? hr:Antimon io:Antimonio id:Antimon is:Antimon it:Antimonio he:??????? jv:Antimon pam:Antimony ht:Antimwŕn ku:Stîbyűm la:Stibium lv:Antimons lb:Antimon lt:Stibis jbo:antimoni hu:Antimon ml:???????? mr:???????? nl:Antimoon ja:????? no:Antimon nn:Antimon oc:Antimňni uz:Surma nds:Antimon pl:Antymon pt:Antimônio ro:Stibiu qu:Antimunyu ru:?????? scn:Antimoniu simple:Antimony sk:Antimón sl:Antimon sr:??????? sh:Antimon fi:Antimoni sv:Antimon ta:?????????? th:???? vi:Antimon tg:????? tr:Antimon uk:?????? (???????? ???????) ur:??? zh-yue:? zh:? Source: Wikipedia | The above article is available under the GNU FDL. | Edit this article
|
|
top
©2008-2009 TutorGig.com. All Rights Reserved. Privacy Statement
