Antimony

From Free net encyclopedia

Antimony is a chemical element in the periodic table that has the symbol Sb (L. Stibium) and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metal. Yellow and black antimony are unstable non-metals. Antimony is used in flame-proofing, paints, ceramics, enamels, a wide variety of alloys, electronics, and rubber.

1 Notable characteristics
2 Applications
3 History
4 Sources
5 Precautions
6 Compounds
7 References
8 See also
9 External links

[edit]

Notable characteristics

Antimony 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 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 expand on cooling.

Estimates of the abundance of antimony in the Earth's crust range from 0.2 to 0.5 ppm. Antimony is geochemically categorized as a chalcophile, occurring with sulfur and the heavy metals lead, copper, and silver.

[edit]

Applications

Antimony is increasingly being used in the semiconductor industry in the production of diodes, infrared detectors, and Hall-effect devices. As an alloy, this semi-metal greatly increases lead's hardness and mechanical strength. The most important use of antimony metal is as a hardener in lead for storage batteries. Other uses;

Batteries,
antifriction alloys,
type metal,
small arms and tracer bullets,
cable sheathing,
matches,
medicines,
plumbing ("lead-free" solder contains 5% Sb),
main and big-end bearings in internal combustion engines (as alloy).
used in the past to treat Schistosomiasis; nowadays Praziquantel is universally used.

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. Also, antimony sulfide is one of the ingredients of a modern match.

[edit]

History

Antimony was recognized in antiquity (3000 BC or earlier) in various compounds, and it was prized for its fine casting qualities.

According to the history of metallurgy the first description of the procedure to isolate the antimony is in the Italian book "De la pirotechnia" of 1540 of Vannoccio Biringuccio. This book precedes the more famous Latin book "De re metallica" of 1556 of Agricola, although the latter has been often incorrectly considered the discoverer of the metallic antimony.

According to the traditional history of western alchemy the metallic antimony was previously (with respect to Biringuccio) described by the Prior Basilius Valentinus in the Latin manuscript "Currus Triumphalis Antimonii" of about 1450, published, in the English translation "The triumphal chariot of antimony", only in 1604 by Johann Thölde (1565-1614). The marvellous finding of all of the Valentinus' manuscripts, as in the alchemical tales, is fully described by Jean-Jacques Manget in his "Bibliotheca chemica curiosa" (1702): these manuscripts remained more than one century enclosed in a pillar of the St. Peter's Abbey, at Erfurt, until the pillar was miraculously shattered by a thunderbolt. Many authors consider Basilius Valentinus as a mythological personage: the most authoritative of them is Leibniz (1646-1716), that declared to be sure, after a careful search, that the Prior Valentinus did not ever exist in the Abbey of Erfurt, but was only a pseudonym, probably just of Thölde himself, that badly translated and merged materials of various origins.

According to the traditional history of Middle Eastern alchemy, the 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 the antimony is never quoted in them, but other authors claim that Berthelot translated only some of the less important books, while the more interesting ones (some of them perhaps well describing the antimony) are not yet translated, and their content is completely unknown.

The origin of the name "antimony" is not clear; the term may come from the Greek words "anti" and "monos", which approximately means "opposed to solitude" as it was thought never to exist in its pure form, or from the Pharaonic expression "Antos Amun", which could be translated as "bloom of the god Amun".

Image:Antimony-symbol.png

The natural sulfide of antimony, stibnite, was known and used in Biblical times as medicine and as a cosmetic. 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 severalveterinary 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.

The relationship between antimony's modern name and its symbol is complex; the Coptic name for the cosmetic powder antimony sulfide was borrowed by the Greeks, which was in turn borrowed by Latin, resulting in stibium. The chemical pioneer Jöns Jakob Berzelius used an abbreviation of this name for antimony in his writings, and his usage became the standard symbol.

Treatments chiefly involving antimony have been called antimonials.

[edit]

Sources

Image:Antimony massive.jpg Even though this element is not abundant, it is found in over 100 mineral species. Antimony is sometimes found native, but more frequently it is found in the sulfide stibnite (Sb₂S₃) which is the predominant ore mineral. Commercial forms of antimony are generally ingots, broken pieces, granules, and cast cake. Other forms are powder, shot, and single crystals.

Country	Tonnes	% of total
People's Republic of China	126 000	81.5
Russia	12 000	7.8
South Africa	5 023	3.3
Tadjikistan	3 480	2.3
Bolivia	2 430	1.6
Top 5	148 933	96.4
Total world	154 538	100.0

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.

[edit]

Precautions

Antimony 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. Such small doses have in the past been reported in some acidic fruit drinks. The acidic nature of the drink is sufficient to dissolve small amounts of antimony oxide contained in the packaging of the drink; modern manufacturing methods prevent this occurrence. Larger doses cause violent and frequent vomiting, and will lead to death in few days. Very large doses will cause violent vomiting, causing the poison to be expelled from the body before any harm is done.

See also arsenic poisoning.

[edit]