About Antimony

Name: Antimony
Symbol: Sb
Type: Metalloid, Nitrogen group
Atomic weight: 121.75
Density @ 293 K: 6.684 g/cm3
Atomic volume: 18.22 cm3/mol





Antimony ( stibium): is a chemical element with the symbol Sb and an atomic number of 51. A silvery lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds are prominent fire retardants found in many commercial and domestic products. Certain alloys are valuable for use in solders and ball bearings. An emerging application is the use of antimony in microelectronics. The relatively high toxicity of some antimony compounds, being similar to arsenic compounds, limits the applications. Certain compounds of antimony have been of fundamental value in chemistry, a prominent example being the development of super acids derived from antimony pentafluoride.


The name "antimony" is derived from two Greek words: 'anti' and 'monos' which mean not alone. This results from the fact that antimony is infrequently found native, but usually combined with sulfur or with heavier metals such as copper, lead and silver.


Discovered: The presence of antimony in historical artifacts indicates it was known to ancient civilizations. Combined with sulfur in stibnite (Sb2S3) it was used in Egyptian cosmetics four or five thousand years ago, as a black eyeliner.


It's likely that Roman author Pliny gave it the name stibium, from which the modern element symbol Sb was taken, in the first century AD. Stibnite is found most commonly, Pliny says, among the ores of silver. Pliny described stibnite's use as a medicine. He also noted how if too strongly heated, it would turn to lead. What we understand now by this is the lead described by Pliny is actually the element antimony.


In the first half of the 1500s, Vannoccio Biringuccio wrote a description "Concerning Antimony and Its Ore". This is an alchemical work. Biringuccio describes antimony sulfide as either "a monstrosity among metals" or, alternatively, "a material that is about to reach metallic perfection, but is hindered from doing so by being mined too soon". He also warns against heating the antimony sulfide too strongly because this will produce a substance that "although this is very white and almost more shining than silver, it is much more brittle than glass." This is a clear description of the element antimony.


Nicolas Lémery wrote his Treatise on Antimony in 1707. This was still not chemistry as we know it. In his writings, Lémery describes how acids prick the tongue because they contain spiky particles, while metals dissolve in acids because the sharp points of acids tear the metal particles apart.


Antimony is a soft metal (2 on mohs scale). A coin made of antimony issued in the Guizhou Province of China in 1931 was unpopular because they would wear out fast. After the first issue no others were produced. It is resistant to attack by acids.






Four allotropes of antimony are known: a stable metallic form, and three meta-stable forms which are: explosive, black and yellow. Metallic antimony is a brittle, silver-white shiny metal. When molten antimony is slowly cooled, metallic antimony crystallizes in an hexagonal cell, isomorphic with that of the black allotrope of arsenic.


A rare explosive form of antimony can be formed from the electrolysis of antimony(III) trichloride. When scratched with a sharp implement, an exothermic reaction occurs and white fumes given off as metallic antimony is formed; alternatively, when rubbed with a pestle in a mortar, a strong detonation occurs. Black antimony is formed when gaseous metallic antimony is rapidly cooled. It oxidizes in air and is sometimes spontaneously combustible. At 100 B0C, it gradually transforms into the stable form.


The yellow allotrope of antimony is the most unstable. It has only been generated by oxidation of stibine (SbH3) at −90 °C. Above this temperature and in ambient light, this meta stable allotrope transforms into the stabler black allotrope.[


Isotopes: Antimony exists as two stable isotopes, one with 70 neutrons, the other with 72.


Occurrence: The abundance of antimony in the Earth's crust is estimated at 0.2 to 0.5 parts per million, comparable to thallium at 0.5 parts per million and silver at 0.07 ppm. 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.


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. The mine with the largest deposits in China is Xikuangshan mine in Hunan Province with a estimated deposit of 2.1 million metric tons.

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