Antimony - Periodic Table of Videos

Antimony is a chemical element with symbol Sb (from Latin: stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb₂S₃). Antimony compounds have been known since ancient times and were used for cosmetics; metallic antimony was also known, but it was erroneously identified as lead upon its discovery. In the West, it was first isolated by Vannoccio Biringuccio and described in 1540, although in primitive cultures its powder has been used to cure eye ailments, as also for eye shadow, since time immemorial, and is often referred to by its Arabic name, kohl.^[3]
For some time, China has been the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan. The industrial methods to produce antimony are roasting and reduction using carbon or direct reduction of stibnite with iron.
The largest applications for metallic antimony are as alloying material for lead and tin and for lead antimony plates in lead–acid batteries. Alloying lead and tin with antimony improves the properties of the alloys which are used in solders, bullets and plain bearings. Antimony compounds are prominent additives for chlorine and bromine-containing fire retardants found in many commercial and domestic products. An emerging application is the use of antimony in microelectronics.
Antimony is in the nitrogen group (group 15) and has an electronegativity of 2.05. As expected from periodic trends, it is more electronegative than tin or bismuth, and less electronegative than tellurium or arsenic. Antimony is stable in air at room temperature, but reacts with oxygen if heated, to form antimony trioxide, Sb₂O₃.^[4]:758
Antimony is a silvery, lustrous gray metalloid that has a Mohs scale hardness of 3. Thus pure antimony is too soft to make hard objects; coins made of antimony were issued in China's Guizhou province in 1931, but because of their rapid wear, their minting was discontinued.^[5] Antimony is resistant to attack by acids.
Four allotropes of antimony are known: a stable metallic form and three metastable forms (explosive, black and yellow). Elemental antimony is a brittle, silver-white shiny metalloid. When slowly cooled, molten antimony crystallizes in a trigonal cell, isomorphic with the gray allotrope of arsenic. A rare explosive form of antimony can be formed from the electrolysis of antimony trichloride. When scratched with a sharp implement, an exothermic reaction occurs and white fumes are given off as metallic antimony is formed; when rubbed with a pestle in a mortar, a strong detonation occurs. Black antimony is formed upon rapid cooling of vapor derived from metallic antimony. It has the same crystal structure as red phosphorus and black arsenic, it oxidizes in air and may ignite spontaneously. At 100 °C, 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 metastable allotrope transforms into the more stable black allotrope.^[6][7][8]