Stibnite

Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb₂S₃. It forms grey orthorhombic crystals of hardness 2. It is the most important source for the rare metaloid antimony.

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Formation and structure

Stibnite is formed from antimony(III) compounds with hydrogen sulfide. This reaction gives a black precipitate:

2 Sb³⁺ + 3 H₂S → Sb₂S₃ + 6 H⁺

This reaction is reversed by hydrochloric acid.

Stibnite is attacked by potassium hydroxide solution and dissolves in solutions of polysulfide ions to give polysulfido complexes.^[1] Related reactions were once used in university courses on qualitative inorganic analysis.

Stibnite has a structure similar to that of As₂S₃. The Sb(III) centers, which are pyramidal and three-coordinate, are linked via bent two-coordinate sulfide ions.

Uses

Stibnite is used to make fireworks, metal antifriction alloys, and batteries.^[2] It was used as mascara by Queen Jezebel of the Old Testament (2 Kings 9,30) and is an ingredient of safety matches.^{[citation needed]}

Occurrence

Small deposits of stibnite are common; large deposits are rare. It occurs in Canada, Mexico, Peru, Japan, China, Germany, Romania, Italy, France, England, Algeria, and Kalimantan, Borneo. In the United States it is found in Arkansas, Idaho, Nevada, California, and Alaska. Large iridescent stibnite crystals are found in Japan.^{[citation needed]}

  As of May 2007, the largest specimen on public display (1000 pounds) is at the American Museum of Natural History.^[3]

See also

• List of minerals

References