Antimony

Category: metalloid Atomic number: 51 Colour: silvery Melting point: 631°C (1,167°F) Boiling point: 1,587°C (2,889°F) First identified: approx. 1600 BC

Antimony has been used in various forms for at least 5,000 years. An ancient fragment of an antimony artefact from the Sumerian civilization was found in the nineteenth century in what is now Iraq – it has sometimes been described as having been part of a vase, although this seems unlikely, as antimony is too brittle to be shaped into a vessel. The mineral stibnite (a black form of the pigment antimony sulphide) was used as mascara (known as khol) by the Egyptians by about 1600 BC. (The abbreviation Sb comes from stibium, the Latin name for stibnite.) In the biblical description of that infamous bad girl, Jezebel, she is said to have ‘painted her eyes with kohl and dressed her hair’ in a final act of defiance. The pigment yellow lead antimonite was also used by the Babylonians to glaze ornamental bricks.

In medieval times, antimony was best known for its supposed medicinal qualities: it is a rather toxic substance, but it was used as an emetic and as a laxative. The ‘Antimony War’ of the seventeenth century was a furious debate following the esteemed physician and alchemist Paracelsus’s enthusiasm for it. One German writer, masquerading as a monk called ‘Basil Valentine’, advocated its many uses in a book called The Triumphal Chariot of Antimony. He admitted it was poisonous, claiming the name came from ‘anti-monk’ – as it was known for poisoning monks – but at the same time claimed he could make a non-toxic version using alchemy. It has also been suggested that medicines made from the element may have killed the composer Mozart.

Antimony is mainly used today in the electronics industry (for instance, in semiconductors, diodes and, alloyed with indium, infrared detectors). It can be alloyed with soft metals such as lead to make them harder; was traditionally used in pewter, where the copper and antimony together hardened the tin and lead; and an alloy of lead and antimony can be used to make bullets or type metal (as found in old-fashioned printing presses). It is also used in a variety of flame-retardant materials such as paints and enamels.