Antimony Sb

Discovery

Stibnite, antimony sulfide, has been known since antiquity. Ancient Egyptians ground it into a black powder used as kohl to darken the eyes.

The element itself may have been produced early on, but it was long confused with lead. In 1540 the Italian metallurgist Vannoccio Biringuccio described how to extract antimony in his book De la pirotechnia, and in the seventeenth century chemists such as the Frenchman Nicolas Lémery studied its compounds systematically.

In medieval and early modern Europe antimony compounds were widely used as emetics. Wine left standing in a cup made of antimony would make the drinker vomit, and because the cup lost almost nothing with each use, such "perpetual pills" and cups could be reused for generations.

Origin of the name

The name comes from the medieval Latin antimonium, whose origin is uncertain. A popular folk etymology claims it means "against monks", but there is no evidence for this. The symbol Sb comes from stibium, the Latin name for stibnite.

Main uses

• Flame retardants: antimony trioxide greatly boosts the effect of halogenated flame retardants in cable insulation, electronics housings and textiles; this is its largest use.
• Lead-acid batteries: antimony hardens lead for battery grids.
• Type metal: lead–tin–antimony alloy expands slightly as it solidifies, filling moulds precisely and producing crisp printing type.
• Plastics catalyst: it catalyses the production of PET resin.
• Semiconductors and medicine: antimony is an n-type dopant for silicon, indium antimonide is used in infrared detectors, and some antimony compounds treat leishmaniasis, a parasitic disease.

Isotopes

Natural antimony consists of two stable isotopes, antimony-121 (about 57%) and antimony-123 (about 43%). Radioactive antimony-124 (half-life about 60 days) and antimony-125 (about 2.8 years) form in nuclear reactors and are tracked in radiation monitoring.

In everyday life

China produces the most antimony, followed by countries such as Russia and Tajikistan. Because supply is concentrated in a few countries, many governments list it as a critical mineral.

Antimony and its compounds resemble arsenic and are toxic. Swallowing large amounts causes vomiting and diarrhoea, and long-term inhalation of dust can harm the lungs and skin. Studies have found that trace antimony can leach from PET bottles, but under normal conditions levels are reported to be far below drinking-water limits. Even so, it is sensible not to leave PET bottles in hot places for long periods.