Antimon

Antimon

Antimony is a chemical element with the 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. 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 soldiering, cable sheaths, and ammunition.

Properties

Antimony is a member of group 15 of the periodic table, one of the elements called pnictogens, and has an electronegativity of 2.05. According to the Pauling scale, it is relatively stable in air at room temperature, but it reacts with oxygen if heated to produce antimony trioxide, Sb2O3.

Physical Properties

Antimony is a silvery, lustrous gray metalloid with a Mohs scale hardness of 3, which is too soft to make hard objects; coins of antimony were issued in China's Guizhou province in 1931 but the durability was poor and the minting was soon discontinued. Antimony is resistant to attack by acids.

Chemical Properties

Antimony, like arsenic, exhibits both metallic and non-metallic characteristics. In its metallic form, antimony is brittle, hard, and has a poor electrical and thermal conductivity. Non-metallic antimony is a black powder. Antimony is a poor conductor of heat and electricity, especially in its non-metallic form.

Occurrence

Antimony is not abundant, but is found in over 100 mineral species. It is sometimes found native, but more frequently as the sulfide stibnite. The largest producers of antimony are China, Russia, and Tajikistan.

Compounds

Antimony forms a variety of compounds and has four oxidation states: -3, +3, +4, and +5. The most common and stable state is +3, in which antimony forms compounds such as antimony trioxide, antimony trisulfide, and antimony trichloride.

Uses

The primary use of antimony is in lead-acid batteries for vehicles. Other uses include flame retardants, as the sulfide in luminophores, in semiconductors, and in thermoelectric devices. Antimony compounds are also used in the textile industry, in fire retardants, and in paints, ceramics, and fireworks.

Health Effects

Exposure to antimony can occur in the workplace or from environmental sources. Antimony compounds can be toxic, especially if ingested or inhaled in large amounts. Long-term exposure can lead to antimony poisoning, symptoms of which include skin irritation, respiratory issues, and gastrointestinal problems. The International Agency for Research on Cancer (IARC) has not classified antimony as to its carcinogenicity to humans.

Environmental Impact

Antimony enters the environment during the mining and processing of its ores and in the production of antimony metal, alloys, antimony oxide, and combinations with other substances. Antimony can have harmful effects on the environment if it is released in significant quantities.