Antimony (51)

Metallic antimony is an extremely brittle metal of a flaky, crystalline texture. It is bluish white and has a metallic luster. It is not acted on by air at room temperature, but burns brilliantly when heated with the formation of white fumes. It is a poor conductor of heat and electricity.

Antimony and its compounds are toxic. It is found mostly with other minerals and in stibnite.

•Name: Antimony
•Symbol: Sb
•Atomic number: 51
•Atomic weight: 121.760
•Standard state: solid at 298 K
•CAS Registry ID: 7440-36-0
•Group in periodic table: 15
•Group name: Pnictogen
•Period in periodic table: 5
•Block in periodic table: p-block
•Color: silvery lustrous grey
•Classification: Semi-metallic

Historical information

Antimony was discovered by Known since ancient times at no data in not known. Origin of name is from the Greek words "anti + monos" meaning "not alone" (the origin of the symbol Sb comes from the Latin word "stibium"). Antimony was recognized in compounds by the ancients and was known as a metal at the beginning of the 17th century and possibly much earlier. Its most important mineral is stibnite, a mineral which formed the basis of black eye makeup in Biblical times. Antimony was sometimes confused with lead in those times. It seems not to be clear who first recognized antimony as an element but the French chemist Nicolas Lémery conducted much of the earlier studies on antimony chemistry.

Antimony is one of the elements which has an alchemical symbol, which looks like an upside down 'female' symbol. Alchemy is an ancient pursuit concerned with, for instance, the transformation of other metals into gold.

Physical properties

•Melting point: 903.78 [or 630.63 °C (1167.13 °F)] K
•Boiling point: 1860 [or 1587 °C (2889 °F)] K
•Density of solid: 6697 kg m-3

Orbital properties

•Ground state electron configuration: [Kr].4d10.5s2.5p3
•Shell structure: 2.8.18.18.5
•Term symbol: 4S3/2

Isolation

It is not usually necessary to make antimony in the laboratory as it is commercially available. Antimony is found in nature in a number of minerals including stibnite (Sb2S3) and ullmanite (NiSbS). Small amounts of native antimony have been found. Some ores are treatable under reducing conditions to form Sb2S3. The sulfide is removed to leave elemental antimony with scrap iron.

Sb2S3 + 3Fe → 2Sb + 3FeS

In another process, some ores can be heated to evolve the oxide Sb2O3 and this in turn can be reduced by charcoal in the presence of sodium sulphate, to ensure mixing, to form elemental antimony.

2Sb2O3 +3C → 4Sb + 3CO2