An Overview about the Chemical Element Antimony


Symbol: Sb

Atomic Number: 51

Atomic Mass: 121.76 amu (atomic mass units)

Melting Point: 630.0 C (903.15 K, 1166.0 F)

Boiling Point: 1750.0 C (2023.15 K, 3182.0 F)

Number of Protons: 51

Number of Electrons: 51

Number of Neutrons: 71

Classification: Metalloid

Group Name: Pnictogen

Crystal Structure: Rhombohedral

Density @ 293 K: 6.684 grams per cubic centimeter

Color: silver/gray

Antimony has been known to man for thousands of years. The Egyptians used the stibnite, a mineral that contains antimony, as a black makeup used for outlining the eyes. The French chemist Nicolas Lemery made the first scientific study of the element and its compounds, which he published in 1707. The element’s name comes from the Greek words “anti” and “monos”, put together these words mean “not alone”. The symbol “Sb” is from the element’s historic name “stibnium”.

Pure antimony is a very brittle semi metal. It is a poor conductor of both electricity and heat. When heated in a flame antimony burns with a brilliant flame and gives of white fumes. The element makes up 0.00002% of the earth’s crust.

Antimony and all of its compounds are toxic and are capable of causing severe damage to the liver if ingested. Despite this, at one time, antimony compounds were used in medicine. They were used to induce either vomiting or sweating. Antimony chloride was a weapon of last resort in the treatment of cancerous growths and poisoned wounds. Fortunately, antimony is no longer used in medicine as it as been superseded by far safer alternatives.

There are two naturally occurring isotopes of antimony, both of which are stable. These isotopes are antimony-121 (57.21%) and antimony-123 (42.79%). Other, unstable, isotopes of antimony are known with mass numbers in the range of 103 to 139.

A small amount of antimony is as a free element in nature. Some antimony is produced as a by-product from the smelting of gold, silver, copper and lead. The majority of commercially produced antimony comes from mineral ores. The principal mineral ores from which antimony is extracted are stibnite and valentinite. Three quarters of the world’s supply of this element comes from mines in China

The element, in pure form (99.999% pure), is used in the production of semiconductor devices such as diodes and infrared radiation detectors. When alloyed to lead it increases the metal’s durability. Lead and other antimony alloys are used to make batteries, low friction metals and protective sheathing for cables. Type metal used to make the type for printing presses is an alloy of lead, antimony and tin.

Compounds containing antimony are used in the production of many items including paints, ceramics, glass and pottery. They can also be used to make flameproofing materials.