Name antimony
Symbol Sb
Atomic Weight 121.760
Atomic Number 51
CAS ID 7440-36-0
Group Number 15
Group Name Pnictogen
Period Number 5
Origin of Name Greek, anti + monos = "not alone", Latin, "stibium."
Year Discovered Prehistoric
Discovery Credits Probably known to the ancients and certainly to the alchemists.
Class Semi-Metallic
Color Silvery Lustrous Gray
Standard State Solid at 77 F & 298 K
Description Metalloid element with various allotropes, of which metal is bright, silvery, hard, and brittle. Stable in dry air and not attacked by dilute acids of alkalis. Used to harden other metals, in storage batteries, bearings, etc.

Diagnostic tests:
Antimony is usually detected by the coating of oxide formed by roasting on charcoal or the opentube.

Antimonides, antimony, etc. (As2-):  A sample of the powdered mineral gives off a dense sublimate of Sb2O3 when roasted on charcoal without the arsenic odor.  In the open tube test, they give a white, volatile, crystalline sublimate of Sb2O3 at a much higher temperature than arsenic. In the closed tube test with sulfur, they yield a  black sublimate when hot and red or reddish brown when cold.

Antimonates (SbO4): can be detected by lack of a garlic odor (arsenic) and the white sublimate yielded when a mixture of the powdered mineral with charcoal dust and Na2CO3 is heated with a reducing flame on a charcoal block.

Back to Elements Table Page