Name osmium
Symbol Os
Atomic Weight 190.23
Atomic Number 76
CAS ID 7440-04-2
Group Number 8
Group Name Precious Metal
Period Number 6
Origin of Name Greek, osme = "smell."
Year Discovered 1803
Discovery Credits Discovered by S. Tennant at London, UK.
Class Metallic
Color Bluish Gray
Standard State Solid at 77 F & 298 K
Description Lustrous silvery metal of the platinum group. Unaffected by air, water, and acids, but dissolves in molten alkalis. Smells, due to formation of volatile OsO4. Used in alloys and catalysts.

Diagnostic tests: 
There are no simple chemical tests for osmium. The element is usually found as an alloy or a sulfide mineral with other platinum group metals. Atomic Absorption Spectroscopy is used for quantitative analysis and Energy Dispersive Analysis of X-rays (EDAX) is used for qualitative analysis.

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