ElementOsmium
SymbolOs
Atomic Mass190.2
Atomic Number76
Name OriginsGreek, osme = smell
Year Discovered1803
Discovered CreditsDiscovered by S. Tennant at London, UK.
RemarksLustrous 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 TestsThere 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.
ReferencesEmsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.

Naturally Ocurring Isotopes :

Mass Nuclide Number Natural Abundance Half-life Half-life Unit Decay Mode Decay Mode MeV Decay Mode %
183.952488 184 0.02 % Stable
185.95383 186 1.58 % 2x1015 Years alpha 100,0
186.955741 187 1.6 % Stable
187.95586 188 13.3 % Stable
188.958137 189 16.1 % Stable
189.958436 190 26.4 % Stable
191.961476 192 41 % Stable

9 Minerals sorted by % of Os (Osmium) :

Osmium74.80 %(Os,Ir)
Erlichmanite74.78 %OsS2
Osarsite51.89 %(Os,Ru)AsS
Omeiite44.89 %(Os,Ru)As2
Rutheniridosmine31.27 %(Ir,Os,Ru)
Iridium31.22 %(Ir,Os,Ru,Pt)
Hexaferrum17.59 %(Fe,Os,Ru,Ir)
Anduoite17.41 %(Ru,Os)As2
Ruthenium13.85 %(Ru,Ir,Os)