ElementIridium
SymbolIr
Atomic Mass192.22
Atomic Number77
Name OriginsLatin, Iris = rainbow
Year Discovered1803
Discovered CreditsDiscovered by S. Tennant at London, UK.
RemarksHard, lustrous, silvery metal of the platinum group. Stable to air and water, inert to all acids, but fused NaOH will attack it. Used in special alloys and spark plugs.
Diagnostic TestsThere are no simple chemical tests for iridium. 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 %
190.960584 191 37.3 % Stable
192.962917 193 62.7 % Stable

22 Minerals sorted by % of Ir (Iridium) :

Chengdeite91.17 %Ir3Fe
Cuproiridsite66.71 %CuIr2S4
Kashinite66.13 %(Ir,Rh)2S3
Rutheniridosmine63.20 %(Ir,Os,Ru)
Tolovkite55.55 %IrSbS
Iridium52.58 %(Ir,Os,Ru,Pt)
Inaglyite46.99 %PbCu3(Ir,Pt)8S16
Iridarsenite45.15 %(Ir,Ru)As2
Changchengite44.37 %IrBiS
Shuangfengite42.96 %IrTe2
Ruthenium41.99 %(Ru,Ir,Os)
Iridisite41.22 %(Ir,Cu,Rh,Ni,Pt)S2
Mayingite36.35 %IrBiTe
Gaotaiite36.10 %Ir3Te8
Xingzhongite35.73 %(Pb,Cu,Fe)(Ir,Pt,Rh)2S4
Hexaferrum31.11 %(Fe,Os,Ru,Ir)
Irarsite30.24 %(Ir,Ru,Rh,Pt)AsS
Bowieite29.84 %(Rh,Ir,Pt)1.77S3
Osmium25.20 %(Os,Ir)
Malanite16.56 %Cu(Pt,Ir)2S4
Ferrorhodsite10.58 %(Fe,Cu)(Rh,Ir,Pt)2S4
Konderite9.57 %PbCu3(Rh,Pt,Ir)8S16