| Element | Iridium |
| Symbol | Ir |
| Atomic Mass | 192.22 |
| Atomic Number | 77 |
| Name Origins | Latin, Iris = rainbow |
| Year Discovered | 1803 |
| Discovered Credits | Discovered by S. Tennant at London, UK. |
| Remarks | Hard, 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 Tests | There 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. |
| References | Emsley, 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) :
| Chengdeite | 91.17 % | Ir3Fe |
| Cuproiridsite | 66.71 % | CuIr2S4 |
| Kashinite | 66.13 % | (Ir,Rh)2S3 |
| Rutheniridosmine | 63.20 % | (Ir,Os,Ru) |
| Tolovkite | 55.55 % | IrSbS |
| Iridium | 52.58 % | (Ir,Os,Ru,Pt) |
| Inaglyite | 46.99 % | PbCu3(Ir,Pt)8S16 |
| Iridarsenite | 45.15 % | (Ir,Ru)As2 |
| Changchengite | 44.37 % | IrBiS |
| Shuangfengite | 42.96 % | IrTe2 |
| Ruthenium | 41.99 % | (Ru,Ir,Os) |
| Iridisite | 41.22 % | (Ir,Cu,Rh,Ni,Pt)S2 |
| Mayingite | 36.35 % | IrBiTe |
| Gaotaiite | 36.10 % | Ir3Te8 |
| Xingzhongite | 35.73 % | (Pb,Cu,Fe)(Ir,Pt,Rh)2S4 |
| Hexaferrum | 31.11 % | (Fe,Os,Ru,Ir) |
| Irarsite | 30.24 % | (Ir,Ru,Rh,Pt)AsS |
| Bowieite | 29.84 % | (Rh,Ir,Pt)1.77S3 |
| Osmium | 25.20 % | (Os,Ir) |
| Malanite | 16.56 % | Cu(Pt,Ir)2S4 |
| Ferrorhodsite | 10.58 % | (Fe,Cu)(Rh,Ir,Pt)2S4 |
| Konderite | 9.57 % | PbCu3(Rh,Pt,Ir)8S16 |