Difference between revisions of "Iridium"
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'''Iridium''' is an [[element]] in the [[transition metal]]s class of the [[periodic table of the elements|periodic table]]. It is hard and lustrous, and is perhaps the most corrosion-resistant metal known. It has the second-highest density of all elements, after [[osmium]]. | '''Iridium''' is an [[element]] in the [[transition metal]]s class of the [[periodic table of the elements|periodic table]]. It is hard and lustrous, and is perhaps the most corrosion-resistant metal known. It has the second-highest density of all elements, after [[osmium]]. | ||
| − | An alloy of [[platinum]] and iridium was used in the international standard [[meter]] bar, before the standard was changed in 1960. A similar alloy is still used in the international standard [[kilogram]]. | + | An alloy of [[platinum]] and iridium was used in the international standard [[International_System_of_Units#Meter|meter]] bar, before the standard was changed in 1960. A similar alloy is still used in the international standard [[International_System_of_Units#Kilogram|kilogram]]. |
[[Category:Elements]] | [[Category:Elements]] | ||
Revision as of 03:34, November 27, 2008
| Iridium | |
|---|---|
| Properties | |
| Atomic symbol | Ir |
| Atomic number | 77 |
| Classification | Transition Metals |
| Atomic mass | 192.22 amu |
| Number of Stable Isotopes | 2 |
| Density (grams per cc) | 22.560 g/cm^3 |
| Other Information | |
| Date of discovery | 1803 |
| Name of discoverer | Smithson Tennant |
| Name origin | From the Latin iridis, meaning rainbow. |
| Uses | Used in conjunction with osmium to tip gold pen points, to make crucibles and other high-temperature containers. Also used to make alloys for standard weights and measures, as well as heat-resistant alloys. In addition, used in cancer irradiation, hypodermic needles, helicopter spark plugs and as hardening agent for platinum. |
| Obtained from | Found in gravel deposits with platinum, iridosmium, and osmiridium ores. |
Iridium is an element in the transition metals class of the periodic table. It is hard and lustrous, and is perhaps the most corrosion-resistant metal known. It has the second-highest density of all elements, after osmium.
An alloy of platinum and iridium was used in the international standard meter bar, before the standard was changed in 1960. A similar alloy is still used in the international standard kilogram.