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 [[ | + | 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]]. An alloy of 90% [[platinum]] and 10% iridium is widely used in both the jewelry and chemical industries, because it is strong, hard, beautiful, and impervious to almost all chemicals even at very high temperatures. |
A layer of iridium in certain rocks, found all over the world, is part of the evidence implying that an asteroid strike caused the [[Cretaceous-Tertiary Mass Extinction]]. | A layer of iridium in certain rocks, found all over the world, is part of the evidence implying that an asteroid strike caused the [[Cretaceous-Tertiary Mass Extinction]]. | ||
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- Electrical contacts. | - Electrical contacts. | ||
| + | |||
| + | |||
| + | ==See also== | ||
| + | * [[Precious metal]] | ||
| + | * [[Gold]] and [[Silver]] | ||
| + | * [[Gold standard]] | ||
| + | * [[Inflation hedge]] | ||
| + | * [[Fiat currency]] | ||
| + | |||
| + | ==References== | ||
| + | {{reflist|2}} | ||
| + | |||
| + | {{Periodic table}} | ||
[[Category:Elements]] | [[Category:Elements]] | ||
| − | + | [[Category:Metals]] | |
| + | [[Category:Precious Metals]] | ||
Latest revision as of 05:25, July 12, 2016
| 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. An alloy of 90% platinum and 10% iridium is widely used in both the jewelry and chemical industries, because it is strong, hard, beautiful, and impervious to almost all chemicals even at very high temperatures.
A layer of iridium in certain rocks, found all over the world, is part of the evidence implying that an asteroid strike caused the Cretaceous-Tertiary Mass Extinction.
Uses
Iridium does not have many "everyday" uses, but a few common ones are:
- Spark plugs.
- Phonograph needles.
- It forms an alloy with osmium used for tipping pens and compass bearings.
- Electrical contacts.
See also
References
| Periodic Table of the Elements | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |||||||
77
Ir 192.2 |
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| *Lanthanides | ||||||||||||||||||||||||
| **Actinides | ||||||||||||||||||||||||
