from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A very hard and brittle, exceptionally corrosion-resistant, whitish-yellow metallic element occurring in platinum ores and used principally to harden platinum and in high-temperature materials, electrical contacts, and wear-resistant bearings. Atomic number 77; atomic weight 192.2; melting point 2,410°C; boiling point 4,130°C; specific gravity 22.42 (at 17°C); valence 3, 4. See Table at element.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A metallic chemical element (symbol Ir) with an atomic number of 77.

from the GNU version of the Collaborative International Dictionary of English

  • n. A rare metallic element of atomic number 77, of the same group as platinum, which it much resembles, being silver-white and indifferent to most corrosive agents, but harder, more brittle, and with a higher melting temperature (2410° C, versus platinum 1772° C). With the exception of osmium, it is the heaviest substance known, its specific gravity being 22.4. Symbol Ir. Atomic weight 192.22.

from The Century Dictionary and Cyclopedia

  • n. Chemical symbol, Ir; atomic weight, 193. A metal of silver-white color, belonging to the platinum family, and, so far as known, always present in native platinum.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a heavy brittle metallic element of the platinum group; used in alloys; occurs in natural alloys with platinum or osmium


from The American Heritage® Dictionary of the English Language, 4th Edition

From Latin īris, īrid-, rainbow (from the colors produced by dissolving it in hydrochloric acid); see irido- + -ium.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Ancient Greek ἶρις ("rainbow") (because of the bright colour of many of iridium's salts).


  • The more common thicker photovoltaics contain iridium and other rare and expensive materials.


  • Maganda ba? mga sir, ito po ang cdi na gamit ko ngyn. .naka iridium nako at blue thunder ignition coil. .pero bkit parang wala akong na-feel na dagdag power or speed?

    Motorcycle Philippines

  • Ionizing radiation can also come from industrially produced radioactive materials (such as iridium-192); nuclear medicine (such as thyroid cancertreatment with iodine-131 and thyroid scans using iodine-125, or bone scans using technetium-99m); biological and medical research using carbon-14, tritium, and phosphorus-32; the nuclear fuel cycle (producing fission products such as cesium-137 and activation products such as cobalt-60); and production and testing of nuclear weapons.

    Public Health Statement for Ionizing Radiation

  • Scientists last year reported the discovery of five types of nano-diamonds along with impact material such as iridium and magnetic microspherules in the Younger Dryas impact layer,

    The Unreasonable Man

  • "They indicate there was an extra-terrestrial event on Earth 12,900 years ago .." impact material such as iridium and magnetic microspherules - as well as an NY Times report.

    Slugger O'Toole

  • Hundreds of pounds of gold, dozens of tons of copper, not to mention substantial amounts of other rare and precious metals such as iridium ... this glittering haul comes from recycled cell phones and the Japanese government is pleased as punch since Japan must import many of these metals.

    Inventor Spot - Inventions, Innovations, and Interesting Ideas for the Inventor in All of Us

  • Spark plugs must also be durable enough to be used in engine combustion chambers and materials such as iridium and platinum have been used to satisfy these conditions.

    The Earth Times Online Newspaper

  • Within its iridium shell, its brain verged on panic.

    Archive 2010-04-01

  • It's a cylinder of platinum-iridium about 39mm high, 39mm in diameter, cast by Johnson Matthey in Hatton Garden in 1879, delivered to the International Committee on Weights and Measures in Sevres shortly afterwards, polished and adjusted to be made equal in mass to the mass of the old French kilogram of the archives which dates from the time of the French Revolution.

    Royal Society meets to weigh up the shrinking kilogram

  • World Wide Mind 4. The University of Arkansas reported in 2008 that it had developed nanowires consisting of a core of gold fiber surrounded by iridium oxide.

    World Wide Mind


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  • Ir.

    December 16, 2007