Definitions

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

  • adj. Spontaneously igniting in air.
  • adj. Producing sparks by friction.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. spontaneously igniting in air, especially when in a finely divided state
  • adj. producing sparks, especially by friction
  • adj. Able to oxidize with exposure to atmospheric oxygen at normal temperatures.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Light-producing; of or pertaining to pyrophorus.

from The Century Dictionary and Cyclopedia

  • Same as pyrophorous.

Etymologies

From pyrophorus, substance that ignites spontaneously : from Greek purophoros, fire-bearing : puro-, pyro- + -phoros, -phorous.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek πυροφόρος ("fire-bearing") +‎ -ic. (Wiktionary)

Examples

  • The company got a chance to show that when a customer had an accidental release of a "pyrophoric" gas that can ignite on contact with air.

    China Slowdown Stunts Entrepreneurs

  • Depleted uranium is "pyrophoric", which makes it uniquely effective at piercing hard targets, because upon impact, it immediately burns, vaporizing the majority of its bulk and leaving a hard, thin, sharpened tip - and large amounts of radioactive particles suspended in the atmosphere.

    Honor Vets by Learning About Depleted Uranium

  • Finely divided uranium powder is pyrophoric, meaning it will ignite spontaneously at room temperature.

    About.com Chemistry

  • Uranium in its pure form is a silver-colored heavy metal that is nearly twice as dense as lead and is pyrophoric when finely divided.

    Uranium

  • Finely divided uranium metal, being pyrophoric, presents a fire hazard.

    Uranium

  • A bit more about DU – When fired or exploded, it is pyrophoric, becoming a tremendous fiery explosion, and reaches high temperatures between 3,000-6,000 degrees Centigrade.

    No More DU, No More Hiroshimas, No More Nagasakis

  • Due to the pyrophoric nature of uranium metal and the extreme temperatures generated on impact of depleted uranium ammunition on a hard target, it ignites and produces an aerosol of fine particles of uranium oxides if the temperature exceeds 600°C.

    Depleted uranium

  • Raney-Ni is known to be a very active catalyst for hydrogenation and a pyrophoric material, indeed a dangerous one to be handled with care that has on occasion exploded.

    Rabett Run

  • It turns out the uranium from nuclear waste is very dense and possesses pyrophoric properties.

    Archive 2008-03-01

  • The pyrophoric nature of depleted uranium, which causes it to begin to burn at very low temperatures from friction in the gun barrel, made it an ideal radioactive gas weapon then and now.

    International Doctors for D.U. (Depleted Uranium)

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Comments

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  • So is this another way to describe spontanious combustion?

    September 27, 2010