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

  • n. See thorium dioxide.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The rare earth, thorium oxide.

from the GNU version of the Collaborative International Dictionary of English

  • n. A rare white earthy substance, consisting of the oxide of thorium; -- formerly called also thorina.

from The Century Dictionary and Cyclopedia

  • n. The name was first given by Berzelius to a supposed new earth announced by him in 1815 as present in xenotime and other Swedish or Norwegian minerals. He afterward proved that this material was in fact yttrium phosphate. In 1828 he discovered a really distinct earth in tine mineral thorite, and applied to it the same name (from the god Thor of Scandinavian mythology), and in this sense the word is used. This earth the oxid of thorium, forms the principal part of the mautles of Welsbach incandescent gas-lamps The material used has been varied, with a view to securing as white a light as possible, but is said to be commonly about 99 per cent. of thorium oxid and 1 per cent of cerium oxid.
  • n. An oxid of thorium, ThO2.


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

From thorium.

from Wiktionary, Creative Commons Attribution/Share-Alike License

New Latin. See thorite.


  • Thorium oxide (ThO2), also called thoria, has one of the highest melting points of all oxides (3300°C).


  • At the same temperature of 350°C amyl alcohol vapour yields valeric aldehyde and hydrogen with copper, and amylene and water with thoria.

    Paul Sabatier - Nobel Lecture

  • I liken the part played by thoria in respect of the alcohols to that of sulphuric acid in the classical mechanism, known as Williamson's method, for the production of diethyl ether or ethylene.

    Paul Sabatier - Nobel Lecture

  • When in contact with thoria, and without any apparent modification in this latter substance, the vapours of the alcohols react directly with hydrogen sulphide to give thiols, with ammonia to give primary amines, with primary amines to give secondary amines, with phenols to give mixed oxides and with fatty acids to give esters of these acids; these reactions may find important industrial applications.

    Paul Sabatier - Nobel Lecture

  • Other authorities hold that mantles for acetylene, should contain other rare earths besides the thoria and ceria of which the coal-gas mantles almost wholly consist.

    Acetylene, the Principles of Its Generation and Use

  • The light of any combustible consumed on the "incandescent" system is derived from glowing particles of ceria, thoria, or similar metallic oxides; and the character or shade of the light they emit is a function, apart from the temperature to which they are raised, of their specific chemical nature.

    Acetylene, the Principles of Its Generation and Use

  • The specific gravity of pure thoria is 10.2207 to 10.2198.

    Scientific American Supplement, No. 365, December 30, 1882

  • Chloride tungsten or titanium passed through hot tube, depositing a film of metal on the carbon; or filaments of zirconia oxide, or alumina or magnesia, thoria or other infusible oxides mixed or separate, and obtained by moistening and squirting through a die, are thus coated with above metals and used for incandescent lamps.

    Edison, His Life and Inventions, vol. 2

  • The best sands (highest in thoria) came from Burke and Cleveland counties, though some of special high grade has been reported from McDowell county.

    North Carolina and its Resources.

  • Dissolve; and from the hydrochloric acid solution precipitate the thoria (if any) with ammonium oxalate.

    A Text-book of Assaying: For the Use of Those Connected with Mines.


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