Thorium definition

thôrē-əm
A radioactive silvery-white metallic element that is recovered commercially from monazite. Its longest-lived isotope, the only one that occurs naturally, is Th-232 with a half-life of 14.1 billion years and is used as a nuclear fuel. Thorium is used in magnesium alloys, and its oxide is widely used in gas mantles of Welsbach burners. Atomic number 90; atomic weight 232.038; melting point 1,750°C; boiling point 4,788°C; specific gravity 11.72; valence 4.
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A rare, grayish, radioactive, metallic chemical element, one of the actinides, found in monazite and thorite: it is used in magnesium alloys, the making of gas mantles, electronic equipment, etc., and as a nuclear fuel: symbol, Th; at. no. 90
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A silvery-white, radioactive metallic element of the actinide series. It is used for fuel in some nuclear reactors and for improving the high-temperature strength of magnesium alloys. The only naturally occurring isotope of thorium, Th 232, is also its most stable, having a half-life of 14.1 billion years. Atomic number 90; atomic weight 232.038; approximate melting point 1,750°C; approximate boiling point 4,500°C; approximate specific gravity 11.7; valence 4.
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A chemical element (symbol Th) with atomic number 90.
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(physics) A radioactive isotope of thorium, 22890Th, having a half-life of 1.4 x 1010 years; it occurs naturally, and is a source of nuclear energy.
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Origin of thorium

  • After Thor

    From American Heritage Dictionary of the English Language, 5th Edition

  • After Thor.

    From Wiktionary

Thorium Sentence Examples

  • With Three Hours' Exposure He Found The Thorium Emanation Only From 3 To 5% Of The Whole, But With 12 Hours' Exposure The Percentage Of Thorium Emanation Rose To About 15.

  • In two cases, however, it has been found in the absence of appreciable quantities of uranium and thorium compounds, namely in beryl, and in sylvine (potassium chloride).

  • In 1824 he obtained zirconium from potassium zirconium fluoride; the preparation of (impure) titanium quickly followed, and in 1828 he obtained thorium.

  • In its chemical relations, titanium is generally tetravalent, and occurs in the same sub-group of the periodic classification as zirconium, cerium and thorium.

  • Within these limits are to be found most of the minerals known - gold, silver, quicksilver, copper, lead, zinc, iron, manganese, wolfram, bismuth, thorium, vanadium; mica, coal, &c. On or near the coast are coal, salt, sulphur, borax, nitrates and petroleum.

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