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thorium

[ thawr-ee-uhm, thohr- ]

noun

, Chemistry.
  1. a grayish-white, lustrous, somewhat ductile and malleable, radioactive metallic element present in monazite: used as a source of nuclear energy, as a coating on sun-lamp and vacuum-tube filament coatings, and in alloys. : Th; : 232.038; : 90; : 11.7.


thorium

/ ˈθɔːrɪəm /

noun

  1. a soft ductile silvery-white metallic element. It is radioactive and occurs in thorite and monazite: used in gas mantles, magnesium alloys, electronic equipment, and as a nuclear power source. Symbol: Th; atomic no: 90; atomic wt: 232.0381; half-life of most stable isotope, 232Th: 1.41 × 10 10years; valency: 4; relative density: 11.72; melting pt: 1755°C; boiling pt: 4788°C


thorium

/ thôrē-əm /

  1. 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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Derived Forms

  • ˈthoric, adjective

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Other Words From

  • thor·ic [thawr, -ik, thor, -], adjective

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Word History and Origins

Origin of thorium1

< New Latin (1829); Thor, -ium

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Word History and Origins

Origin of thorium1

C19: New Latin, from Thor + -ium

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Example Sentences

This is a crucial step toward building a thorium nuclear clock.

It measured the energy of other jumps the thorium nucleus can make and subtracted them.

Its abundances of certain heavy elements such as thorium and uranium were higher than would be expected from a neutron star merger.

Recent measurements have more precisely pinpointed the energy of that jump, a crucial step toward building a thorium nuclear clock.

A variety of thorium called thorium-229 has a pair of energy levels close enough in energy that a laser could potentially set off the jump.

He was also the person who first identified silicon, selenium, thorium, and serium.

One of my assistants was demonstrating a peculiar property of thorium and Deverill seemed interested.

A million bucks of thorium with a hundred years of life in it—have a heart, mister!

The precipitate is thorium oxalate, which is washed with hot water, dried, and ignited.

Cones of zirconia are also used in the same way; or a thorium mantle in conjunction with alcohol vapour may be employed.

However, as we have seen, the view that thorium gives rise to stable lead is beset with some difficulties.

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thoritethorium dioxide