thorium

[ thawr-ee-uhm, thohr- ]

Phonetic (Standard)IPA

noun

, Chemistry.

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 /

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

/ thôr′ē-əm /

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.
See Periodic Table

Origin of thorium¹

< New Latin (1829); Thor, -ium

Origin of thorium¹

C19: New Latin, from Thor + -ium

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.

Browse