thulium

[thoo-lee-uhm]

noun

Chemistry.

1. a rare-earth metallic element found in the minerals euxenite, gadolinite, etc. Tm; 168.934; 69; 9.32.

thulium

/ ˈθjuːlɪəm /

noun

1. a malleable ductile silvery-grey element occurring principally in monazite. The radioisotope thulium-170 is used as an electron source in portable X-ray units. Symbol: Tm; atomic no: 69; atomic wt: 168.93421; valency: 3; relative density: 9.321; melting pt: 1545°C; boiling pt: 1950°C

thulium

1. A soft, silver-gray metallic element of the lanthanide series. One of its artificial radioactive isotopes is used as a radiation source in small, portable x-ray machines. Atomic number 69; atomic weight 168.934; melting point 1,545°C; boiling point 1,727°C; specific gravity 9.3; valence 2, 3.

2. See Periodic Table

Word History and Origins

Origin of thulium¹

From New Latin, dating back to 1875–80; Thule, -ium

Word History and Origins

Origin of thulium¹

C19: New Latin, from _Thule + _-ium

Example Sentences

The 17 elements are: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.

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Ultra Safe has explored different isotopes, like cobalt-60 and thulium, which can be scaled to produce 10 times the energy of traditional plutonium systems while beingsafer and more cost-effective.

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Rare earth metals are a group of 17 elements - lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium - that appear in low concentrations in the ground.

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Department of Energy has rated it and thulium as the elements in shortest supply in the nation.

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Rare-earth elements include the relatively common cerium, used in pollution-control equipment, and terbium, used in energy efficient light bulbs, as well as the truly rare thulium, which has applications in x-ray devices.

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