thulium

American  

[thoo-lee-uhm] / ˈθu li əm /

noun

Chemistry.

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

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thulium British  

/ 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

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thulium Scientific  

/ tho̅o̅′lē-əm /

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

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Etymology

Origin of thulium

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

Example Sentences

Heavy rare-earth elements include dysprosium, terbium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium.

From Barron's

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

From Reuters

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.

From Seattle Times

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.

From Reuters

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

From Washington Times