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

/ 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

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.

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

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.

From Wall Street Journal