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