promethium
[ pruh-mee-thee-uh m ]
/ prəˈmi θi əm /
noun Chemistry.
a rare-earth, metallic, trivalent element. Symbol: Pm; atomic number: 61.
Origin of promethium
From New Latin, dating back to 1945–50; see origin at
Prometheus,
-ium
Words nearby promethium
British Dictionary definitions for promethium
promethium
/ (prəˈmiːθɪəm) /
noun
a radioactive element of the lanthanide series artificially produced by the fission of uranium. Symbol: Pm; atomic no: 61; half-life of most stable isotope, 145 Pm: 17.7 years; valency: 3; melting pt: 1042°C; boiling pt: 2460°C (approx.)
Word Origin for promethium
C20: New Latin from
Prometheus
Medical definitions for promethium
promethium
[ prə-mē′thē-əm ]
n. Symbol Pm
A radioactive rare-earth element prepared by fission of uranium. Pm 145 is the longest-lived isotope with a half-life of 17.7 years. Atomic number 61.
Scientific definitions for promethium
promethium
[ prə-mē′thē-əm ]
Pm
A radioactive metallic element of the lanthanide series. Promethium does not occur in nature but is prepared through the fission of uranium. It has 17 isotopes, one of which is used to make long-lived miniature batteries that work at extreme temperatures for up to five years. The longest-lived isotope, Pm 147, has a half-life of 2.5 years and is used as a source of beta rays. Atomic number 61; melting point 1,168°C; boiling point 2,460°C; valence 3. See Periodic Table.