promethium

[ pruh-mee-thee-uhm ]

noun

, Chemistry.

1. a rare-earth, metallic, trivalent element. : Pm; : 61.

promethium

/ prəˈmiːθɪəm /

noun

1. 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, ¹⁴⁵Pm: 17.7 years; valency: 3; melting pt: 1042°C; boiling pt: 2460°C (approx.)

promethium

/ prə-mē′thē-əm /

1. 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.
2. See Periodic Table

Word History and Origins

Origin of promethium¹

From New Latin, dating back to 1945–50; Prometheus, -ium

Word History and Origins

Origin of promethium¹

C20: New Latin from Prometheus