promethium

pro·me·thi·um  (pr-mth-m)

n. Symbol Pm

A radioactive rare-earth element prepared by fission of uranium or by neutron bombardment of neodymium, having 14 isotopes with mass numbers ranging from 141 to 154 and used as a source of beta rays. Atomic number 61; melting point 1,168°C; boiling point 2,460°C; valence 3. See Table at element.

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[From Prometheus.]

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promethium [prəˈmiːθɪəm]

n

(Chemistry / Elements & Compounds) 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.)

[New Latin from Prometheus]

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promethium  (pr-mth-m)

Symbol 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.

Thesaurus

Noun

1.

promethium - a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium atomic number 61, Pm metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

Translations

promethium

n (Chem) → Promethium nt