promethium

American  

[pruh-mee-thee-uhm] / prəˈmi θi əm /

noun

Chemistry.

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

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promethium British  

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

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promethium Scientific  

/ 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

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Etymology

Origin of promethium

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

Example Sentences

At ORNL, promethium was synthesized at the High Flux Isotope Reactor, a DOE Office of Science user facility, and purified at the Radiochemical Engineering Development Center, a multipurpose radiochemical processing and research facility.

From Science Daily • May 22, 2024

The production, purification and preparation of the promethium sample were supported by the DOE Isotope Program, managed by the Office of Science for Isotope R&D and Production.

From Science Daily • May 22, 2024

The 17 elements are: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.

From Reuters • Jul. 5, 2023

Experimenting with elements created by the Manhattan Project, researchers realized that they could create two different versions, or isotopes, of promethium, the sixty-first atom on the periodic table.

From The New Yorker • Dec. 27, 2019

Compare the resonance of einsteinium and promethium to chromosome 7 and chromosome 21.

From Slate • Jul. 9, 2012