promethium
Americannoun
noun
-
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
Etymology
Origin of promethium
From New Latin, dating back to 1945–50; see origin at Prometheus, -ium
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Using a research reactor, hot cells and supercomputers, as well as the accumulated knowledge and skills of 18 scientists in different fields, the authors detailed the first observation of a promethium complex in solution.
From Science Daily ● May 22, 2024
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
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
One promethium isotope, with eighty-eight neutrons, has a half-life of a few days; the other, with eighty-six neutrons, has a half-life of a few years.
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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
