Definitions for promethiumprəˈmi θi əm
This page provides all possible meanings and translations of the word promethium
Random House Webster's College Dictionary
pro•me•thi•umprəˈmi θi əm(n.)
a rare-earth, metallic, trivalent element.
Ref: Symbol: Pm; 1
Origin of promethium:
1948; Promethe (us ) + -ium2
promethium, Pm, atomic number 61(noun)
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
a metallic chemical element (symbol Pm) with an atomic number of 61.
Origin: 1945. From the name of the Greek god Prometheus, who stole the fire from Mount Olympus and brought it down to mankind.
Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements. Promethium shows only one stable oxidation state of +3; however, a few +2 compounds may exist. In 1902, Bohuslav Brauner suggested there was an element with properties intermediate between those of the known elements neodymium and samarium; this was confirmed in 1914 by Henry Moseley who, having measured the atomic numbers of all the elements then known, found there was no element with atomic number 61. In 1926, an Italian and an American group claimed to have isolated a sample of element 61; both "discoveries" were soon proven to be false. In 1938, during a nuclear experiment conducted at Ohio State University, a few radioactive nuclides were produced that certainly were not radioisotopes of neodymium or samarium, but there was a lack of chemical proof that element 61 was produced, and the discovery was not generally recognized. Promethium was first produced and characterized at Oak Ridge National Laboratory in 1945 by the separation and analysis of the fission products of uranium fuel irradiated in a graphite reactor. The discoverers proposed the name "prometheum", derived from Prometheus, the Titan in Greek mythology who stole fire from Mount Olympus and brought it down to humans, to symbolize "both the daring and the possible misuse of mankind's intellect." However, a sample of the metal was made only in 1963.
U.S. National Library of Medicine
Promethium. A radioactive element of the rare earth family of metals. It has the atomic symbol Pm, atomic number 61, and atomic weight 147. It has been used in the construction of atomic batteries, in the preparation of self-luminous compounds, and as a beta-particle source for thickness gauges.
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