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promethium
(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...Periodic Table of the Elements: Promethium
(Encyclopedia)Periodic Table of the Elements: Promethium ...florentium
(Encyclopedia)florentium: see promethium.Pm
(Encyclopedia)Pm, symbol for the element promethium. ...illinium
(Encyclopedia)illinium ĭlĭnˈēəm [key]: see promethium. ...rare-earth metals
(Encyclopedia)rare-earth metals, in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, whi...lanthanide series
(Encyclopedia)lanthanide series, a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic nu...synthetic elements
(Encyclopedia)synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element...Elements (table)
(Encyclopedia)Elements 1 Parentheses indicate most stable isotope; brackets enclose lower and upper bounds of weight variation. ...Browse by Subject
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