- erbium by Melanie Berry
metallic chemical element; symbol Er; at. No. 68; at. Wt. 167.26; m.p. 1,529°C; b.p. 2,863°C; sp. Gr. 9.05 at 25°C; valence +3. Erbium is a soft, malleable, lustrous, silvery metal. It is a member of the lanthanide series in Group 3 of the periodic table. With other rare earths its oxide occurs in the mineral gadolinite, found in Sweden. Natural erbium is a mixture of 6 stable isotopes ...
- Peroxide by Webster's
... n.) An oxide containing more oxygen than some other oxide of the same element. Formerly peroxides were regarded as the highest oxides. Cf. Per-, 2.
- atomic number 68 by WordNet
nounA trivalent metallic element of the rare earth group; occurs with yttrium.synonyms: erbium, Er
- rare earth metal by Dawson Fletcher
Any of a large class of chemical elements including scandium (atomic number 21), yttrium (39), and the 15 elements from 57 (lanthanum) to 71 ( see lanthanides). The rare earths themselves are pure or mixed oxides of these metals, originally thought to be quite scarce; however, cerium, the most plentiful, is three times as abundant as lead in the Earth's crust. The metals never occur free, and ...
- Marignac, Jean Charles Galissard de by Great Soviet Encyclopedia
Born Apr. 24, 1817, in Geneva; died there Apr. 16, 1894. Swiss chemist. Member of the Paris Academy of Sciences (1886).Marignac graduated from the School of Mines in Paris in 1839. He held a professorship at the University of Geneva from 1841 to 1878. Between 1842 and 1883, Marignac determined the atomic weights of 29 elements, thereby verifying Prout’s hypothesis. In 1866 he developed a method ...