Columbia Encyclopedia

Search results

500 results found

neptunium

(Encyclopedia)neptunium nĕpto͞oˈnēəm [key], radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640℃; b.p. 3,902℃ (estimated); sp. gr. 20.25 at 20℃; va...

tantalum

(Encyclopedia)tantalum tănˈtələm [key] [from Tantalus], metallic chemical element; symbol Ta; at. no. 73; at. wt. 180.94788; m.p. 2,996℃; b.p. 5,400±100℃; sp. gr. 16.65 at 20℃; valence +2, +3, +4, or +5....

cadmium

(Encyclopedia)cadmium kădˈmēəm [key] [from cadmia, Lat. for calamine, with which cadmium is found associated], metallic chemical element; symbol Cd; at. no. 48; at. wt. 112.411; m.p. 321℃; b.p. 765℃; sp. gr...

bismuth

(Encyclopedia)bismuth bĭzˈməth [key] [Ger. Weisse Masse=white mass], metallic chemical element; symbol Bi; at. no. 83; at. wt. 208.98040; m.p. 271.3℃; b.p. about 1,560℃; sp. gr. 9.75 at 20℃; valence +3 or ...

Guillemin, Roger Charles Louis

(Encyclopedia)Guillemin, Roger Charles Louis gēyəmăNˈ [key], 1924–, French-American physiologist, b. Dijon, France. Educated in France, he fought for the resistance during World War II. He taught primarily at...

Gibbs, Josiah Willard

(Encyclopedia)Gibbs, Josiah Willard, 1839–1903, American mathematical physicist, b. New Haven, Conn., grad. Yale, 1858. He studied abroad and was professor of mathematical physics at Yale from 1871. His great con...

Grubbs, Robert Howard

(Encyclopedia)Grubbs, Robert Howard, 1942–2021, American chemist, b. near Possum Trot, Ky., Univ. of Florida (B.S., 1963; M.S., 1965), Columbia, Univ. (Ph.D, 1968)....

Friedrich Schiller University of Jena

(Encyclopedia)Friedrich Schiller University of Jena frēˈdrĭkh shĭlˈər, yāˈnə [key], at Jena, Germany; founded 1548 as an academy; became the Univ. of Jena 10 years later. The school gained an international...

ammonium group

(Encyclopedia)ammonium group, in chemistry, a positively charged nitrogen atom joined by single bonds to four other atoms or groups. The simplest ammonium group, NH4+, is formed by protonation of ammonia, NH3, e.g....

Frank, Joachim

(Encyclopedia)Frank, Joachim, 1940–, German-American physicist and biochemist, b. Siegen, Germany, Ph.D., Technical Univ. of Munich 1970. He became a U.S. citizen in 1997. Following several postdoctoral appointme...