Columbia Encyclopedia

Search results

500 results found

osmium

(Encyclopedia)osmium ŏzˈmēəm [key], metallic chemical element; symbol Os; at. no. 76; at. wt. 190.23; m.p. 3,045±30℃; b.p. 5,027±100℃; sp. gr. 22.57 at 20℃; valence usually +0 to +8. Osmium is a very ha...

Pius VI

(Encyclopedia)Pius VI, 1717–99, pope (1775–99), an Italian named G. Angelo Braschi, b. Cesena; successor of Clement XIV. He was created cardinal in 1774. Early in his reign he was faced with the attempts of Hol...

thulium

(Encyclopedia)thulium tho͞oˈlēəm [key] [from Thule, an ancient name for Scandinavia], metallic chemical element; symbol Tm; at. no. 69; at. wt. 168.93421; m.p. about 1,545℃; b.p. 1,947℃; sp. gr. 9.3; valenc...

terbium

(Encyclopedia)terbium tûrˈbēəm [key] [from Ytterby, a village in Sweden], metallic chemical element; symbol Tb; at. no. 65; at. wt. 158.92535; m.p. 1,356℃; b.p. 3,123℃; sp. gr. about 8.25; valence +3 or +4....

ytterbium

(Encyclopedia)ytterbium ĭtûrˈbēəm [key] [for Ytterby, a town in Sweden], metallic chemical element; symbol Yb; at. no. 70; at. wt. 173.054; m.p. 819℃; b.p. about 1,194℃; sp. gr. about 7.0; valence +2 or +3...

rhodium

(Encyclopedia)rhodium rōˈdēəm [key], metallic chemical element; symbol Rh; at. no. 45; at. wt. 102.90550; m.p. about 1,966℃; b.p. 3,727±100℃; sp. gr. 12.41 at 20℃; valence +2, +3, +4, +5, or +6. Rhodium ...

Ciechanover, Aaron

(Encyclopedia)Ciechanover, Aaron, 1947–, Israeli biochemist, M.D. Hebrew Univ.–Hadassah Medical School, Jerusalem, 1974; D.Sc. Technion (Israel Institute of Technology), Haifa, 1982. He has been on the faculty ...

Chalfie, Martin

(Encyclopedia)Chalfie, Martin, 1947–, American biologist, b. Chicago, Ph.D. Harvard, 1977. In 1982 Chalfie joined the faculty at Columbia, where he is now the William R. Kenan, Jr., Professor of Biological Scienc...

hydroxyl group

(Encyclopedia)hydroxyl group hīdrŏkˈsĭl [key], in chemistry, functional group that consists of an oxygen atom joined by a single bond to a hydrogen atom. An alcohol is formed when a hydroxyl group is joined by ...

Hershko, Avram

(Encyclopedia)Hershko, Avram, 1937–, Israeli biochemist, M.D. Hebrew Univ.–Hadassah Medical School, Jerusalem, 1965, Ph.D. 1969. Hershko has been a professor at the Rappaport Faculty of Medicine at the Technion...