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copernicium

(Encyclopedia)copernicium, artificially produced radioactive chemical element; symbol Cn; at. no. 112; mass number of most stable isotope 285; m.p., b.p., sp. gr., and valence unknown. Situated in Group 12 of the p...

Amherst, Jeffery Amherst, Baron

(Encyclopedia)Amherst, Jeffery Amherst, Baron ămˈərst [key], 1717–97, British army officer. He served in the War of the Austrian Succession and in the early part of the Seven Years War. In 1758 he was sent to ...

antioxidant

(Encyclopedia)antioxidant, substance that prevents or slows the breakdown of another substance by oxygen. Synthetic and natural antioxidants are used to slow the deterioration of gasoline and rubber, and such antio...

glycol

(Encyclopedia)glycol glīˈkōl [key], dihydric alcohol in which the two hydroxyl groups are bonded to different carbon atoms; the general formula for a glycol is (CH2)n(OH)2. The most important glycol is the simpl...

Guerrero

(Encyclopedia)Guerrero, state, 24,887 sq mi (64,457 sq km), S Mexico, on the Pacific Ocean. The capital is Chilpancingo. Dominated by the Sierra Madre del Sur, which ...

Motlanthe, Kgalema Petrus

(Encyclopedia)Motlanthe, Kgalema Petrus kälāˈmä, mōtlänˈtā [key], 1949–, South African politician, b. Johannesburg. A fierce opponent of apartheid, he was influenced by Steve Biko and organized student pr...

National Radio Astronomy Observatory

(Encyclopedia)National Radio Astronomy Observatory (NRAO), federal observatory for radio astronomy, founded in 1956 and operated under contract with the National Science Foundation by Associated Universities, Inc.,...

niobium

(Encyclopedia)niobium nīōˈbēəm [key], metallic chemical element; symbol Nb; at. no. 41; at. wt. 92.90638; m.p. about 2,468℃; b.p. 4,742℃; sp. gr. 8.57 at 20℃; valence +2, +3, +4, or +5. Niobium is a rare...

Ollivier, Émile

(Encyclopedia)Ollivier, Émile āmēlˈ ôlēvyāˈ [key], 1825–1913, French statesman, a leading figure in the “Liberal Empire” of Napoleon III. Widely known as a brilliant lawyer, he was elected to the legi...