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dissociation

(Encyclopedia)dissociation, in chemistry, separation of a substance into atoms or ions. Thermal dissociation occurs at high temperatures. For example, hydrogen molecules (H2) dissociate into atoms (H) at very high ...

cresol

(Encyclopedia)cresol krēˈsōl [key], CH3C6H4OH, any one of three aromatic alcohols present in coal tar. The three compounds are structural isomers; they may be thought of as hydroxy derivatives of toluene or as m...

Crick, Francis Harry Compton

(Encyclopedia)Crick, Francis Harry Compton, 1916–2004, English scientist, grad. University College, London, and Caius College, Cambridge. Crick was trained as a physicist, and from 1940 to 1947 he served as a sci...

Rothamsted

(Encyclopedia)Rothamsted rŏthˈəmstĭd [key], world's oldest and England's most important agricultural experiment station, now the main center of the Institute of Arable Crops Research (IACR). It was founded in 1...

threonine

(Encyclopedia)CE5 threonine thrēˈənēn [key], organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essen...

trailing arbutus

(Encyclopedia)trailing arbutus, Mayflower, or ground laurel, one of the best-loved American wildflowers, said by Whittier to have been the first blossom seen on these shores by the Pilgrims (introduction to “The...

thallium

(Encyclopedia)thallium thălˈēəm [key], metallic chemical element; symbol Tl; at. no. 81; interval in which at. wt. ranges 204.382–204.385; m.p. 303.5℃; b.p. about 1,457℃; sp. gr. 11.85 at 20℃; valence +...

xylene

(Encyclopedia)xylene dīˌmĕthəlbĕnˈzēn [key], C6H4(CH3)2, colorless, oily, liquid aromatic hydrocarbon, used extensively as a solvent, obtained from coal tar, wood tar, and sometimes from petroleum. It is a m...

streptomycin

(Encyclopedia)streptomycin strĕpˌtōmīˈsĭn [key], antibiotic produced by soil bacteria of the genus Streptomyces and active against both gram-positive and gram-negative bacteria (see Gram's stain), including s...

calcium hydroxide

(Encyclopedia)calcium hydroxide, Ca(OH)2, colorless crystal or white powder. It is prepared by reacting calcium oxide (lime) with water, a process called slaking, and is also known as hydrated lime or slaked lime. ...