| 释义 |
locant Chem.|ˈlɒkənt|
[f. L. locant-, locans, pres. pple. of locāre (see locate v.).]
A number or letter in the name or cipher of a compound that indicates the position in its molecular structure of a constituent atom or group.
1946G. M. Dyson in R. Inst. Chem. Lect. New Notation Org. Chem. 10 A number immediately preceding a symbol is referred to as a locant, as, for example, in ‘2ZN’ or ‘6, 7QC’; in the second example both 6 and 7 are locants. 1952Chem. & Engin. News 2 June 2337/1 He [sc. G. M. Dyson] also thinks that a subscript might be used to indicate a number of identical locants; for example 1,1,1,2,2,3,3,4-octachloro- might be written 13,22,32,4-octachloro-. 1965Nomencl. Org. Chem. (I.U.P.A.C.) C. 29 The starting point and direction of numbering of a compound are chosen so as to give lowest locants to the following structural factors (if present). 1968R. S. Cahn Introd. Chem. Nomencl. (ed. 3) viii. 79 Locants used for the ring system are the usual numerals—the ‘2’ in the examples above refer to the 2-position of the naphthalene nucleus. |