| 释义 |
divalent, a. Chem.|ˈdaɪvələnt, ˈdɪv-|
[f. di-2 twice + L. valēnt-em, pr. pple. of valēre to be worth.]
Combining with two atoms of hydrogen or other univalent element or radical; having two combining equivalents; also bivalent.
A diatomic element, e.g. oxygen, is divalent; so is the highly complex molecule C5H10 = (CH3)2·C·(CH2)2, which has two combining powers unsaturated.
1869Roscoe Elem. Chem. 183 Calcium, Strontium, Barium. The metals of this class are divalent. 1870F. Hurter in Eng. Mech. 11 Feb. 524/2 Oxygen is called divalent, or bivalent, because it can hold two atoms of a monogenous element. 1881Academy 15 Jan. 47/1 In like manner the term ‘divalent’ may be given to such atoms as are equal in combining power to two atoms of hydrogen.
Add: Hence diˈvalence n., diˈvalency n. = bivalency n.
1888Bedson & Williams tr. Meyer's Mod. Theories Chem. ix. 333 On account of the divalency of oxygen..they [sc. compounds with oxygen] would at first sight appear to afford but an unsuitable and doubtful means of determining the valency. 1909Cent. Dict. Suppl., Divalence. 1927N. V. Sidgwick Electronic Theory of Valency 270 These two effects can lead ultimately to the divalency of the elements of both subgroups. 1972Physical Rev. B V. 2738 The divalence of both Cd and Hg in trivalent In suggests that solute electropositivity is a possible origin of the anomaly. 1979Nature 13 Dec. 743/2 A new ultrastructural post-embedding staining technique, based on the divalency of IgG molecules. 1985Jrnl. Magnetism XLVII–XLVIII. 594/1 Eu ions in the high temperature regions assume integral divalence in cerium. |