| 释义 |
valency|ˈveɪlənsɪ|
Also 7 -cie.
[ad. L. (ante- and post-classical) valentia vigour, capacity, f. valēre to be well or strong. Cf. Sp. and Pg. valentia, It. valenza, valenzia.]
†1. Might, power, strength. Obs.—0
1623in Cockeram 1. 1656 in Blount.
2. Chem.
a. The power or capacity of certain elements to combine with or displace a greater or less number of hydrogen (or other) atoms; atomicity.
Cf. equivalency 2 and valence2 3.
1869English Mechanic 19 Nov. 222/2 Any typical atom in any molecule may be replaced by another atom of similar valency, without altering the arrangement of the molecule. 1876Encycl. Brit. V. 473/2 The valency of an element is usually expressed by dashes or Roman numerals placed on the right of its symbol. a1881A. Barratt Phys. Metempiric 65, I think it will probably be eventually found that the atoms of high ‘atomicity’ or valency are really molecules. 1894Athenæum 14 Apr. 481/1 The valencies and atomic weights in some cases need correction.
b. A unit of this capacity. Usu. in pl.
1869English Mechanic 19 Nov. 222/1 The Molecule..is therefore a body in which all the attractions or valencies are satisfied, leaving the combined atoms to act as a whole from one centre. 1891Cent. Dict. s.v., Carbon is said to have four valencies.
3. Importance, significance.
1897Allbutt's Syst. Med. III. 166 These two conditions..are by no means of identical pathological valency.
4. attrib. and Comb., valency electron Physics = valence electron s.v. valence2 5.
1908Jrnl. Chem. Soc. XCIV. ii. 138 Two types of electrons are distinguished: the one type, arranged in the form of a ring, represents the positive electricity of the atom, and the second type consists of electrons which neutralise the positive charge of the ring and are separated from the atom when ionisation takes place, these being termed the valency electrons. 1973J. G. Tweeddale Materials Technol. I. iv. 97 Metals tend to be good conductors of heat primarily because there is sharing of valency electrons..and so electron transfer is easy. |