| 释义 |
parachor Chem.|ˈpærəkɔː(r)|
[f. para-1 + Gr. χορός (= dance, but taken by the coiner, in mistake for χώρα, as = space).]
A numerical quantity (found empirically to be constant over a wide range of temperature) equal to the molecular weight of a liquid multiplied by the fourth root of its surface tension and divided by the difference between its density and that of its vapour.
1924S. Sugden in Jrnl. Chem. Soc. CXXV. i. 1178 The quantity P can be regarded as function of chemical composition. For saturated substances, P is an additive function... It is proposed to name this quantity the parachor..to signify comparative volume. 1940Glasstone Textbk. Physical Chem. viii. 517 The mean parachor equivalent of the —NC group, in a number of alkyl and aryl isocyanides, is 66; this corresponds closely to that required for the structure —N+≡C-, thus N(12·5), C(4·8), triple bond (46·6), making a total of 63·9. The alternative structure —N{b2}C would have a parachor equivalent of only 40·6. 1956I. L. Finar Org. Chem. II. i. 9 A comparison of parachors of different liquids gives a comparison of molecular volumes at temperatures at which liquids have the same surface tension. 1974Nature 22 Nov. 296/2 For a given salt, ks was proportional to the characteristic volume of the non-electrolyte which in m3 mol-1 equals the parachor (calculated in the usual way in c.g.s units) × 10-6. |