| 释义 |
xanthic, a.|ˈzænθɪk|
[ad. F. xanthique, f. Gr. ξανθός yellow: see -ic.]
1. Chem. Epithet of certain compounds which produce substances of a yellow colour, or of bodies connected with these.
a. xanthic oxide, the original name of xanthine; so xanthic calculus, a urinary calculus containing xanthine.
1817Marcet Ess. Chem. Hist. Calculous Disorders iv. 99 If the potash be added to the pure xanthic substance,..no change of colour takes place. The residue of the solution of xanthic oxyd in water produces the yellow substance, when treated with nitric acid. Ibid. 101 Xanthic oxyd. Ibid. 102 In burning, it emitted an animal smell, which did not at all resemble that of the lithic, cystic, or xanthic calculus. 1857Miller Elem. Chem., Org. 642 Xanthic or Uric Oxide (C10H4N4O4) was discovered by Dr. Marcet as the principal constituent of a very rare variety of urinary calculus. 1872T. Bryant Pract. Surg. (1879) II. 84 Calculi of uric acid and the urates, with their modifications the oxalates, xanthic and cystic oxide.
b. xanthic acid, a complex acid containing sulphur and carbon, also called sulphocarbethylic or ethyldisulphocarbonic acid (C3H6OS2), many of whose salts (xanthates) are yellow. Hence more widely, any acid of the general formula RO·CS·SH or RO·CS·SR′. So xanthic ether, etc.
1831T. Thomson Syst. Chem. (ed. 7) II. 176 Xanthic acid is characterized by precipitating the salts of copper yellow. Ibid., During the distillation of xanthate of potash, a substance comes over which Zeise has distinguished by the name of xanthic oil. 1857Miller Elem. Chem., Org. 146 Xanthic or Sulphocarbethylic Acid. 1868Watts Dict. Chem. V. 498 Ethyldisulphocarbonic or Xanthic Acid..is a colourless oil, heavier than water,..its taste is acid, astringent, and bitter. Ibid. 500 Ethylic Disulphocarbonate or Xanthate, Xanthic Ether, C5H10OS2..has a pale-yellow colour, a sweetish taste. 1945Jrnl. Chem. Soc. 666 To interpret results obtained in other aspects of the chemistry of xanthic acid derivatives.., we found it necessary..to systematise current knowledge concerning the isomeric compounds RO·CS·SR′, R′O·CS·SR, RS·CO·SR′, the first two being esters of xanthic acids and the last an ester of sym. dithiocarbonic acid. 1956Kirk & Othmer Encycl. Chem. Technol. XV. 150 The relatively unimportant xanthic acids are unstable, colorless or yellow oils, and have been known, on occasion, to decompose with explosive violence.
2. Bot. De Candolle's name for a series or class of colours in flowers, of which the type is yellow: opp. to cyanic.
1843Florist's Jrnl. (1846) IV. 34 A most uncommon combination of colours—cyanic and xanthic tints in one and the same flower. 1885G. L. Goodale Physiol. Bot. (1892) 454. |