cation Electr.
(ˈkætaɪən, formerly ˈkætɪən)
[a. Gr. κατιόν (a thing) going down, neut. of pr. pple. of κατ-ιέναι to go down, f. κατά down + ἰ- go.]
a. An ion carrying a positive charge which moves towards the cathode (negative electrode) during electrolysis. Opp. anion.
| 1834 Faraday Res. Electr. (1839) §655, I require a term to express those bodies which can pass to the electrodes, or, as they are usually called, the poles..I propose to distinguish such bodies by calling those anions which go to the anode of the decomposing body; and those passing to the cathode, cations. 1839 Grove in Corr. Phys. Forces 238 The cations of the electrolytes. 1885 Watson & Burbury Math. Th. Elect. & Magnt. I. 231. |
b. cation exchange, ion exchange involving cations; also
attrib.; so
cation exchanger, a substance capable of cation exchange.
cation-active a., having an active cation.
| 1834, 1931 [see anion]. 1946 Nature 26 Oct. 585/2 The addition of divalent metallic ions greatly enhances the surface-active properties of anion-active detergents, and it was suggested..that a similar effect should occur on adding divalent anions to cation-active substances. |
| 1931 Soil Science XXXI. 320 If the cation exchange capacity depends upon the number of free silicate or other acidoid valences, [etc.]. 1950 Amer. Jrnl. Med. Sci. CCXX. 547 (title) Treatment of Potassium Retention in Anuria with Cation Exchange Resins. 1957 Encycl. Brit. XII. 573/2 In water softening..calcium and magnesium ions..are removed by a granular bed of cation exchanger and replaced by sodium ions from the cation exchanger. 1963 [see anion]. |