cationn.

1834 M. Faraday Exper. 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 W. R. Grove in London & Edinb. Philos. Mag. Aug. 82 The cations of the electrolyte.

1885 H. W. Watson & S. H. Burbury Math. Theory Electr. & Magn. I. 231.

1931 Soil Science XXXI. 320 If the cation exchange capacity depends upon the number of free silicate or other acidoid valences, [etc.].

1931 S. Mattson in Soil Science XXXI. 325 Cation exchange predominates at high pH values whereas anion exchange predominates at low pH values.

1950 Amer. Jrnl. Med. Sci. 220 547 (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.

1834 W. Whewell Let. 5 May in I. Todhunter William Whewell (1876) II. 182 If you take anode and cathode, I would propose for the two elements resulting from electrolysis the terms anion and cation,..and for the two together you might use the term ions.

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.

1963 A. J. Hall Student's Handbk. Textile Sci. vi. 296 Surface active agents or surfactants can be usefully classified into three main groups—anion-active, non-ionic, and cation-active.