Potassium cobalticyanide

Potassium cobalticyanide [13963-58-1 ] M 332.4. Crystd from water to remove traces of HCN. 

Potassium hexacyanocobaltate(HI) reagent (4%). Dissolve 4g potassium hexacyanocobaltate(III) (potassium cobalticyanide) K3[Co(CN)6] and 1 g potassium chlorate, KC103, in water and dilute to 100 ml. 

Properties of cobalt. Ores—smaltite, cobaltite. Alnico and other alloys, Cobaltous chloride, cobaltous oxide, cobaltic hydroxide, potassium cobaltinitrite, potassium cobalticyanide. Cobalt glass. 

Within the category of ionic crystals, there are two similar complex ions of cobalt (III) which have been extensively studied cobaltic trisethylenediamine nitrate (9 ) and potassium cobalticyanide (6S). Both these crystals show fairly low inherent retentions (approximately 5% and 19%, respectively) and both give evidence of fragments having... 

James and Monk (loc. dt.) also measured the conductance of potassium cobalticyanide and an extrapolation by the method used in problem 95 gives for the equivalent conductance at infinite dilution... 

Potassium cobalticyanide Potassium cobalticyanine. See Cobalt potassium cyanide... 

This test is affected by large amounts of ammonium salts they should be removed beforehand. Aluminum, in not too great excess, lead, zinc, and antimony salts do not interfere. Solutions of copper and nickel salts can be decolorized by adding potassium cyanide, whereas cobalt salts form the Light yellow soluble potassium cobalticyanide K3[Co(CN) ], which does not interfere with the recognition of the blue of the quinalizarin compound. Iron salts may be masked by means of tartrates. However, tartrates interfere if aluminum is present because a red color is formed in the caustic alkaline solution of quinalizarin. If both iron and aluminum are present, the test solution should be treated with 5 ml of 1 iV NaOH, cooled, diluted to 15 ml, and then filtered if necessary. The dear solution contains any beryllium as beryllate and can be tested as described below. 

According to some authorities, the first metal ammine to be isolated in the solid state was the reddish yellow hexaamminecobalt(III) oxalate [Co(NH3)6]2(C204)3, described in 1822 by Leopold Gmelin (1788-1853).16 Gmelin also discovered several new double salts potassium ferricyanide, or potassium hexacyanoferrate(III), K3[Fe(CN)6l>17 the cobalticyanides or hexacyanocobaltates(III), M3[Co(CN) ],18 and the platinocyanides or tetracyanoplatinates(II), M2[Pt(CN)4].19All these substances certainly deserve to rank among the earliest known coordination compounds. 

Place a few drops of the neutral (litmus) test solution upon potassium hexa-cyanocobaltate(III) (or cobalticyanide, Rinmann s green) test paper. Dry the paper over a flame and ignite in a small crucible. Observe the colour of the ash against a white background part of it will be green. 

The potassium hexacyanocobaltate(III) (or cobalticyanide) test paper is prepared by soaking drop-reaction paper or quantitative filter paper in a solution containing 4 g potassium hexacyanocobaltate(III) and 1 g potassium chlorate in 100 ml water, and drying at room temperature or at 100°C. The paper is yellow and keeps well. 

Zinc cobalticyanide can be obtained as an amorphous precipitate (114) from zinc chloride and potassium or calcium cobalticyanide in water. The product has a formula... 

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