Cobalt Chromate

Cobaltous chromate (CoCrO ) is brownish-yellow to grayish-black (the color depends on its purity) is a dangerous carcinogen (causes cancer). 

Cobalt Chromate. See under Chromates in this Vol, p CZ79-R... 

Neutral solutions of cobalt salts produce with potassium chromate a reddish brown precipitate of hydrated basic cobalt chromate, Co0.CoGrO4.Aq. This reaction may be utilised in detecting small quantities of cobalt.4... 

Cobalt Chromate, CoCr04, is prepared by heating cobalt carbonate and chromic acid solution for several hours at 185° C. in a sealed tube.5 It yields greyish black crystals, readily soluble in hot dilute nitric acid (contrast nickel chromate). The dihydrate, CoCr04.2H20, is obtained by the interaction of cobaltic acetate and potassium chromate. It yields bronze-coloured prisms or leaflets.5... 

Double Chromates.—Several double chromates containing cobalt have been prepared. Ammonium cobalt chromate, (NH4)2Cr04. CoCr04.6H20, is obtained by interaction of ammonium chromate and cobalt acetate in aqueous solution at low temperatures,6 and the corresponding caesium, cobalt chromate is known.6 Other complex derivatives have been described.7... 

Properties Brown or yellowish-brown powder. Variable composition. (Pure cobaltous chromate is CoCr04, gray-black crystals.) Soluble in mineral acids and solutions of chromium trioxide insoluble in water. 

Basic chromic sulfate Basic chromium sulfate. See Chromium sulfate, basic Basic cobalt chromate. See Cobalt chromate (ous)... 

Synonyms Basic cobalt chromate Chromic acid, cobalt (2+) salt (1 1) Cobalt chromate Cobalt (II) chromate Cobalt dichromIum tetraoxide... 

Cobalt Nitrate, Co(N03)2.6H20. Soluble cobalt compounds sometimes used in the ceramic industry for the purpose of neutralizing the slightly yellow colour caused by the presence of iron impurities the principle is the same as the use of a blue bag in the laundry. Cobalt Chromate, CoCr04. Finds some use, in admixture with ZnO and AI2O3, as a green or blue colour for vitreous enamels. 

The German author Jamiicke (1893) discusses blue oxide and green blue oxide Blauoxyd and Griinblauoxyd ). Blue oxide is described as a cobalt chromate green blue oxide is seemingly a mixture of cobalt and chromium oxides. 

Chromates with group 3-11 elements (Mn, Fe, Co, Cu, Ag, Th) cobalt chromate (CoCr204) copper chromate(lll) (CuCr204) copper chromate) VI) (CUC1O4) copper chromate hydroxide (CuCt04.Cu(0H)2 CuCr04.2Cu(0H)2 2CuCi04.3Cu... 

The German author Jannicke (1893) describes blue oxide as a cobalt chromate. Little is known about this compoimd as a pigment. It may have been confused with Turkish green q.v.), however a chromium cobalt oxide (CoCr204) is described as a green pigment in the Merck Index (1996). 

Cobalt group Chromium aluminium cobalt oxide Cobalt aluminium oxide Cobalt arsenate Cobalt arsenic oxide hydrate Cobalt chromate Cobalt hexacyanoferrate(II) Cobalt iron oxide Cobalt magnesium oxide Cobalt tin oxide Cobalt tungstate Cobalt zinc oxide Cobalt(III) oxide Erythrite Cobalt black Cobalt blue Cobalt violet... 

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