Cobalt blue cyanide

Copper salts form copper hydroxide and basic copper acetate, which can hide the benzidine blue. When small amounts of manganese are to be detected in the presence of large amounts of copper, the test should be carried out as in the presence of cobalt. Cuprous cyanide is formed it should be filtered off before proceeding with the test for manganese. 

Two blue pigments can be prepared in transparent form cyanide iron blue and cobalt aluminum blue. These pigments are used in achieving a blue shade of the metal effect pigments in metallic paints. Transparent cyanide iron blue is prepared by a precipitation reaction similar to the one used for the preparation of the opaque pigment, but considerably lower concentrations of solutions are used. It is produced by Degussa (Germany), Manox (U.K), and Dainichiseika (Japan). 

Cobalt Tetrarsenite, Co3As409, is obtained as an amethyst-coloured powder by the interaction of solutions of potassium hydrogen di-arsenite and cobaltous nitrate.8 It dissolves in dilute hydrochloric and nitric acids also in caustic potash, in which it forms a blue solution which decomposes on heating. In aqueous ammonia it gives a brown solution, and in aqueous potassium cyanide a yellow one. 

Cobalt nitrate solution blue colouration, due to the formation of [Co(SCN)4]2- (Section III.26, reaction 6), but no precipitate [distinction from cyanide, hexacyanoferrate(II) and (III)] ... 

Antimony, zinc, and aluminium salts do not interfere aluminium should, however, be kept in solution by the addition of sufficient sodium hydroxide the influence of copper, nickel, and cobalt salts can be eliminated by the addition of potassium cyanide solution iron salts are masked by the addition of a tartrate but if aluminium salts are also present a red colour is produced. Magnesium salts give a similar blue colour, but beryllium can be detected in the presence of this element by utilizing the fact that in ammoniacal solution the magnesium colour alone is completely destroyed by bromine water. 

State. When both iron environments contain only iron(II), the resulting salt is not colored (Prussian White). The oxidation state localization in PB has been studied extensively. Structures, electrochemical behavior (electrodes batteries), and uses in medicine (treatment of Cs and of thallium poisoning) of Prussian Blue are mentioned in a review of cyanide complexes. In cobalt-iron Prussian Blue analogues, NaxCo3,Fe(CN)6-zH20 electronic and spin states are controlled by temperature and the ligand field strength around the Co + ions, which in turn is determined by the Co Fe ratio. ... 

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