Potassium Hexacyanodinickelate I

Nickel powder is light gray in color and may be pyrophoric in air if the particle size is sufficiently small. Nickel powder is useful as a catalyst for many organic chemical reactions or as a starting material for the synthesis of nickel compounds. 

Submitted by Wayland M. Burgess t and John W. EastesI Checked by William E. Parker J and Jacob Klein berg J 

Reduction of aqueous solutions of potassium tetra-cyanonickelate(II), e.g., by hydroxylamine, potassium amalgam, or tin and sodium hydroxide, yields a red solu- 

The following directions describe the preparation of the nickel(I) compound in liquid ammonia solution.2 

An apparatus is constructed as indicated in Fig. 17. Individual sections of the apparatus are connected by 

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Potassium hexacyanodinickelate-(I), synthesis 57 Ammonium hexabromoosmate-(IV), synthesis 59 Ammonium hexachloroosmate-(IV), synthesis 60... 

Potassium hexacyanodinickelate(I) is a bright red compound which reacts slowly in air to form a yellow solid. It is insoluble in ethanol and liquid ammonia but dissolves readily in water, giving a blood-red solution with strong reducing properties. In the presence of excess cyanide ion the unipositive nickel is rapidly oxidized by water to the dipositive condition. It has been reported1 that acidification of aqueous solutions of the complex results in the precipitation of nickel(I) cyanide and that the latter dissolves in aqueous potassium cyanide with the formation of the original complex. Solutions of the unipositive nickel complex rapidly absorb carbon monoxide... 

Nickel powder, synthesis 56 Potassium hexacyanodinickel-ate(I), synthesis 57 Sodium and potassium nickel(IV) paraperiodates, synthesis 58... 

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