Cobalt III Sulfate 12-Hydrate

James L. Booker M.S. thesis, Texas Technological College, Lubbock, Tex., 1965. 

CESIUM COBALT(III) SULFATE 12-HYDRATE (Cesium Cobalt(fll) Alum) 

The only known solid compounds containing the ion Co(H20)6 are the sulfate Co2(S04)3 18H20 and its alums. Although the first synthesizer of the sulfate reported he was able to store it in a stoppered tube for months without visible decomposition, later authors stated that this compound and the ammonium alum decompose at laboratory temperature within a few hours. By an improved drying procedure, the cesium alum is readily obtained in a form in which even the magnetic susceptibility (a very sensitive criterion for the presence of dipositive cobalt) shows that only very slow decomposition occurs. Use of this 

The preparation is electrolytic. The anode consists of a few inches of thin platinum rod, to one end of which a 1 X f in. piece of platinum foil is attached. This is surrounded by a hollow cylinder of platinum gauze of diameter 1 in. and length 1 in. The other end of the platinum rod is attached to an electric stirrer.  

The cathode is a rolled strip of copper gauze which fits snugly into a 3 X f in. test tube and rests on a glass-wool plug which covers a hole of about -in. diameter blown in the bottom of the test tube. During the preparation, the solution about half fills the tube, and the glass-wool plug protects the bulk of the oxidized solution from the cathode. 

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