Sulfoxylate, cobalt

Cobalt(II) sulfoxylate, CoS02 a H20, is the only known salt of the unstable sulfoxylic acid, H2SO2. Scholder and Denk prepared this compound by the reaction of cobalt (II) acetate with sodium dithionite in the presence of a weak base. The following procedure is based on their method. 

To determine cobalt, it is merely necessary to ignite the compound in an electric furnace to about 825° for one hour and weigh the residue as C03O4. To analyze for sulfur, 0.3 to 0.4 g. of the compound is placed in 200 ml. of distilled water, and a few drops of bromine are added. When all the cobalt (II) sulfoxylate has reacted, the excess bromine is boiled off and the sulfur is precipitated as barium sulfate. Anal Calcd. for CoS02-2H20 Co, 37.07 S, 20.13. Found Co, 36.93 S, 19.62. By checkers Co, 36.7 S, 19.3. The Co S ratio here is 1.00 0.98. Because of the variability of the water content, the Co S ratio is more useful than either analysis alone. 

Cobalt (II) sulfoxylate is a brown powdery hygroscopic solid, which is obtained with varying water of hydration. It decomposes when attempts are made to convert it into the sulfoxylates of other metals. It is easily oxidized by agents such as nitric acid, bromine, or chlorine or when heated in the presence of air. It is insoluble in water and all common organic solvents. 

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