Preparation of cobalt tetrakis(thiocyanato)mercurate
Thirty grams of mercuric chloride and 44.5g of potassium thiocyanate are dissolved in 500ml of water and mixed with a solution of 20g of cobalt nitrate 6-hydrate in 50ml of water. A shower of small deep blue crystals of the difficultly soluble complex salt begins to form almost immediately. The mixture is allowed to stand for twelve hours to complete the precipitation and then suction-filtered. The product is washed with three 30ml portions of cold water, drained well, and then rinsed with two 25ml volumes of 95% alcohol to aid in drying. The material is dried in air or in the oven at 100°C. Yield 34g.
Inorganic laboratory preparations, by G. G. Schlessinger, 81, 1962