Preparation of potassium pentanitromercurate(II) monohydrate
Seventy-five grams of pure potassium nitrite are dissolved in 240g of 10% acetic acid, and 21.5g of yellow or red mercuric oxide are added. The mixture is agitated until all the oxide has dissolved; gentle heating aids in the solution of the last traces. The yellow liquid is evaporated on the steam bath to a volume of about 50ml and cooled in ice. The product is filtered off and washed with three 30ml portions of alcohol which are allowed to run into the mother liquor. A further crop of crystals can be isolated by working up the combined filtrate through evaporation. The residual liquid is thoroughly triturated with about 30ml of 95% alcohol to obtain more product; the potassium acetate is readily soluble in alcohol. Yields of 90% and over can easily be obtained.
Inorganic laboratory preparations, by G. G. Schlessinger, 94-95, 1962