Preparation of barium trithiocarbonate
16 g of barium hydroxide octahydrate are dissolved in 50 ml of hot water and saturated with hydrogen sulfide. The pH of the resulting solution should be about 8 and the odor of the gas should persist even after it is well shaken. A clear solution of 16 g more of barium hydroxide solution is mixed with the first and cooled to give normal barium sulfide. Eight grams of carbon disulfide are added, the flask is stoppered, and then shaken for at least one-half hour. The yellow product is filtered by suction and washed, first with a 50% solution and then with 95% alcohol. The alcoholic washings precipitate more product from the filtrate. The material is dried in warm air. The yield of barium trithiocarbonate is 12-15 g. Acid decomposes the thiocarbonate to give unstable oily trithiocarbonic acid which dissociates into carbon disulfide and hydrogen sulfide.
Inorganic laboratory preparations, by G. G. Schlessinger, 40, 1962