Preparation of sodium pyroantimonate
Three and four-tenths grams of antimony trisulfide is prepared by passing hydrogen sulfide into a solution of 6.6g potassium antimonyl tartrate (4.5g of the trichloride or 2.9g of the trioxide may be used instead) in 2N hydrochloric acid until precipitation is complete. The moist precipitate thus obtained, after being suction filtered and pressed down well, is carefully separated from the adhering filter paper by peeling the latter away cleanly and then stirred with 20ml of a 35% solution of sodium hydroxide (1 part solid alkali to 2 parts of water) until only a very small yellow residue remains. Slight warming aids the dissolution of the antimony trisulfide. The clear liquid (decanted from any residue) is diluted with water to 150ml and heated to 70-80° C. This temperature range is maintained while 50ml of 6% hydrogen peroxide is slowly added to the well-stirred liquid from a dropping funnel. The pale yellow color of the reaction mixture disappears towards the end of the oxidation while the sparingly soluble antimonate crystallizes out continuously. The sodium sulfide formed in the reaction is oxidized to sodium sulfate. The solution and precipitate are allowed to cool spontaneously to room temperature and the supernatant liquid is decanted. The solid is brought on to the filter with about 50ml of an equivolume water-alcohol mixture, washed twice with 20ml portions of the same solvent, then with absolute alcohol and finally dried in air yielding 4g of sodium pyroantimonate.
Inorganic laboratory preparations, by G. G. Schlessinger, 64-65, 1962
UNII-G4CAU13PF8, G4CAU13PF8, Sodium antimonate monohydrate, Sodium pyroantimonate monohydrate [MI], 30718-75-3