Bismuth Subnitrate: Bismuth through Nitrate and Carbonate to the White Powder (USP 1870)

The US Pharmacopoeia's 1870 bismuth subnitrate. Bismuth is dissolved in nitric acid, thrown down as carbonate with soda (which leaves arsenic behind in the solution), redissolved in nitric acid, and finally precipitated as the white subnitrate with water of ammonia. Source: The Dispensatory of the United States of America (1907), Bismuthi Subnitras, quoting the USP 1870. Nitric acid is a strong acid and gives off red fumes: fume hood. Picture drawn by Youblob.