Bi2S3 + 3(NH4)2CO3 + 2H2O → Bi2(OH)4CO3 + 6NH3 + 2CO2 + 3H2S
Bismuth(III) sulfide react with ammonium carbonate and water to produce bismuth(III) tetrahydroxide-dicarbonate, ammonia, carbon dioxide and hydrogen sulfide. The reaction takes place in a boiling solution.