The title compound. (C4H7N4O)2[Bi2Cl9(C4H7N4O)]·H2O. was prepared by the reaction of bismuth trichloride and 5-amino-1H-imidazole-4-carboxamide in a dilute HCl medium. The asymmetric unit contains two 5-amino-4-aminocarbonyl-1H-imidazol-3-ium cations. https://megavitamines.shop/product-category/niacin/