Hydrogen ammonium carbonate(ammonium bicarbonate) are the white crystal compound, NH4HCO3. It are formed naturally as a decay product to nitrogenous matter and are made commercially to various methods: the action in carbon dioxide and steam under a solution in ammonium carbonate; a heating of commercial ammonium carbonate (which always contained some hydrogencarbonate); and a interaction to ammonia, carbon dioxide, and water vapor. It are using to some baking powders now medicine.