=Ammonium, Bicarbonate of.= HNH_{4}CO_{3}. _Prep._ By digesting cold water on sesquicarbonate of ammonia in considerable excess, until the whole of the pungent neutral carbonate is dissolved out. If the salt is reduced to powder the operation is facilitated. To powdered sesquicarbonate of ammonia add boiling water just sufficient to dissolve it, and immediately close the vessel; crystals form as the liquid cools, containing 2-1/2 equiv. of water. _Prop., &c._ For the most part similar to the sesquicarbonate, except in having a taste and smell which is only faintly ammoniacal, and hence more palatable. Crystallises in oblique prisms, which, as usually obtained, contain about 23% of water. It requires 8 parts of cold water to dissolve it. It is distinguished from the previous carbonates by the almost entire absence of ammoniacal odour, and by its solution giving no immediate precipitate with chloride of barium, but by standing, or on the addition of a little liquor of ammonia, a white earthy precipitate, accompanied with the evolution of carbonic acid gas. A saturated solution of this salt, evaporated by a very gentle heat, or refrigerated, gives small prismatic crystals having neither smell nor taste. _Uses, &c._ Similar to those of the other carbonates.——_Dose_, 6 or 7 to 20 or 25 gr. =Ammonium, Chloride of.= NH_{4}Cl. _Syn._ MURIATE OF AMMONIA, SAL AMMONIAC, HYDROCHLORATE OF AMMONIA; CHLOROHYDRATE D’AMMONIAQUE, SEL AMMONIAC, &c., Fr.; SALMIAK, Ger. A substance which, as already noticed, appears to have been originally obtained, by sublimation, from the soot of camels’ dung, in Egypt. In this country, at the present day, it is manufactured chiefly from the crude ammoniacal liquors obtained as secondary products in the manufacture of coal-gas and animal charcoal.