Except the carbonate, they are almost invariably estimated by conversion into ammonia, and estimation by volumetric analyses, as in alkalimetry. In the laboratory, however, for exact purposes, they are converted into the double chloride of ammonium and platinum. =Ammonium Salts:——= =Ammonium, Acetate of.= NH_{4}C_{2}H_{3}O_{2}. _Syn._ AMMO′′NIÆ ACE′TAS, L.; ACETATE D’AMMONIAQUE, Fr.; ESSIGSÄURES AMMONIAK, Ger. _Prep._ 1. Take of acetate of lime or of potassa and sal ammoniac, equal parts; mix and distil at a gentle heat. The oily liquid (BINACETATE OF AMMONIUM, HNH_{4}(C_{2}H_{3}O_{2})_{2}), in the receiver forms a radiated crystalline mass on cooling. Dry gaseous ammonia passed into this salt, melted by a gentle heat, transforms it into the solid and inodorous neutral acetate, NH_{4}C_{2}H_{3}O_{2}. 2. Strong acetic acid is saturated with ammonia or carbonate of ammonium, and the solution evaporated over sulphuric acid in vacuo; the resulting crystals, after being carefully drained, are dried by pressure between bibulous paper. _Prop., &c._ Long, slender crystals, or a crystalline mass, freely soluble in both alcohol and water, and deliquescent in the air; taste sharp and cooling, and somewhat sweetish. Its solutions cannot be evaporated without loss of the ammonia; even the salt passes off in large quantities with the vapour of water. Its aqueous solution becomes alkaline on keeping, from decomposition of the acid. Distilled with anhydrous phosphoric acid, it is converted into ACETONITRILE. An aqueous solution of this salt was introduced into the Materia Medica by Boerhaave, and has since been extensively used as a diaphoretic and febrifuge, under the popular name of MINDERERUS SPIRIT, after Minderer or Mindererus, who extensively employed it and extolled its virtues. When pure, both the salt and its solutions are neutral to test-paper, and are wholly volatilised by heat. See SOLUTIONS. =Ammonium, Arseniate of.= (NH_{4})_{3}AsO_{4}. _Syn._ AMMONIÆ ARSE′NIAS, L. _Prep._ 1. (NEUTRAL.) Saturate a warm concentrated solution of arsenic acid with carbonate of ammonium in slight excess; evaporate by a gentle heat, that crystals may form on cooling. 2. =Ammonium, Binarseniate of.= H(NH_{4})_{2}AsO_{4}. As above, but adding an additional equiv. of the acid, as soon as any excess of ammonia has been expelled by the heat employed to evaporate the solution.——_Dose_ (of either). 1-24th to 1-12th gr.; in phthisis, certain skin diseases, &c. See SOLUTIONS (and _below_). =Ammonium, Arsenite of.= NH_{4}AsO_{2}. _Syn._ AMMONIÆ AR′SENIS, L. _Prep._ From a hot concentrated solution of arsenious acid, and sesquicarbonate of ammonium, as the last.——Used (chiefly) to make arsenite of iron. The properties and physiological effects of the above arsenical preparations are for the most part similar to those of arseniate and arsenate of potassa. They are all poisonous.