Synonym. Ammonias Sesquicarbonas. Lond. Dub.

Prep. By heating a mixture of hydrochlorate of ammonia and chalk, when chloride of calcium, and carbonate of ammonia, are formed, the latter rises in vapour and is condensed. The exact changes are not, however, quite so simple, for a neutral carbonate of ammonium is not the result, as will be seen below. It is sometimes made from sulphate of ammonia and chalk; the sulphate being formed by the addition of gypsum or sulphuric acid to gas liquors or bone spirit.

Prop. & Comp. Colourless, almost transparent, crystalline masses, with powerful ammoniacal odour and acrid taste; strongly alkaline, volatilizes with heat, soluble in water, more sparingly in spirit; and readily dissolved by acids with effervescence. Its composition is represented by the formula, 2 Nh4 O, 3 Co2. Exposed to air the odour is dissipated from the continued volatilization of the neutral carbonate at the ordinary temperature, and a white opaque salt remains: 2 H4 NO, 3 Co2 being resolved into

[Nh4 O, Co2 + HO, Co2] + Nh3, Co2, or a compound of bicarbonate of oxide of ammonium, the odourless, less soluble and less volatile salt, and a pungent compound of ammonia and carbonic acid, which can scarcely be looked upon as a true salt of ammonia: the solution, when saturated with nitric acid, is not precipitated by chloride of barium or nitrate of silver, showing the absence of sulphates and chlorides. Fifty grains are exactly neutralized by 84.74 measures of the volumetric solution of oxalic acid. This salt should be kept in a crystallized state, not in powder.

Off. Prep. Spiritus Ammoniae Aromaticus. Aromatic Spirit of Ammonia. (Carbonate of ammonia, eight ounces; strong solution of ammonia, four fluid ounces; volatile oil of nutmeg, four fluid drachms; oil of lemon, six fluid drachms; rectified spirit, one hundred and twenty fluid ounces; water, sixty fluid ounces: mix and distil one hundred and forty ounces.) [Spiritus Ammonia!. Spirit of Ammonia. Take of muriate of ammonia, in small pieces, lime, each twelve troy ounces; water, six pints; alcohol, twenty fluid ounces. Pour a pint of water on the lime, and stir to the consistence of a smooth paste. Add the remainder of the water, and mix well. Decant the milky liquid from the sediment, into a glass retort, of the capacity of sixteen pints, and add the muriate of ammonia. Place the retort on a sand bath, and adapt it to a receiver, previously connected with a two-pint bottle containing the alcohol, by means of a glass tube reaching nearly to the bottom of the bottle. Surround the bottle with ice-cold water; and apply a gradually increasing heat until ammonia ceases to be given off. Lastly, remove the liquid from the bottle, and introduce it into small bottles, which must be well stopped. U. S.] [Spiritus Ammonias Aromaticus. Carbonate of ammonia, a troy ounce; water of ammonia, three fluid ounces; oil of lemon, two fluid drachms and a half; oil of nutmeg, forty minims; oil of lavender, fifteen minims; alcohol, a pint and a half; water, a sufficient quantity. Dissolve the carbonate in the water of ammonia, previously mixed with four fluid ounces of water. Dissolve the oils in the alcohol, mix, and add sufficient water to make the whole measure two pints. U. S.] The proportions of am monia and carbonic acid in this preparation are such as to insure the formation of a neutral carbonate of ammonia. Its specific gravity is 0.870. Often called Sal Volatile.

Therapeutics. Carbonate or sesquicarbonate of ammonia, when fresh, acts both internally and externally in the same manner as free ammonia (vide Liq. ammoniae); occasionally, but very seldom, it is used as an emetic; when old, or after exposure, it acts much less powerfully as an excitant, but resembles the other ammoniacal salts (vide Ammoniae bicarbonas).

Dose. Of the salt, as a stimulant, 3 gr. to 10 gr. or more. As an emetic, 30 gr. may be given well diluted; occasionally useful as an emetic in asthenic bronchitis with deficient expectoration. Of aromatic spirits of ammonia, 20 min. to 1 fl. dr.

Adulteration. The salt may be deficient in volatile carbonate of ammonia on account of previous exposure; sulphates or chlorides may be present; these are detected by the tests given above.