Ammonium, Iodide of

NH 4 I. Syn. Hydriodate of ammonia ; Ammo′′nii iodi′dum , L.; Hydriodate d’ammonia que , Fr. Prep. An aqueous solution of hydriodic acid is neutralised with ammonia, or ammonium sesquicarbonate, in slight exce ; and the resulting liquid is either carefully, but rapidly, evaporated to dryne over a water bath, or it is concentrated by the same means, and then caused to deposit crystals by refrigeration; in both cases care is taken to keep a slight exce of ammonia present during the evaporation. The crystals are dried by pre ure between folds of bibulous paper; and the product, in either form, preserved in a stoppered bottle. Pure iodine is triturated with a little distilled water, and solution of ammonium sulphydrate added, in small quantities at a time, with continued trituration, until the red colour of the iodine has entirely disappeared. The solution, after being gently boiled for a few seconds, to expel the sulphuretted hydrogen present, is filtered, slightly alkalised, with ammonia, and evaporated or crystallised, as before. Prop., . Colourle ; deliquescent; freely soluble in water, and in spirit; air and light turn it yellowish or brownish, with partial decomposition. It closely resembles iodide of pota ium, than which it is more active, and thought to be better suited to irritable and relaxed habits.— Dose , 1 to 10 or 12 gr.