Contractions. - Bism. Bis.
Synonym. - Bismuthi magisterium.
Present name. - Bismuth Subnitrate. Bi2O3, 2Hno3.
The British Pharmacopoeia gives the following process for preparing this: -
Purified Bismuth, in small pieces
Nitric Acid . . . .
4 fluid ounces;
Distilled Water . . .
. A sufficiency.
Mix the Nitric Acid with 3 ounces of distilled water, and add the Bismuth in successive portions. When effervescence has ceased, apply for ten minutes a heat approaching that of ebullition, and decant the solution from any insoluble matter that may be present. Evaporate the solution until it is reduced to 2 fluid ounces, and pour it into half a gallon of distilled water. When the precipitate which forms has subsided, decant the supernatant liquid, add half a gallon of distilled water to the precipitate, stir them well together, and after two hours decant off the liquid, collect and drain the precipitate in a calico filter, press it with the hands, and dry it at a temperature not exceeding 150°.
Characters and Tests. - A heavy white powder in minute crystalline scales, blackened by Sulphuretted Hydrogen; insoluble in water, but soluble in Nitric Acid mixed with half its volume of distilled water, forming a solution which, poured into water, gives a white precipitate. It forms with Sulphuric Acid diluted with an equal bulk of water a solution which is blackened by Sulphate of Iron. The Nitric Acid solution gives no precipitate with diluted Sulphuric Acid, nor with solution of Nitrate of Silver.
Preparation. - Trituration.
Reference to Horn. Proving. - R. A. M. L., vi.
Proper forms for dispensing. - 1x to 3, Trituration only. 4, dilute Tincture only. 5 and upwards, Tincture, Pilules, or Globules.