4132. Sulphuret of Antimony

4132.    Sulphuret of Antimony. The black sulphuret (tersulphuret) of antimony is prepared from commercial sulphuret of antimony or by elutriation, in the same manner as directed for prepared chalk. (See No'. 1292.) The commercial sulphuret is obtained from tho native gray antimony ore by fusion; this separates tho sulphuret from the less fusible earthy matter; it is then run into cakes. (Cooley.)

Mixtures of an acidulated menstruum or syrup with a sulphuret of antimony, are apt to disengage sulphuretted hydrogen, when there is much of them, if kept in a warm room. Tho rule should bo to prepare as small a quantity as possible, and to keep tho bottle cool. (Eymael.)

4133. Penta-Sulphuret of Antimony

4133.   Penta-Sulphuret of Antimony. Called also golden sulphuret of antimony. Boil together for some hours 72 parts tersulphuret of antimony, 68 parts dry carbonate of soda, 52 parts fresh hydrate of lime, and 13 parts sulphur; filter, evaporate, and crystal-lize. Redissolve the crystals (Schlippe's salt), add dilute sulphuric acid, collect the golden floculent precipitate, wash it with cold distilled water, and dry with a gentle heat. (Liebig.)

4134. Nitrate of Bismuth

4134.    Nitrate of Bismuth. The neutral nitrate is made from 2 ounces pure bismuth broken into fragments, dissolved by-heat in 6 ounces nitric acid, adding more acid, if necessary, to effect entire solution. Add to the solution half its volume of distilled water, filter through powdered glass, and crystallize by evaporation. (Cooley.)

4135. Subnitrate of Bismuth

4135.    Subnitrate of Bismuth. This is also called trisnitrate of bismuth, magistery of bismuth, and pearl white. It is insoluble in water, but freely soluble in nitric acid. Dissolve 2 ounces bismuth in 3 fluid ounces nitric acid, previously diluted with 2 fluid ounces distilled water; then add 3 quarts cold water, and allow the white precipitate to subside. Afterwards decant the clear liquor, wash the powder, and dry it by a gentle heat. (Br. Ph.)

4136. Oxide of Bismuth

4136.    Oxide of Bismuth. The anhydrous oxide is made by exposing the nitrate or Subnitrate to gentle ignition in a crucible. This is a straw-yellow colored powder. The hydrated oxide is a rich-looking white powder, obtained thus: Dissolve 2 pounds bismuth in 21/2 pounds nitric acid, and drop it gradually into a solution of 3 pounds carbonate of potassa in twice it weight of water, rendered caustic by previous treatment with quicklime (see No. 101 (To make Caustic Potash)); wash the precipitate well with cold water.

4137. Tests for the Salts of Bismuth

4137.   Tests for the Salts of Bismuth. Tin, copper, iron, and zinc throw down bismuth from its solutions in the metallic state. If a salt of bismuth bo heated with carbonate of soda by the flame of a blowpipe, a bead of the metal, surrounded by a crust of yellow oxide, is obtained. The brittleness of the bead under the hammer distinguishes it from lead. The salts of bismuth are mostly devoid of color; some are soluble, others insoluble. The soluble salts redden litmus paper; and, when the solution contains but little free acid, and is largely diluted with water, a subsalt, more or less soluble, is deposited. This property of forming subsalts is very characteristic. (Makins.)