4084. Chloride of Platinum

4084.     Chloride of Platinum. The commercial chloride of platinum is the bichloride, formed by dissolving platinum in nitro-muriatic acid (aqua-regia), and evaporating the solution to dryness at a gentle heat. It is reddish-brown, deliquescent, and very soluble in water and in alcohol, yielding orange-colored solutions. ( Cooley.) (See No. 3220 (To Prepare Nitro-Muriate (Chloride) of Platinum).)

4085. Protochloride of Platinum

4085.     Protochloride of Platinum. This is formed by exposing the dried and powdered bichloride (see No. 4084 (Chloride of Platinum)) for some time to a temperature of 450° Fahr. It is a greenish-grey, powder, insoluble in water, but soluble in muriatic acid.

4086. Ammonio-Chloride of Platinum

4086.     Ammonio-Chloride of Platinum. A solution of sal-ammoniac is added to a strong solution of bichloride of platinum (see No 4084), avoiding excess; the precipitate is collected on a filter, washed with a little weak alcohol, and dried at a heat not exceeding 180° Fahr. It consists of minute, transparent, yellow crystals, very feebly soluble in water, less so in dilute alcohol, and insoluble in acids. By heating to redness, it is converted into spongy platinum. (See No. 3336 (Spongy Platinum).)

4087. Tests for Solutions of Platinum

4087.    Tests for Solutions of Platinum. Sulphuretted hydrogen throws down from neutral and acid solutions of platinum, a blackish-brown precipitate, which is only formed after a time in the cold, but immediately on heating the liquid. Sal-ammoniac and chloride of potassium give yellow crystalline precipitates, insoluble in acids, but soluble in excess of the precipitant, upon the application of heat, and decomposable by heat, with production of spongy platinum. Ammonia and potassa also give similar precipitates in solutions previously acidulated with hydrochloric acid. (Cooley).

4088. Subacetate of Copper

4088.    Subacetate of Copper. A green or bluish-green powder, better known as verdigris. This may be made by spreading the marc of grapes, or pieces of cloth dipped in crude acetic acid, upon plates of copper, with exposure to the air for several weeks. (Fownes.)

4089. Binacetate of Copper

4089.    Binacetate of Copper. Verdigris, dissolved in vinegar with the aid of heat, forms dark green or blue crystals of binacetate of copper. This is the commercial acetate of copper.

4090. Ammonio-Sulphate of Copper

4090.    Ammonio-Sulphate of Copper. A dark blue pulverulent substance, formed by rubbing together 1 ounce sulphate of coppper and 1/2 ounce sesquicarbonate of ammonia, until carbonic acid ceases to be evolved; then drying the product, wrapped in bibulous paper, in the air.

4091. Nitrate of Copper

4091.    Nitrate of Copper. This consists of deep blue, very deliquescent crystals, obtained by dissolving pure copper in dilute nitric acid. (See No. 97 (To make Nitrate of Copper Solution).)