Calcium polysulphide

In 1861, W. Gossage showed that calcium sulphide is insoluble in water, and is but little attacked by sodium carbonate he also showed that the residue left after the lixiviation of black ash is a mixture of calcium monosulphide and carbonate, even when no sodium sulphide is present in the liquor and that if any sodium sulphide be present in the liquor, it is derived from the formation of calcium polysulphides in the black ash which can be prevented by using an excess of limestone. Both J. W. Kynaston and W. Gossage showed that no sodium hydroxide is present in black ash because (a) sodium hydroxide melted with black ash forms calcium oxide and sodium carbonate and (b) no sodium hydroxide can be extracted with... 

Milk of Sulphur or Precipitated Sulphur of commerce, which is prepared by precipitating with acid a solution of calcium polysulphide (obtained by heating an aqueous emulsion of slaked lime with finely divided sulphur, see p. 67) or of liver of sulphur (obtained by fusing together potassium carbonate and sulphur), is also a mixture of finely divided rhombic sulphur with the insoluble amorphous y-sulphur. It owes the paleness of its colour and its especial suitability for internal medicinal application to its very fine state of division. y-Sulphur in reactivity is very little different from ordinary crystalline sulphur.7... 

Copper polysulphides.—An orange-red substance of the formula CuS3 is obtained by fusing cupric sulphate with sodium carbonate and sulphur. Heating with carbon disulphide converts it into an amorphous, dark-brown substance, Cu2Ss.4 Another polysulphide, Cu2S5, is stated to be formed by the interaction at 0° C. of a solution of cupric acetate and calcium polysulphide.5 It has a reddish-brown colour. It is doubtful whether any of these polysulphides is a true chemical compound. 

Fatty acid potassium salt (soft soap) Lime sulphur (calcium polysulphide)... 

The substances used for cleaning and roughening the surface of the stone so as to facilitate the absorption or adherence of the color are various. Alum, which doubtless comprised as with Dioscorides and Pliny salts of iron as well as of aluminum, is frequently used, although white alum is here often specifically mentioned. Urine is frequently used, its efficiency being doubtless due to the carbonate of ammonium formed on standing. Limewater, sodium carbonate, vinegar, and a solution of sulphur and lime (polysulphides of calcium) are other constituents of the mordanting solutions. 

Potassium, sodium and calcium sulphides are applied externally to soften the skin by dissolving the epidermis in diseases such as psoriasis, acne and seborrhea. Mixtures of calcium or potassium polysulphides and thiosulphate behave similarly and are also depilatories. Another common hair remover is barium sulphide, mixed with starch or zinc oxide, whereas selenium suphide and cadmium sulphide are applied topically, in shampoos, to control dandruff. 

Ammonium thiosulphate, (NH4)2S203.—A hydrate of the formula 8(NH4)2S203,H20 is produced by the interaction of ammonium carbonate and calcium thiosulphate in aqueous solution, and on concentration is deposited in the form of deliquescent needles or rhombic laminae.4 The anhydrous salt is formed by the action of sulphur dioxide on a solution of the sulphide,5 and is a by-product in the reduction of p-dinitro-benzene to p-nitroaniline by means of ammonium sulphide.6 It is also formed by the action of ammonium sulphate on ammonium polysulphides,7 and by that of ammonia on sulphur trioxide7 or sulphur.8 The monoclinic9 crystals decompose almost completely at 150° C., with production of ammonium sulphite, sulphur, ammonia, and hydrogen sulphide.10 It is employed in iodometry. 

Other materials Herbs, spices and extracts Flavouring substances identified in food Water Thiamine and thiamine hydrochloride Ascorbic, citric, lactic, fumaric, succinic and tartaric acid and their salts (Na, K, Ca, Mg, NH ) Guanylic acid, inosinic acid and their salts (Na, K, Ca) Inositol Sodium, potassium and ammonium sulphides, hydrosulphides and polysulphides Led thine pH regulators acetic, hydrochloric, phosphoric and sulphuric acid salts thereof sodium, potassium, calcium and ammonium Polymethylsiloxane... 

The polysulphide of calcium is prepared by boiling finely ground sulphur with newly slaked lime and siifiBcient water. It is advantageous to add to this solution of polysulphide a certain proportion of powdered oxysulphide of calcium, which is the residue of the lixiviation of crude soda. In the absence of oxysulphide, quicklime may be added. 

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