Calcium sulphide

These are similar to those of the alkali metals but are rather less soluble in water. However, calcium sulphide, for example, is not precipitated by addition of sulphide ions to a solution of a calcium salt, since in acid solution the equilibrium position... 

Ammonium sulphide) Barium sulphide Calcium sulphide Chromium (II) sulphide Copper (II) sulphide Diantimony trisulphide Dibismuth trisulphide Dicaesium selenide Dicerium trisulphide Digold trisulphide Europium (II) sulphide Germanium (II) sulphide Iron disulphide Iron (II) sulphide Manganese (II) sulphide Mercury (II) sulphide Molybdenum (IV) sulphide... 

Calcium sulphide creates very violent detonations with chlorate or potassium nitrate. 

Techniques similar to that discussed earlier for the desulphurisation of coal have been used. Treatment of sulphur containing coke with lime can yield calcium sulphide which can be converted back to lime with generation of H2S by hydrolysis. 

J. J. Berzelius melted sulphur with an excess of potassium hydroxide and found the product to be a mixture of the monosulphide and thiosulphate. J. Kircher passed hydrogen sulphide over coarsely powdered sodium hydroxide at 100°. M. J. Fordos and A. Gelis made sodium sulphide by heating sodium carbonate with sulphur to 275° the product is obviously a kind of soda-liver of sulphur. J. W. Kynaston melted sodium hydroxide With calcium sulphide and J. V. Esop, and C. Vincent treated a soln. of barium or other sulphide with sodium or potassium... 

J. A. C. Gren observed that an aq. soln. of sodium sulphide is decomposed by carbon dioxide forming sodium carbonate with the evolution of hydrogen sulphide and if the stream of carbon dioxide be continued, sodium bicarbonate is formed. Over fifty patents based upon these observations were obtained. E. Berl and A. Rittener have studied the action of carbon dioxide upon sodium and calcium sulphides. The reaction is by no means simple, for a great proportion of the sodium is converted into bicarbonate before the whole of the sodium sulphide has been decomposed indeed, hydrogen sulphide still escapes even in the advanced stage of the process, where the sodium is almost entirely present as bicarbonate, and the... 

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... 

In the early days black ash was sent direct to the soap-makers and for a time was known as British barilla. The product deteriorated rapidly when kept, and does not now appear as an article of commerce. Black ash contains 40 to 45 per cent, of sodium carbonate 30 to 33 per cent, of calcium sulphide 2 to 6 per cent, of calcium oxide 6 to 10 per cent, of calcium carbonate. G. E. Davis 4 gives for the analysis of a sample ... 

The action of water on black ash during the washing involves a complex series of chemical changes which have been studied by J. Kolb, A. Scheurer-Kestner, and J. Pelouze. Calcium sulphide with water gradually forms soluble calcium hydrosulphide 2CaS+2H20=Ca(SH)2+Ca(0H)2. Sodium chloride decreases... 

It was generally supposed that the removal of carbon disulphide from crude coal gas when purified by lime was due to its absorption by calcium sulphide with the formation of calcium thiocarbonate, but Yeoman2 suggests that it is the perthiocarbonate, CaCS4, which is formed. This suggestion accounts for the necessity of the presence of some oxygen in order that absorption may take place. 

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. 

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