Sulphide Of Antimony

This sulphide (per-sulphide) Sb2S5 is orange yellow. Heat decomposes it into sulphur and proto-sulphide. Hydrochloric acid dissolves it with disengagement of sulphydric acid and precipitation of sulphur. It is obtained by mixing a solution of perchloride of antimony with tartaric acid, and passing a current of sul-phydric acid through it. The precipitate is well washed, filtered, and dried at a gentle heat.

Oxy-Sulpiiides Of Antimony

When the sulphide of antimony is reduced to powder, and roasted until it has lost its metallic brightness, then melted, it produces an opalescent product with a vitreous break. It is a mixture of oxide and sulphide of antimony, which takes the name of crocus or liver of anti-mony, according to the proportion of sulphur it contains.

The crocus contains 1/5 of its weight of sulphur, and the liver of antimony 1/3. But as the oxide and sulphide can combine together in many proportions, it is evident that the composition of these two products must vary. The first has a yellowish-red, and the second a brown and tarnish-red color.

Sulphide Of Mercury

The sulphide of mercury (vermilion), as found in the trade, is sufficiently pure for the fabrication of matches.

The sulphide of mercury (HgS) sometimes exhibits a red color, more beautiful than that of sublimed cinnabar. Heat decomposes it into sulphur and mercury. Hydrogen, carbon, and many metals also decompose it. Nitric acid and aqua regia rarely attack it. In the fabrication of matches it is used for coloring.

Cyanide Of Lead

Cyanide of lead is obtained by adding a solution of cyanide of potassium to a solution of acetate of lead, and it forms a precipitate which is washed by decantation. The precipitate is then collected on a filter, and dried at a gentle heat.