The aqueous solution of hydrosulphuric acid is employed as a test of metals, and, more especially, for the discovery of minute portions of lead, with which it gives a dark-coloured precipitate of sulphide of lead : with the salts of antimony it gives an orange precipitate, and with arsenious acid a yellow one.
Hydrosulphuric acid forms salts which are termed hydrosulphates, and these are probably formed when it is combined with ammonia, potash, soda, and the alkaline earths ; but by metallic oxides, properly so called, it is decomposed, the results not being hydrosulphates of metallic oxides, but water and a metallic sulphide : this is the case with oxide of lead, silver, &c.
Persulphide of hydrogen (HS, ?). This compound cannot be formed by direct combination. To prepare it, equal weights of sulphur and recently slaked lime may be boiled in throe times their weight of water for half an hour. The result is a deep reddish-yellow coloured solution of persulphide of calcium, which, when clear and cold, is to be added to an excess of hydrochloric acid diluted with about twice its weight of water : by their mutual action sulphur is precipitated, accompanied by a yellow oil-like fluid, which is the persulphide of hydrogen. It is a viscid liquid, of a yellow colour, and of specific gravity about P77 ; its smell is similar to, but not so powerful as that of hydrosulphuric acid ; its elements are held together by a feeble affinity, so that even in the cold it is gradually converted into hydro sulphuric acid and sulphur, and this change is immediately produced at 212°.
Chlorine and Sulphur appear to form two compounds, the chloride and di-chloride. According to Dumas, when sulphur is acted upon by excess of chlorine, a neutral chloride is obtained, which consists of one equivalent of chlorine and one equivalent of sulphur (SCI).
It usually contains some di-chloride, from which it is to be purified by repeated distillation at about 140° Fahr.
It may be formed either by heating sulphur in excess of dry chlorine gas, or, at common temperatures, by passing excess of chlorine through a tube containing powdered sulphur.
Chloride of sulphur is liquid, has a reddish-brown tint, and a density of P62; that of its vapour being about Its boiling-point is 147°.
Di-chloride of Sulphur (S,C1).—This substanco was first obtained by Dr. Thomson. When chlorine gas is passed over powdered sulphur, gently heated, it gradually disappears, and the di-ehloride is formed by direct combination : the liquor obtained is to be distilled, and then possesses the following properties :—I It is liquid, and is red by reflected, and yellowish-green by transmitted light : it emits acrid fumes when exposed to the air ; its density is P628, that of its vapour being 4.7 ;
it is volatile below 200°, and boils at 280°. Dry litmus-paper is not altered by it. It is energetically decomposed by and decomposes water, the results being hydrochloric and hyposulphurous acids. It does not combine with alkalies.
Sulphur and Bromine. [BuomINE.] Carbon and Sulphur.—These form by direct action bi-sulphidc of carbon or sulphocarbonic acid.
It may be obtained either by passing the vapour of sulphur over charcoal heated to redness in a porcelain tube, or distilling a mixture of bi-sulphide of iron and one-sixth of its weight of charcoal. It may be condensed by being passed into cold water, and to free it from uncombined sulphur and moisture it should be rectified from chloride of calcium at a low temperature.
It is a colourless transparent liquid, of density P272, that of its vapour being ; it has an acrid pungent taste, and a very fetid odour ; its refractive power is very high ; it is insoluble in water, but combines with alcohol and ether, from which water precipitates it ; it is extremely volatile, boils at 115'5°, and is not rendered solid at the lowest obtainable temperature : owing to its great volatility, it produces sufficient cold under the exhausted receiver of the air-pump to freeze mercury : it is extremely inflammable, the results of its com bustion being carbonic and sulphurous acid gases, attended with a brilliant greenish-white flame. It combines with metallic sulphides to form a class of sulphur salts termed sulpho-carbonates ; for example, sulpho-carbonate of potassium (KS,CS,).
It is a remarkable circumstance that so volatile a liquid should he produced by the combination of two solid bodice. It was discovered by Lamp e(lilts in 179t3.
Phoepherws and Sulphur. [Pnosenones.] iodine and Saphar. [Ionise.] Sekniass and Suiphur. [SstessuN.] Boron asd k'slphar. [Bones.] 1phar Salts.—These are certain double sulphides. SO designated by Bone : the eleetro•negativo sulphides constituting seipher acids ; and the electro-positivo sulphides, Lases. Among the sulphur acid, are the sulphides of arsenic, antimony, tellurium, tin, &c.; and In this clue are also included sulphuretted hydrogen, bisulphide of carbon, and selenium and aulphoeyanogou the sulphur bases include the protoeulphides of the metals of the alkalies and alkaline earths.
Compounds formed by the union of sulphur acids with sulphur basea are the se/pher sans.
The close chemical analogy between sulphur and oxygen is further seen on considering the constitution and properties of the following compounds of the two elements.