29. Sulphurets of bismuth.
Protosulphuret. Bismuth combines with sulphur by heat, in the manner already described in the account of tin sulphurets. I found 100 parts bismuth in this way combine with 22 sulphur after 4 operations: this is therefore the protosulphuret or 1 atom bismuth (62) with 1 of sulphur (14). It may also be formed by substituting the oxide of bismuth for the metal. It has a dark brown or black metallic appearance, much like that of tin. It yields sulphuretted hydrogen in heated muriatic acid.
Hydrosulphuret of bismuth. When a solution of bismuth in nitro-muriatic acid is dropped into hydrosulphuret of lime, a black powder precipitates, which, when dried in the common temperature, appears to be hydrosulphuret of bismuth, or one atom sulphuretted hydrogen and one oxide of bismuth. It yields sulphuretted hydrogen by cold muriatic acid. But if the precipitate be dried in a heat of about 200°, the atom of water seems to be expelled, and there remains only the protosulphuret. Thus I found 69 parts oxide of bismuth unite to 15 sulphuretted hydrogen to form 84 hydrosulphuret of bismuth, when dried in the air; but upon being heated a little, it lost 8 parts of water and was reduced to the protosulphuret, retaining in great part the same appearance as before.
Deutosulphuret and trisulphuret of bismuth with oxygen. When nitro-muriate of bismuth is thrown into water the oxide is precipitated; if the acid water be decanted, quadrisulphuret of lime be put to the moist oxide and due agitation be used, the oxide abstracts sulphur from the lime so as to obtain 2 or 3 atoms for each one, if the sulphur be sufficient in quantity. To 6 oz. water I put 100 grain measures of 1.286 nitro-muriate, which I knew from its formation contained 20 oxide; after the precipitate had subsided I poured off 5 oz. of acid water, and to the remaining precipitate diluted with water I put 300 of 1.056 sulphuret of lime and agitated for 10 minutes. There were obtained 33 grains of brownish black sulphuret of bismuth dried for some hours in a temperature of 120°. I put the above 33 grains into a gas bottle with 100 muriatic acid and boiled it; there were obtained only 2 or 3 cubic inches of sulphuretted hydrogen, the oxide was dissolved and sulphur liberated; the sulphur collected and dried weighed 9 grains, and the oxide precipitated again from the muriatic acid by water and dried, weighed 17 grains, besides loss. From this it is evident the oxygen of the oxide must have been chiefly retained in the compound, and must have united to 2, and in great part to 3, atoms of sulphur. For 20 oxide would require 12 sulphur to form trisulphuretted oxide; and there was evidence of its having nearly, if not wholly, that quantity.
30. Sulphurets of antimony.
Protosulphuret. This is a natural production, and found in the state of a dark grey mineral of metallic appearance, and of the sp. gr. 4.2. It may also be formed artificially by uniting metallic antimony and sulphur by heat. Most authors nearly concur in assigning to it 74 parts antimony and 26 sulphur, per cent. That is, 1 atom antimony (40) and 1 of sulphur (14). It yields sulphuretted hydrogen by muriatic acid and heat, and a solution of the metallic oxide is obtained.
Hydrosulphuret. When antimony is precipitated from a solution, by sulphuretted hydrogen or a hydrosulphuret, or from an alkaline solution of the sulphuret by an acid, it appears in the form of an orange yellow powder, denominated golden sulphuret. It is constituted of 1 atom sulphuretted hydrogen and 1 of protoxide of antimony; it readily yields sulphuretted hydrogen by muriatic acid, and the oxide combines with this acid. Exposed to heat, water is expelled and protosulphuret left. It is constituted of 40 antimony, 7 oxygen, 14 sulphur and 1 hydrogen; or of 54 protosulphuret and 8 water.
Bisulphuretted, trisulphuretted and quadrisulphuretted oxide of antimony. When crystallized muriate of antimony is agitated along with dilute quadrisulphuret of lime, an orange yellow compound is formed, consisting of the oxide and sulphur. To 350 quadrisulphuret of lime, diluted with lime water, I put 22 grains moist crystals of muriate, and agitated well for some time. Got 26 grains dry yellow sulphuret, which heated burned blue, and left from 13 to 14 black grey sulphuret, equal to 10 antimony nearly; hence it must have been a quadrisulphuret, or rather sulphuretted oxide; for, by heating this compound in muriatic acid, a solution is obtained and sulphur liberated without the extrication of gas. Less of the sulphuret of lime would have produced a sulphuret of the same colour, but containing less of sulphur; so that it is evident various proportions may exist in combination. Instead of the crystallized muriate, the recently precipitated oxide, nearly free from acid, may be used to produce these compounds.
31. Sulphuret of tellurium.
Tellurium unites with nearly its weight of sulphur, by heat, according to Davy. It is probable that as usual in such cases, a protosulphuret is formed. This would lead to the conclusion that the atom of tellurium is only equal in weight to that of sulphur; which does not accord with results from the other combinations of tellurium, and hence the above fact may not perhaps be sufficiently ascertained.