SECTION 14.EARTHY, ALKALINE AND METALLICSULPHURETS.
The sulphurets exhibit a very important class of combinations of two elements. Many of the metals are found chiefly in the state of native sulphurets, and are extracted by particular processes. Artificial combinations of sulphur and the metals, and of sulphur and the earths and alkalies are commonly practised, and are found useful in chemicalinvestigations. The alkaline and earthy sulphurets will scarcely be allowed perhaps to be combinations oftwo elementsonly; but their analogy with the other compounds is such as to induce us to treat of them under this head, especially as they are agents occasionally in the formation of metallic sulphurets, and these cannot be so well understood without some knowledge of the other. For like reasons the compounds of three elements, sulphur, metal, and oxygen, called sulphuretted oxides, and sulphuretted sulphites, and those of four elements, sulphur, metal, oxygen and hydrogen, called hydrosulphurets, may be considered at the same time, having an intimate relation with the sulphurets strictly so called, or the compounds formed with sulphur and the undecompounded bodies.
Sulphur may be combined with the earths, alkalies and metals, by heat, of various degrees according to the nature of the subjects. The union is attended in many cases with a glowing ignition, indicating the evolution of heat. The metallic oxides and sulphur when heated together commonly produce a sulphuret of the metal, whilst the oxygen escapes with part of the redundant sulphur in the form of sulphurous acid, and the rest of the sulphur sublimes.
In the humid way sulphur may be combined with earths, alkalies, and metals, by means of sulphuretted hydrogen, hydrosulphurets (that is, sulphuretted hydrogen united to other alkaline or earthy bases), and hydroguretted sulphurets (a name given to certain earthy and alkaline sulphurets formed mostly by boiling mixtures of the respective bases and sulphur in water.) The sulphuretted hydrogen may be used in this state of gas or combined with water; the hydrosulphurets and hydroguretted sulphurets are best applied in their watery solutions. The metals are to be used in this case in the state of salts, that is, oxides united to acids, and in solution; or their oxides may in some instances be precipitated previously to the addition of the sulphur compound; the alkalies and earths are sometimes directly sulphurized in the state of hydrates, and at other times by double affinity, in the state of salts or combined with acids. The phenomena in the case of sulphurets formed in the humid way, are various and often complicated, and the true results are not always to be obtained without considerable difficulty and uncertainty.
When pounded lime and sulphur are mixed together, and heated in a crucible scarcely any union takes place; the sulphur sublimes or burns away and leaves the lime unaltered. If for lime we substitute carbonate of lime, it also remains unaltered. But if hydrate of lime and sulphur are heated together in equal weights, the hydrate is decomposed, and the lime unites to a portion of the sulphur, whilst the excess of sulphur sublimes or burns and escapes at a low red heat. The residue, about 60 per cent. of the original weight, is a yellowish white powder, composed of sulphur and lime. If this be again treated with sulphur and heated, it undergoes no material change; the last sulphur entirely escaping, leaves the sulphuret unaltered, and hence shews that it must be a true chemical compound.
Now if 32 parts hydrate of lime, which consist of 24 lime and 8 water, be mixed with 32 sulphur and heated as above, they will yield 38 parts sulphuret, which must be composed of 24 lime and 14 sulphur, or sulphurand water; but it appears from the analysis hereafter to be given, that the whole of this last part is sulphur; therefore the compound is formed of 1 atom of lime, and 1 of sulphur, and is theprotosulphuretof lime.
When 32 parts of common hydrate of lime and 56 sulphur, are boiled together in 1000 parts water for half an hour, or more, occasionally adding water to supply the waste, a fine yellow liquid is obtained, with a few grains of residuum containing both lime and sulphur nearly in the original proportion with a few grains of alumine. This liquid of course contains in solution, a combination of 1 atom of lime, or perhaps hydrate of lime, and 4 atoms of sulphur; and may therefore be called aquadrisulphuretof lime. If more sulphur or lime than the above proportion be used, the surplus will remain in the residuum uncombined, shewing that by this process no other than a quadrisulphuret can be formed. A similar solution may be obtained in cold water by frequent agitation; but it is much slower in producing the effect. The strength of liquid quadrisulphuret depends upon the relative quantity of the ingredients. I have boiled it down till the water was only 5 times the other materials, which appears to be itsmaximum strength in the common temperature; its specific gravity was 1.146; but in general I have used it of less than 1.07 density. It may be proper to remark here that I find the decimals multiplied by 4 express very nearly the number of grains of lime in 1000 grains measures of the solution, and multiplied by 9 those of the sulphur; on this account a solution of the sp. gravity 1.06 facilitates the calculations, as 100 measures of it contain 2.4 grains of lime, and 5.4 or 5.6 of sulphur nearly.
It is rather surprising that no bisulphuret nor trisulphuret of lime should be formed this way. One would suppose that the sulphuret of lime in its progressive changes would have passed through the forms of bisulphuret, &c. till it had obtained its maximum of sulphur when that was in excess; but, as has been observed, the quadrisulphuret is the only one formed, whatever may be the proportions of the ingredients. I imagine the reason to be, that the sulphur has to decompose the hydrate of lime, and that no fewer than 4 atoms of sulphur are adequate to that effect; it is known that water adheres so strongly to lime as to require a red heat to separate it. When therefore we mix lime water with quadrisulphuret of lime, it must be considered as a mere mixture of the two, and that the lime does not divide the sulphur equally.Consistently with this reasoning, whenever the lime is in excess in forming quadrisulphuret of lime, we ought to consider the liquid solution aslime waterholding quadrisulphuret of lime. This distinction will be of some importance when the solution is weak, because then the lime in the lime water will be considerable, compared with the lime combined with sulphur.
1.Protosulphuret.The properties of this compound are;—about 1 grain is soluble in 1000 water; this water, as well as the powder itself, tastes like the white of an egg; salts of lead are thrown down black by the solution; weak nitric and muriatic acids dissolve the lime, and leave the sulphur; 100 parts of test acid require 19 of the powder, and yield 7 of sulphur; indicating the compound to be 12 lime and 7 sulphur. The same conclusion may be obtained by means of a solution of lead; if water containing 1.9 grains of the powder be precipitated by nitrate of lead, it will require 7 grains of the salt = 2.2 acid and 4.8 oxide, or 4.5 lead, and about 5 or 5½ grains of sulphuret of lead will be formed, and the liquid will contain 3.4 grains of neutral nitrate of lime.
2.Quadrisulphuret.This combination has been long known, andsome of its properties observed; but I have not found in authors any determination of its proportions. It is of a beautiful yellow or orange colour, and 1 grain imparts very sensible colour to 1000 of water; it has a disagreeable bitter taste; when evaporated down, it crystallizes or rather perhaps solidifies into a yellowish mass; but its properties are affected by the process from the acquisition of oxygen. This mass when dried, burns with a blue flame and loses 40 per cent.; the remainder is a white powder, a mixture of sulphite and protosulphuret of lime. Liquid quadrisulphuret exposed to the atmosphere soon becomes covered with a white film which arises from the sulphur displaced by oxygen gas; this film being broken subsides, and another is formed, and so on successively till at length the acquisition of oxygen ceases with the deposition of sulphur, and the liquid remains quite colourless. It is intensely bitter, and contains lime, sulphur and oxygen in proportions to be presently determined. This colourless liquor undergoes a gradual change by being kept for years in a bottle with a common cork; a deposition of some sulphur and sulphate of lime takes place, but whether from a further acquisition of oxygen gas or from some internal chemical action, I have not had an opportunity of observing.
From the above observations it is obvious that to formpurequadrisulphuret of lime the atmospheric air should be excluded, as the agitation by ebullition would promote the oxidizement of the compound. I mixed 168 grains of sublimed sulphur with 96 hydrate of lime, which by previous trials I had found to consist of 70 lime including 2 or 3 grains of alumine, and 26 water; the mixture was put into a small florence flask, which was then filled with water up to the neck and loosely corked. This was immersed in a pan of water and boiled for 2 or 3 hours, the flask was continually turned round to agitate the mixture and promote the solution. After the undissolved part had subsided the clear liquor was decanted and found to be 2800 grain measures of the sp. gr. 1.056; the residuum moderately dried weighed 34 grains; it was found to contain 8 of lime and alumine, and 25 of sulphur. Hence the liquid contained 62 lime and 143 sulphur, or 2.2 lime and 5.1 sulphur per cent.; that is, after the rate of 24 lime to 56 sulphur, or 1 atom of lime to 4 of sulphur, and its weight = 80, the atom of sulphur being supposed 14. Here then we have a synthetic proof of the composition being a quadrisulphuret. Innumerable other experiments, though madewith less rigid accuracy, had convinced me that the liquid is essentially the same whatever the proportions of the ingredients, and that the residuum only varies in such cases.
I have made many experiments occasionally since 1805, on the quantities of oxygen absorbed and sulphur deposited by quadrisulphuret of lime. They all concur in establishing the same conclusion; namely, that each atom of the compound takes 2 of oxygen and deposits 2 of sulphur, in its transformation from the yellow to the colourless state. For instance, 100 measures of the above 1.056 took 900 of oxygen gas = 1.22 grains, and let fall 2 grains of sulphur, besides a small portion which adhered to the bottle, which was estimated at a few tenths of a grain. The method is to put 100 measures into a graduated and well stoppered bottle filled with oxygen; to agitate briskly for half an hour, occasionally opening the stopper a little under water to admit its entrance into the place of the oxygen absorbed. Whenever the agitation has been continued for five minutes without any sensible increase in absorption, and the liquor, after standing to let the sulphur subside, appears colourless, the experiment is finished. This new combination then consists of 1 atom lime, 2 sulphur, and 2 oxygen = 66; it will benecessary to give it a name: I propose calling it sulphuretted sulphite of lime, as it is an atom of sulphur united to sulphite of lime; and the rather, as it will appear in the sequel that other neutral salts do combine occasionally with an atom of sulphur. This sulphuretted sulphite may be boiled down to the sp. gr. 1.1 before it precipitates: the liquid then contains about 12 per cent. of the salt, or 5 sulphur, 2½ oxygen, and 4½ lime. The salt precipitates from the liquid by evaporation in the form of a white powder; it burns with a feeble blue flame, and loses about 20 per cent.; the remainder is sulphite of lime. When 100 grain measures of the liquid sulphuretted sulphite (1.1) are saturated with oxymuriate of lime, they acquire 5 grains of oxygen, and then yield 12½ grains of sulphuric acid (containing 5 sulphur and 7½ oxygen), as may be found by the barytic tests. The point of saturation is known by the smell of oxymuriatic acid being given out permanently.
If however we oxidize the quadrisulphuret of lime by oxymuriate of lime, the results are somewhat different. As soon as an atom of the quadrisulphuret has received two atoms of oxygen it becomes colourless as before, but ¾ of the sulphur is thrown down instead of ½; and whenmore oxymuriate is added, so as to impart 3 atoms of oxygen to one of the salt, a complete sulphate of lime is formed. The point of saturation is determined by adding a small portion of muriatic acid to the liquid, which develops the oxymuriatic acid as soon as it becomes in excess. This method excels in the analysis of the alkaline and earthy sulphurets in general.
When quadrisulphuret of lime is treated with an alkaline carbonate, a reciprocal change takes place; the carbonic acid takes the lime, and the alkali the sulphur, leaving however 1 atom of sulphur with the carbonate which precipitates. Hence a sulphuretted carbonate of lime is obtained and a trisulphuret of the alkali. The sulphur burns off from the carbonate below a red heat and leaves 75 per cent. of carbonate of lime; this affords an excellent analysis of quadrisulphuret of lime as far as lime is the object. Thus 540 of the above 1.056 quadrisulphuret took 100 test carbonate of potash (1.25), and gave a precipitate of 29 grains, which burned blue and left 22 grains = 12 lime, and 10 acid; but if 540 ∶ 12 ∷ 100 ∶ 2.2, as above determined synthetically: moreover, 12 lime, 10 acid, and 7 sulphur, are as 24 lime, 20 acid, and14 sulphur; the composition of an atom of sulphuretted carbonate of lime, which is analogous to the sulphuretted sulphite of lime, as found above.
When quadrisulphuret of lime is treated with as much sulphuric acid as is sufficient for the lime, the sulphur is in part precipitated, but it is in union with the sulphate of lime, or at least they are not separable by mechanical means. This compound is sold in the shops under the name of precipitated sulphur. It is about one half sulphate of lime, and the other half sulphur. The nitric and muriatic acids precipitate the sulphur partially from quadrisulphuret, but the sulphur assumes a viscid form and exhales sulphuretted hydrogen, and the proportion of the elements of quadrisulphuret are not easily obtained by any of these acids.
The mutual action of quadrisulphuret of lime, and the metallic salts is curious and interesting; for instance, with nitrate of lead. Let a solution of nitrate of lead, containing 97 oxide, be treated with a solution of quadrisulphuret of lime by degrees, as long as a black precipitate appears, marking the exact point of saturation; this will be found when 36 parts of lime have entered, and 84 of sulphur; the sulphuret of lead will fall, and when dried will weigh 145 parts, andcontain 90 lead, and 55 sulphur; that is, 1 atom of lead, and 4 of sulphur, and is consequently a quadrisulphuret of lead. The liquid remains clear and colourless, and contains the nitric acid, lime, oxygen of the lead, and ⅓ of the sulphur; each atom of nitric acid combines with one of lime, which retains one of the 4 atoms of sulphur, forming a sulphuretted nitrate of lime, consisting of 45 acid, 24 lime, and 14 sulphur; the 7 parts of oxygen unite with 7 of sulphur to form sulphurous acid, which require 12 parts of lime to saturate them and 7 of sulphur, forming a sulphuretted sulphite of lime: hence we see that 28 parts of sulphur remain in the liquor, and the rest (56) unite with the lead. If now we add gradually more nitrate of lead, a silvery white precipitate appears, increasing till half the original quantity is added, and then the liquid is saturated. This white precipitate is sulphuretted sulphite of lead; when heated it soon grows black and loses 15 or 20 per cent., being then a protosulphuret of lead. The liquid now contains sulphuretted nitrate and simple nitrate of lime; nitrate of lead has no effect, but nitrate of mercury precipitates a black sulphuret.
Quadrisulphuret of lime saturated with oxygen, as has been observed,contains sulphuretted sulphite of lime in solution, and deposits sulphur: the liquid treated with nitrate of lead, gives as above the white, silvery sulphuretted sulphite of lead as a precipitate, and holds nitrate of lime in solution.
Hydrosulphuret of lime.This compound may be formed by passing sulphuretted hydrogen into lime water; the water assumes a brownish colour, but the point of saturation is not easily found, as the lime water is not neutralized so as to shew by the colour test, and water of itself absorbs above twice its volume of the gas. By means of a neutral solution of nitrate of lead it may be found that 1000 lime water in volume, require about 600 sulphuretted hydrogen, because then a mutual saturation is observed by double affinity; that is, sulphuret of lead and neutral nitrate of lime are formed; but otherwise the liquid remaining is either acid or alkaline. Hydrosulphuret of lime, as well as the other hydrosulphurets, has a peculiar bitter taste. It forms a useful reagent in regard to metals, but is apt to be spoiled by keeping, owing to the acquisition of oxygen.
I have not succeeded in endeavouring to combine sulphur and magnesia in the dry way; but a liquid sulphuret is easily formed by the action of double affinity.
Let a quantity of the liquid quadrisulphuret of lime be treated with a solution of sulphate of magnesia, so that the sulphuric acid may be sufficient for the lime; by digesting in a moderate heat, the sulphate of lime is precipitated, carrying with it one fourth of the sulphur, and a trisulphuret of magnesia remains in solution. I have not observed any remarkable feature of distinction between this sulphuret and that of lime, except as above noticed in the proportions of their compounds.
Hydrosulphuret of magnesia.This compound may be formed by pouring sulphuretted hydrogen water into recently precipitated magnesia; it does not differ much from that of lime. One atom of sulphuretted hydrogen (15), combines with one of magnesia (17), and the compound is soluble in water.
Protosulphuret.The protosulphuret of barytes may be procured the same way as that of lime, by heating hydrate of barytes and sulphur till the mixture becomes red. It is very little soluble in water, and accords in other respects with the like compound of lime. It consists of 68 barytes and 14 sulphur, or 100 barytes and 20½ sulphur.
Quadrisulphuret.The quadrisulphuret of barytes may be formed the same way as quadrisulphuret of lime, by boiling the hydrate of barytes and sulphur together. A yellow solution of the compound is formed, not distinguishable in appearance from that of lime; and it appears to be analogous to it in most of its properties. By acquiring oxygen it becomes colourless sulphuretted sulphite of barytes, and crystalizes in needles; in this last respect it differs from that of lime. The maximum density of liquid quadrisulphuret I have not had an opportunity of ascertaining; it is 1.07 or upwards; that of the liquid sulphuretted sulphite is much less than that of lime; the crystals are found in a liquid so low as 1.004 sp. gr. They have a fine silky lustrewhen dry, and a yellowish colour; heated they burn with a blue flame and leave a white mass of sulphate preserving the same crystalline appearance as before, and lose about 20 per cent. of weight. Ten grains of the crystals of sulphuretted sulphite, when treated with liquid oxymuriate of lime to saturation, require 2+ grains of oxygen and yield 8 grains of sulphate of barytes, together with an excess of sulphuric acid which with muriate of barytes gives 8 grains more of sulphate. From these facts it may be concluded that the sulphuretted sulphite consists of one atom barytes, 2 sulphur, 2 oxygen, and 2 water, and that 4 more of oxygen are derived from the oxymuriatic acid to convert the sulphurous oxide into sulphuric acid. The sulphuretted sulphite of barytes seems to pass into sulphate by length of time. The weight of the atom of quadrisulphuret of barytes is 124; the compound in mass consists of 100 barytes and 82 sulphur.
Hydrosulphuret of barytes.This compound may be formed in the same manner as that of lime, and is found to have similar properties. The proportions for mutual saturation are, I find, as in the case of lime, 15 sulphuretted hydrogen to 68 barytes by weight, or one atom of each.
The protosulphuret and quadrisulphuret of strontites may be formed in the same way as those of lime and barytes. From a few experiments made on these compounds I have not observed any remarkable feature of distinction between them and the corresponding ones of the other earths.
Hydrosulphuret of strontites.This compound may be formed in the same way as that of lime; the proportions to produce mutual saturation will be 1 atom of each, or 15 parts sulphuretted hydrogen, to 46 strontites by weight.
I made several unsuccessful attempts to combine alumine and sulphur. When alumine and sulphur mixed together are heated, the sulphur sublimes chiefly, and leaves the alumine with traces of sulphate of alumine.
In the humid way, recently precipitated and moist alumine mixed withsulphur and boiled in water, give a liquid with some traces of sulphuric acid, but no sulphuret of alumine; the sulphur and alumine both subside, and when the sulphur is either sublimed or burnt, the alumine remains much the same as at first. When a solution of alum is treated with sulphuret of lime, sulphate of lime is precipitated along with the greatest part of the sulphur in a kind of feeble union rather than mechanical mixture, it should seem; the alumine is at the same time precipitated probably in mechanical mixture; there remain in solution a little sulphuret of potash and sulphate of lime.
Sulphuret of silexis not known, I apprehend, to exist. When silicated potash in solution is treated with quadrisulphuret of lime, a copious dark brown or black precipitate instantly appears; the liquid when filtered is of a pale yellow colour, and seems to contain about one half of the sulphur and potash, whilst the other half is thrown down in union with the lime and silex. This black compound is probably 1 atom of lime, 2 of sulphur, 2 of potash, and 2 of silex; it cannot therefore be accounted a sulphuret of silex.
Sulphurets of yttria,glucine, andzircone, are as yet, I presume, unknown.
Potash has a strong affinity for sulphur and unites with it in various ways and proportions.
1st.In the dry way by heat.When either pure potash or the carbonate (salt of tartar) is heated in a covered crucible with sulphur, a chemical union of the two principles takes place. Eight parts of dried hydrate of potash unite to six or seven of sulphur: a heat of 4 or 500° of Fahrenheit is convenient for the purpose. If the carbonate of potash be used, then 12 parts dried in a low red heat will require 8 of sulphur for their complete saturation: in this case a higher degree of heat is requisite in order to expel the carbonic acid; a low red heat seems sufficient from my trials. When the heat does not exceed 3 or 400° a partial union takes place; the carbonate of potash, without losing any acid, unites to ⅓ of the sulphur, and the rest of the sulphur remains uncombined; when intermediate degrees of heat are used, I have found the result a mixture of the pure sulphuret and the carbonated sulphuret, with more or less of sulphate of potash. A high degree of heat and exposure to the atmosphere produces a sulphateinstead of a sulphuret. The sulphurets obtained this way are in fusion till poured out and cooled; they are of alivercolour, and hence were formerly calledliversof sulphur. They are largely soluble in water, and give a brownish yellow solution.
2d.In the humid way by solution.Pure caustic potash in solution when boiled with sulphur dissolves it largely, 42 parts of real potash being saturated with about 56 of sulphur. If we boil a solution of carbonate of potash with sulphur, for an hour or more, a brown liquor is obtained, which consists of 60 parts carbonate of potash and 14 sulphur in chemical union.—It has already been observed that a trisulphuret of potash may be obtained by double affinity from quadrisulphuret of lime and carbonate of potash, together with sulphuretted carbonate of lime.
From what has been stated we may infer at least three varieties in the compounds of sulphur and potash, viz.
1st.Sulphuretted carbonate of potash.This consists of 1 atom carbonate of potash (61) with 1 atom of sulphur (14). Its analysis may be effected as follows: the quantity of carbonic acid may be found by the lime water necessary to saturate it; the potash may be known fromthe quantity previously entering into the mixture; and the sulphur in the same manner, or from the quantity of sulphuretted carbonate of lead that it forms.—The sulphur may also be known, from the quantity of oxygen it requires by means of oxymuriate of lime to produce saturation; this I find to take place when the oxygen is half the weight of the sulphur, or one atom to one of sulphur; it soon happens, that one atom of sulphur deprives two others of their oxygen, and sulphuric acid is formed whilst the other two atoms of sulphur join the carbonate of lime and are precipitated along with it. As it may frequently happen, that the sulphuretted carbonate is mixed with common carbonate of potash, the proportions may be found by means of nitrate of lead, which being cautiously dropped into the solution, lets fall first the brown sulphuretted carbonate of lead, and then the common white carbonate of lead.
The sulphuretted carbonate of potash absorbs oxygen and precipitates metals much the same in appearance as the other sulphurets; but essential distinctions are observable, some of which are noticed above, and others will appear in the sequel.
2 and 3. Thetrisulphuretandquadrisulphuretof potashso nearly resemble the quadrisulphuret of lime in their properties, as not to require any additional remarks.
Hydrosulphuret of potash.This combination, when duly proportioned, consists of 15 parts sulphuretted hydrogen, and 42 potash by weight, or one atom of each. It may be formed by directly uniting the two elements, or by decomposing hydrosulphuret of lime by carbonate of potash. Its properties agree with those of the other hydrosulphurets.
I have repeated most of the experiments on the sulphurization of potash with soda, and have not found anyone remarkable feature of distinction, besides those which arise from the weights of the atoms.
1.Sulphuretted carbonate of sodaconsists of 1 atom of carbonate of soda united to 1 of sulphur; or of 47 parts of the former and 14 of the latter.2.Trisulphuret of sodaconsists of 1 atom soda (28) and 3 of sulphur (42).3.Quadrisulphuret of sodaconsists of 1 atom soda (28) and 4 atoms of sulphur (56).Hydrosulphuret of soda.This compound consists of one atom ofeach of the elements, or 15 sulphuretted hydrogen, and 28 soda. In other respects it agrees with hydrosulphuret of potash.
1.Sulphuretted carbonate of sodaconsists of 1 atom of carbonate of soda united to 1 of sulphur; or of 47 parts of the former and 14 of the latter.
2.Trisulphuret of sodaconsists of 1 atom soda (28) and 3 of sulphur (42).
3.Quadrisulphuret of sodaconsists of 1 atom soda (28) and 4 atoms of sulphur (56).
Hydrosulphuret of soda.This compound consists of one atom ofeach of the elements, or 15 sulphuretted hydrogen, and 28 soda. In other respects it agrees with hydrosulphuret of potash.
The best way which I have found of procuring sulphuret of ammonia, is to treat quadrisulphuret of lime with the carbonate of ammonia as long as any precipitate takes place; the precipitate is sulphuretted carbonate of lime, 3 atoms of sulphur to 1 of carbonate of lime. The liquid is of a pale yellow, and contains ammonia and sulphur united in the ratio of 1 atom (of 6) to 1 of sulphur: it may therefore be denominated the protosulphuret of ammonia.
The carbonate of ammonia is best procured by heating the common subcarbonate of ammonia, first pulverized, in a temperature of 100° for half an hour, or exposing it for a few days to the atmosphere. What remains of the salt is almost without smell; it should consist of 19 parts acid, 6 ammonia, and 8 water nearly: the ammonia is usually however a small degree in excess.
Hydrosulphuret of ammonia.This compound may be formed in thedry state by combining the two gases of sulphuretted hydrogen and ammonia over mercury; it is of a white crystalline appearance, and very soluble in water, and forms a fuming liquor of a very pungent smell. It may also be obtained by passing sulphuretted hydrogen into a vessel containing liquid ammonia. I find about 110 or 120 measures of sulphuretted hydrogen require 100 of ammoniacal gas. Hence it is 1 atom of sulphuretted hydrogen (15), that unites to 1 of ammonia (6).
There exist at least two sulphurets of gold, the nature and proportions of which are easily ascertained; though several authors assert that no combinations of gold and sulphur are known; amongst these it is surprizing to find Proust: indeed most of the others have probably been led by his authority to adopt the opinion without examination. It is not very easy to account for his deception.
Obercampf, in the Annal. de Chimie, tom. 80. 1811, is the first author I have seen who distinctly maintains the existence of one or more sulphurets of gold, though it seems to have been admitted previously by Bucholz. The last author finds 82 gold unite to 18 sulphur, and the former 80 to 20 nearly.
Protosulphuret of gold.This compound is formed whenever a solution of muriate of gold is agitated with sulphuretted hydrogen gas, or with the same united to a base, as lime or alkali. A black or deep brown powder falls down by the addition of more gas, till the whole of the gold is precipitated. The oxide of gold loses one atom of oxygen, and receives one of sulphur in its place, whilst the hydrogen of the gas is carried off along with the oxygen of the oxide. The sulphuret dried and heated, burns with a blue flame, leaving the gold nearly pure. This compound consists, I find, of 81 gold and 19 sulphur per cent.; or 100 gold unite to 23 sulphur.
Trisulphuret of gold.This compound is obtained whenever quadrisulphuret of lime is gradually dropped into a solution of muriate of gold; it is a black powder, not quite so deep as the former. Care must be taken to saturate the excess of acid previously by lime water, to prevent any uncombined sulphur precipitating. Trisulphuret of gold being heated, burns with a blue flame, and leaves the gold nearly pure; it loses from 10 to 45 per cent. by the process. It is constituted of 1atom gold and 3 sulphur, or 60 gold and 42 sulphur, nearly; or 100 gold combine with 70 sulphur.
From several experiments I am led to conclude that each atom of oxide of gold takes 3 of sulphur, and parts with 1 of oxygen to the remaining sulphur; thus a trisulphuret of gold is formed, and an oxide of sulphur; the liquid, being afterwards treated with oxymuriate of lime, is found to require twice the oxygen of the gold for its saturation, when a corresponding portion of sulphuric acid may be precipitated by muriate of barytes.
Sulphur may be combined with platina in several ways, and probably in different proportions; but the combination is not so easily and elegantly effected as with many other metals, and hence some uncertainty still remains on the subject.
When a salt of platina is treated with sulphuret or hydrosulphuret of lime, or sulphuretted hydrogen water, the liquid slowly and gradually grows dark brown and finally black; after agitation and standing a few hours, the liquid is semitransparent, and a black flocculent precipitate appears at the bottom. Sometimes after violent agitation, the liquid on standing a few minutes becomes a transparent brown, butsoon grows turbid again. In the course of a few days, and by occasional agitation, the liquid finally becomes clear and nearly free from platina, and the precipitate may be collected on a filter and dried. This circumstance of slow and indolent precipitation cannot be prevented by any means I have found, such as saturating the excess of acid, &c.
Mr. Edmund Davy, in the 40thVol.of the Philos. Magazine, has given us the results of his experiments and observations on the sulphurets of platina, containing some useful and original information. He combines platina with sulphur by heating the ammonia-muriate of platina with sulphur; also by heating platina and sulphur in an exhausted tube; and by sending sulphuretted hydrogen gas or water into a solution of muriate of platina; this precipitate he calls hydrosulphuret of platina.
He has just noticed the precipitate formed by sulphuret of potash with muriate of platina, but gives no opinion as to the compound obtained this way. He determines three sulphurets, namely,
I have obtained the sulphuret of platina in five ways: 1st. By pouringsulphuret of lime solution by degrees into muriate of platina, and agitating the mixture well or till it grew black each time; after digesting for some days, repeated filtering, and drying, a black powder is obtained: 2. Instead of sulphuret, hydrosulphuret of lime was used; the precipitate was obtained under like circumstances: 3d. Sulphuretted hydrogen water was used, and the precipitate obtained in like manner: 4th. Ten grains of ammonia-muriate of platina were treated with sulphuretted hydrogen water; by continued agitation the yellow powder disappeared, the liquid looked uniformly black, and at length a precipitate was formed; by repeated filtration and addition of sulphuretted hydrogen water, the whole of the platina was thrown down, and the liquid remained colourless; but it is difficult to discover the exact quantity of sulphuretted hydrogen requisite for any weight of the ammonia-muriate from the tediousness of the operation; 6 grains of well dried black powder were obtained, besides perhaps 1 grain of loss on the filters: 5th. Ammonia-muriate of platina was heated in a covered crucible along with sulphur till it was judged that all the uncombined sulphur was sublimed or dissipated.
All these sulphurets appear to me to be the same when dried in a moderate heat. When exposed to a low red heat they yield water and sulphurous acid, and lose about ⅖ of their weight.
The subject however, requires further investigation. The sulphurets of platina appear of a complex nature, and the proportions of their elements are not yet determined with precision.
Silver combines with sulphur in two different proportions, and forms two sulphurets, both of them black or dark brown.
1.Protosulphuret of silver.This may be formed either by the dry or humid way: if thin lamina of silver be heated with sulphur, they combine and form this sulphuret; a higher degree of heat expels the sulphur again. It is formed too by passing sulphuretted hydrogen or a hydrosulphuret through a solution of silver in nitric or other acids. The atom of silver unites with that of sulphur, whilst the hydrogen unites with the oxygen. Of course this compound is composed of 90 silver, and 14 sulphur, and the atom weighs 104; or 100 silver unite with 15.5 sulphur. Klaproth finds 100 silver and 17.6 sulphur; Wenzel100 silver, and 14.7 sulphur; Berzelius 100 silver, and 14.9 sulphur; and Vauquelin 100 silver, and 14 sulphur.
Trisulphuret of silver.This compound is formed whenever neutral nitrate of silver is dropped into a solution of quadrisulphuret of lime or alkali. Mutual saturation seems to take place when eight atoms of nitrate meet with seven of quadrisulphuret. Trisulphuret of silver is constituted of 90 silver, and 42 sulphur; or of 100 silver, and 46.5 sulphur. Its colour is not so dark as that of the protosulphuret. The residuary liquid contains sulphurous acid, which is easily converted into sulphuric by the addition of a portion of lime; and the quantity of acid may then be determined by muriate of barytes.
Mercury combines readily with sulphur both in the dry and humid way, and that in several proportions, as under: namely,
1.Protosulphuret of mercury.This is most conveniently formed by passing sulphuretted hydrogen gas through a solution of the protonitrate of mercury, or by pouring hydrosulphuret of lime, &c. into the same solution. The protosulphuret falls down in the state of ablack powder. It consists of 167 mercury, and 14 sulphur; or of 100 mercury, and 8.4 sulphur. The theory of its formation is the same as that of silver.
2.Deutosulphuret of mercury.This is formed in the humid way whenever sulphuretted hydrogen or a hydrosulphuret in excess is mixed with the deutonitrate or deutomuriate of mercury (corrosive sublimate); a brown powder is precipitated which is the deutosulphuret. If the sulphuretted hydrogen be only one half what is sufficient to form the deutosulphuret, then we obtain no sulphuret, but instead of it a protonitrate or protomuriate, as was first intimated by Proust; I find however, the atom of sulphur adheres to the atom of salt, and that it is therefore a sulphuretted protonitrate or muriate, whilst 1 atom of oxygen unites with the hydrogen. The brown precipitate does not change to yellow, orange, and red, when left undisturbed for a few days, in my experience; though this is stated to have been observed by Mr. Accum. Notwithstanding the difference in colour, this deutosulphuret must be the same nearly as the cinnabar and vermillion of commerce, if Proust and others are right in their analysis of these articles. The combination of the elements of sulphur and mercury when intended toform cinnabar is made in the dry way by trituration, and a moderate heat: the compound, at first black, is afterwards sublimed by a duly regulated heat and becomes red. This compound must consist of 100 mercury and 17 sulphur nearly.
3.Quadrisulphuret of mercury.This compound is formed when a solution of protonitrate of mercury is treated with quadrisulphuret of lime, added by degrees till the clear liquid no longer gives a dark coloured precipitate. The oxygen of the mercurial salt unites, it should seem, to part of the sulphur, and forms sulphuric acid, whilst the rest of the sulphur unites to the mercury. This sulphuret is a black or dark brown powder, and when heated burns with a blue flame. It consists of 100 mercury, and 33 or 34 sulphur, as appears to me from the synthesis.
When the insoluble muriate of mercury (calomel), is triturated in liquid quadrisulphuret of lime, it is soon decomposed; quadrisulphuret of mercury is formed, with muriate of lime and sulphuric or sulphurous acid.
When the soluble muriate (corrosive sublimate), has quadrisulphuret of lime dropped into it by degrees; at first a yellowish white precipitate is obtained, which increases till it is one half saturated; after this,by continually adding more sulphuret, the precipitate grows darker, and ends in being quite black. It is at least as high as quadrisulphuret. Much sulphurous acid is found in the liquid.
The deutonitrate of mercury, produces a copious yellow precipitate with quadrisulphuret of lime. Exposed to the sun, it grows black in a few minutes on the light side, but continues yellow on the opposite side of the jar; at the same time, an effervescence and disengagement of oxygen gas are observed. Finally, the precipitate becomes the common quadrisulphuret, and the liquid contains sulphurous and sulphuric acids.
The recently precipitated and washed oxides of mercury act upon quadrisulphuret of lime. The black oxide seems to take 4 atoms of sulphur and part with its oxygen to another portion of sulphur; but the red oxide becomes light brown and retains the colour when dried. It seems to take the same sulphur as the black, but whether it retains any of the oxygen, I have not ascertained. The action is more slow than when the nitrates are used, and more quadrisulphuret of lime is expedient.
Mercury and sulphur combine in the dry way by trituration and by heat,forming a black powder; but the species of compounds and quantities of the ingredients combining in this mode, have not been ascertained.
Berzelius exposed 15 grains of palladium filings mixed with as much sulphur to a heat sufficient to expel the uncombined sulphur. The increase of weight was 28 per cent. upon the palladium: when exposed afresh with sulphur to heat, no addition was made to the weight.
Vauquelin heated 100 parts of the triple salt of palladium with an equal weight of sulphur, and obtained 52 parts of a blueish white sulphuret, very hard, and when broken exhibiting brilliant plates in its fracture. He had previously found that 100 salt contained 40 to 42 of metal: hence 100 metal combined with from 24 to 30 of sulphur. This agrees nearly with the above results of Berzelius. A very high degree of heat expels the sulphur and oxidizes the metal; but a more moderate heat leaves the palladium of a silver white colour and nearly pure. According to this the atom of protosulphuret of palladium must consist of 50 palladium, and 14 sulphur.
Vauquelin found that 4 parts of the ammonia-muriate of rhodium (containing 28 or 29 per cent. of metal) being mixed with an equal weight of sulphur, and heated, a blueish white button was obtained, weighing 1.4. Hence 100 metal seem to take 25 of sulphur; and allowing this to be the protosulphuret of rhodium, the atom must consist of one rhodium 56, and one sulphur 14, making the whole weight 70.
According to Vauquelin, 100 parts of the ammonia-muriate of iridium heated with as much sulphur, yield 60 parts of black powder resembling the other metallic sulphurets; but 100 parts of the salt were found to yield from 42 to 45 of metal. Now supposing the last number the most correct, it should seem that 3 parts iridium take 1 sulphur, or 100 take 33⅓. This being supposed the protosulphuret, the atom of iridium must be 42, and that of the sulphuret 56.
It is as yet unknown whether any combination of sulphur and osmium exists.
Copper readily unites with sulphur both in the dry and humid way. When 3 parts of copper filings are mixed with 1 part of sulphur, and heat applied, a brilliant combustion ensues, which indicates the union of the two bodies. Copper leaf burns in the fumes of sulphur, as Berzelius has observed, with great brilliancy.
The protosulphuret of copper obtained by these similar methods, when pulverized, is black or dark coloured; it has been analyzed by various authors, who nearly agree in their results. Proust finds 100 copper unite with 28 sulphur; Wenzel, 100 copper and 25 sulphur; Vauquelin, 100 copper and 27 sulphur; and Berzelius 100 copper and 25 sulphur.
If the atom of copper be 56, and that of sulphur 14, the atom of protosulphuret of copper will be 70; which gives just 100 copper and 25 sulphur.
The protosulphuret may also be formed in the humid way, by sending sulphuretted hydrogen gas or a hydrosulphuret into a solution of protomuriate of copper, or amongst the recently precipitated protoxide of copper.
Deutosulphuret of copper.This compound is formed wheneversulphuretted hydrogen gas or a hydrosulphuret is sent into a solution of salt containing the deutoxide, or into the deutoxide just precipitated from any acid. It is a dark brown powder not differing much in appearance from the protosulphuret. It consists of 100 copper and 50 sulphur; the weight of the atom is 84.
Quadrisulphuret of copper.This compound is formed by mixing quadrisulphuret of lime with a salt of the deutoxide of copper, and diluting the solution. A light brown precipitate falls immediately, which is the quadrisulphuret of copper. It burns with a blue flame, and leaves the protosulphuret. The atom consists of 56 copper and 56 sulphur, or weighs 112; and hence the sulphuret consists of equal parts copper and sulphur.
The blue hydrate of copper recently precipitated from a salt of copper and washed, acts upon quadrisulphuret of lime; the results, according to my experience, is quadrisulphuret of copper, and the oxygen unites with the sulphur remaining in the liquor.
Sulphur may be united to iron either by the dry or humid way, and that in various proportions.
Protosulphuret of iron.This compound may be formed by passing a hydrosulphuret into a solution of the green oxide in any acid. It is a black powder. It may also be formed by rubbing a highly heated bar of iron with a roll of sulphur; the two unite in a fluid form and soon congeal into a brownish black mass. It is too a natural production, though not very common; excellent analyses of it, as well as of the common pyrites, were some time ago given by Mr. Hatchett. (See Nicholson’s Journ.Vol.10.) The protosulphuret is magnetic in a considerable degree; it is soluble in acids, and yields sulphuretted hydrogen. It is proper to notice that the sulphuret of iron is not precipitated from solutions by sulphuretted hydrogen simply or without a base. According to Mr. Hatchett this sulphuret consists of 100 iron, and 57 sulphur, which corresponds with 1 atom iron 25, and 1 of sulphur, 14, nearly.
Deutosulphuret of iron.This is a natural production frequently met with, and in various forms; it is called pyrites, or iron pyrites; it is a yellowish mineral and often appears when broken, of a radiated texture, but sometimes it is crystallized in cubes or dodecahedrons. Acids have little effect upon it, except the nitric, which when dilutedattacks both the sulphur and iron; much nitrous gas is produced, the iron is dissolved, and the sulphur chiefly converted into sulphuric acid. This sulphuret consists, according to Proust, of 100 iron, and 90 sulphur, and with this Bucholz recently agrees (Nichols. 27—356); but Hatchett makes it 100 iron, and 112 sulphur. From an experiment of my own on the radiated pyrites, I found nearly equal parts of iron and sulphur. One atom of iron (25,) and two of sulphur (28,) would give 100 to 112; but if the atom of sulphur be only 13, it gives 100 iron to 104 sulphur. Mr. Hatchett unfortunately calculating the proportions of the ingredientsin100 sulphuret, instead ofon100 iron, did not notice that the sulphur in the common pyrites is just double of that in the magnetic pyrites.
Quinsulphuret of iron.This combination consisting of 5 atoms of sulphur with 1 of iron, is formed by mixing a solution of green sulphate of iron with quadrisulphuret of lime in due proportion. I found 50 measures sulphate 1.168 saturate 310 of 1.05 sulphuret diluted so as to become 6 oz.; this yielded 14 grs. dried sulphuret of iron = 3.6 iron, known to be in the sulphate, and 10.4 sulphur; the liquid contained 2+ sulphur combined with the lime and oxygen of the oxide;for it took 2.3 oxygen by means of oxymuriate of lime to convert the sulphur into sulphuric acid together with 1+ from the oxide, making 3+ oxygen, which unites to 2+ sulphur to constitute 5+ sulphuric acid; and this quantity of acid was found to exist by muriate of barytes together with five more brought in by the sulphate of iron. This sulphuret is a yellowish brown powder; it readily exhales sulphur by heat and is reduced to the protosulphuret; but in the open air it burns with a blue flame and leaves the protosulphuret partially, as I apprehend, oxidized. The theory of the formation of quinsulphuret seems to be this: 3 atoms of quadrisulphuret of lime are requisite to saturate 2 of sulphate of iron; the 2 atoms of sulphuric acid seize 2 of lime, three fourths of the sulphur unite to the iron, and one fourth to its oxygen, forming 2 atoms of oxide of sulphur, which attack the 3d atom of sulphuret and decompose it, giving its sulphur to the iron, and neutralizing the lime (for the liquid is found neutral). In this way 10 atoms of sulphur are united to 2 of iron, and 2 of sulphur to 2 of oxygen, with one of lime, which last compound remains in solution, and the oxide of sulphur may be converted into sulphuric acid immediately by the application of oxymuriate of lime.
It is remarkable that neither the green nor the yellow oxides of iron, even when recently precipitated and not dried, seems capable of decomposing quadrisulphuret of lime.
It is probable that trisulphuret and quadrisulphuret of iron may be formed; but I have not ascertained the truth of this opinion.
Protosulphuret.According to Proust, nickel unites to sulphur by heat, so that 100 take 46 or 48; the sulphuret is of the colour of common pyrites. (Journ. de Physique, 63 and 80). According to Mr. Ed. Davy 100 nickel take 54 sulphur. By saturating a solution of nitrate of nickel with hydrosulphuret of lime I obtained 40 grains from 33 protoxide or 26 metal. This was evidently the protosulphuret; it was a fine black powder, and consists of 100 metal and 54 sulphur.
Quinsulphuret.This compound may be obtained from nitrate of nickel and quadrisulphuret of lime, in the same manner as that of iron. It is a deep black powder, and consists of 100 nickel, and 215 sulphur. By exposure to heat, the greatest part of the sulphur burns off, and the rest may be expelled by an increase of temperature.
Probably intermediate sulphurets may be formed; but I have not pursued the investigation.
Sulphur and tin unite both in the dry and humid way, and in various proportions.
Protosulphuret.This may be readily formed in the dry way as follows; let 100 grains of tin be fused in a small iron ladle and heated to 6 or 8 hundred degrees Fahrenheit; let then small pieces of sulphur of 10 or 20 grains be successively dropped into the fused metal: a copious blue flame will instantly arise each time, and a glowing heat will take place, when the sulphur and tin are in contact; as soon as this ceases, another fragment of sulphur must be dropped in, and this two or three times repeated, heating it at last to a perfect red; the mass may then be taken out and pounded in a mortar; a great part of it will be a pulverulent powder, but some portions of malleable metal will still be mixed with it, which may be separated by a sieve. This must be again heated and treated with sulphur as before, and the whole mass will be converted to a sulphuret. I find that 100 parts of tin become in this way 127 grains; which is the due proportion of 52 tin and 14 sulphur, so that no loss of tin is sustained by the processwhen duly managed. According to Wenzel, 100 tin take 18 sulphur; Bergman, 25; Pelletier, 15 to 20; Proust, 20; but Dr. John Davy and Berzelius find nearly 27 as above stated, and I have no doubt it is near the truth.
The protosulphuret of tin is a dark grey shining powder, with a streak like molybdena or plumbago; it is not much different in colour and appearance from native sulphuret of antimony, only less blue. It is soluble in muriatic acid by heat, and yields sulphuretted hydrogen and protomuriate of tin.
Deutosulphuret.This compound is better known than the former: it may be formed in various ways; one is by heating a mixture of deutoxide of tin and sulphur in a retort almost to a red heat; sulphur sublimes and sulphurous acid is disengaged, and there remains a yellow, light shining, flaky mass at the bottom of the retort which is the sulphuret. It was formerly calledaurum musivumor mosaic gold. Pelletier and Proust were of opinion that this product is a sulphuretted oxide of tin; but Dr. John Davy and Berzelius have rendered it more probable that it is a true deutosulphuret, consisting of 100 tin and 54 sulphur. It is insoluble in muriatic or nitric acid, but slowly soluble by the compound of the two acids; it is also solublein potash by heat. By exposing it to a bright red heat, it burns with a blue flame and leaves a yellowish powder which dues not seem to differ much from protosulphuret.
Berzelius distilled a mixture of protosulphuret and sulphur at a low red heat, and obtained a mass of a yellow grey colour and metallic lustre, which consisted of 100 tin, and 14 sulphur, which is just the mean sulphur between the other two. This would seem to indicate that a compound of the two sulphurets, 1 atom to 1, is capable of being formed.
Hydrosulphuret of tinminor. This compound is formed according to Proust, when sulphuretted hydrogen, or an alkaline or earthy hydrosulphuret is passed into a solution of protomuriate of tin. It is of a brown or dark coffee colour when precipitated, and black when dried. By heat it yields water and protosulphuret. From some experiments I am inclined to believe, that it is formed of 1 atom protosulphuret and 1 of water: or, which is the same, 1 atom protoxide of tin and 1 of sulphuretted hydrogen. If this be right it may be said to be a compound of 100 tin, 27 sulphur and 15 water.
Hydrosulphuret of tinmajor. This name is given by Proust to the yellow compound thrown down by sulphuretted hydrogen or by hydrosulphurets from solutions of the deutoxide of tin. When dried moderately, the precipitate is of a dull yellow colour, and vitreous fracture, but I find it is almost black, dried in a heat of 150° or upwards. By moderate heat it yields water, sulphurous acid, sulphur, and the residue is deutosulphuret of tin according to Proust. I heated 4 parts of the above previously dried so as to become a black vitreous powder; it burned feebly with a blue flame, and after being made moderately red, left nearly 3 parts exactly resembling the artificial protosulphuret. I believe the dried precipitate will be found to be constituted of 1 atom tin, 2 sulphur and 1 water; that is, 100 tin, 54 sulphur and 15 water = 169 by weight; and that it loses 27 sulphur and 15 water by a red heat, which reduces the weight just one fourth.
Quinsulphuret of tin.This is obtained in the humid way, by first precipitating the oxide, and then putting quadrisulphuret of lime or potash to the liquid containing the precipitate, till the liquid after agitation and subsidence of the precipitate continues of a yellowish colour. I found that 31 measures of protomuriate of tin of1.377 = 7 grains acid, 7.5 tin and 1 oxygen, precipitated by 10 oz. lime water, required 450 measures of 1.40 sulphuret of lime, containing 16 sulphur and 7.2 lime, for their saturation. The residuary liquid was nearly colourless, and the precipitate dried in an oven of 100° or more, for 10 hours, weighed 17 grains besides loss in the operation. It was a yellow, vitreous mass, and when pulverized and heated, burned with a blue flame, and lost 40 per cent. in weight; the residue was a yellow grey colour, and seemed to be like the intermediate sulphuret of Berzelius; it would not give sulphuretted hydrogen by hot muriatic acid. Now if 52 (1 atom tin) ∶ 70 (5 atoms sulphur) ∷ 7.5 tin ∶ 10+ sulphur; hence the sulphuret should have weighed 17.5 grains, which was the observed weight, allowing ½ grain for loss. According to this, 100 tin combine with 135 sulphur, and when burnt, the 235 are reduced to 140, the weight observed by Berzelius in the instance alluded to. The liquid required 5 grains of oxygen from oxymuriate of lime, to convert the sulphur into sulphuric acid, and the weight of this acid, found by muriate of barytes, was 11 grains, indicating 4.4 sulphur. It may be observed that the 4.4 grains, and 10 grains, do not make up the whole(16) of the sulphuret of lime; but the reason I apprehend was, that the quadrisulphuret was old, and did not contain the full share of sulphur, it being usual for a small part to fall by time.
The deutomuriate of tin, precipitating the oxide in like manner, yielded a sulphuret rather lighter yellow than the above; about 10 tin gave 25 grains of sulphuret dried in a temperature of 80 to 100°. This compound still contained water, and I suspect it will be found constituted of 1 atom tin, 5 sulphur, and 2 water.
Lead combines with sulphur in various proportions, some of which are natural productions of great purity.
Protosulphuret.This is a natural production which is called galena; it is of lead grey colour and metallic appearance, and is found both in masses and crystallized; its sp. gr. is about 7.5. It may be formed artificially by heating lead or its oxide with sulphur; also by treating a solution of lead with sulphuretted hydrogen or with a hydrosulphuret. Authors are well agreed as to the proportions of the ingredients; 100 lead combine with from 15 to 16 sulphur. That is, 90 lead with 14 sulphur; or 1 atom of lead with 1 of sulphur.
Deutosulphuret.Dr. Thomson mentions a natural production or species of galena which contains twice the quantity of sulphur of that above. I have reason to believe that this compound is easily formed in the humid way, by treating the precipitated oxide with the due quantity of quadrisulphuret of lime.
Trisulphuretandquadrisulphuret. These compounds, I find, may be formed by means of quadrisulphuret of lime or potash. When a solution of any salt of lead or the recently precipitated and moist oxide, is treated with the requisite quantity of quadrisulphuret of lime, a combination consisting of 1 atom of lead and 3 of sulphur is formed. It is a black powder not differing much in appearance from the protosulphuret; it is lighter and more spongy. It consists of 100 lead and 46 or 47 sulphur. The due proportions of the elements to form the above compound are, lead 100 parts in solution, and sulphur, 62 parts; ¼ of the sulphur is retained by the lime, and may be converted into sulphuric acid instantly by the addition of as much oxymuriate of lime as contains oxygen equal in weight to the sulphur, as it has already as much oxygen as converts it into sulphurous oxide, derived from the oxide of lead.
Quadrisulphuret of lead is to be obtained in the same way; only we must have an excess of the sulphuret of lime, or more than 80 sulphur for 100 lead in solution, as ⅕ part of the sulphur at least is retained by the lime. The quadrisulphuret is a black powder like the others; it burns with a blue flame and loses nearly 40 per cent., the residue being still black. It consists of 100 lead and 62 sulphur.
I have not ascertained whether any higher sulphuret of lead is capable of being formed this way.
It has been already noticed (page 109), that a beautiful white, silvery sulphuretted sulphite of lead is formed and gradually precipitated, when nitrate of lead is dropped into a solution where as much black quadrisulphuret of lead has been just thrown down as the sulphuret of lime can form.
Zinc and sulphur are scarcely to be united directly by heat; but by heating the oxide of zinc and sulphur together, a combination is effected; part of the sulphur carries off the oxygen in sulphurous acid, and part combines with the zinc. Mineralogists give the name ofblendeto a mineral which is chiefly the protosulphuret of zinc: its colour is yellowish, brown, or black almost like galena: its specific gravity is usually 3.9 or 4.
Protosulphuret.The above artificial compound, or the mineral, may be taken as examples of the union of 1 atom zinc and 1 sulphur. But the most correct and convenient way of forming it for the purpose of chemical investigation is, to drop a given portion of some salt of zinc into a dilute hydrosulphuret. A white precipitate falls, which when dried becomes a dark cream colour. It is found to consist of 2 parts zinc and 1 of sulphur nearly; that is, of 29 parts zinc and 14 sulphur.
Deutosulphuret,trisulphuret, &c. of zinc. These combinations may be made, up to the 5th orquinsulphuret, in the humid way by quadrisulphuret of lime, &c. The oxide may be first precipitated by lime water, or not, as we please, and then treated with quadrisulphuret according to the degree of sulphuration required. I found 100 measures of 1.29 nitrate of zinc with 2500 of 1.026 sulphuret of lime yield 40 grs. dry sulphuret zinc, of a yellowish white colour; the liquid was found to retain 13 or 14 grains of sulphur, byconverting it into sulphuric acid by means of oxymuriate of lime. The nitrate contained 11½ zinc and 2.8 oxygen; so that about 28 sulphur had combined with the zinc, and about 14 remained in solution, or ⅓ of the whole, as has been already explained. By proportion, if 11½ ∶ 28 ∷ 29 ∶ 70; or 1 atom of zinc (29) combines with 5 atoms of sulphur (70). The intermediate combinations I have not particularly examined; they do not differ much in appearance from the one just described; they burn blue and are reduced by it to the protosulphuret; and they give sulphuretted hydrogen by muriatic acid.
According to Davy and Gay Lussac, potassium and sodium unite with sulphur by heat with vivid combustion. The compounds appear to be protosulphurets, that of potash being nearly as 35 potassium to 14 sulphur, and that of sodium as 21 sodium to 14 sulphur. When potassium and sodium are heated along with sulphuretted hydrogen, an union likewise takes place; two atoms of gas unite to one of the metals, except that 1 atom of hydrogen is liberated, corresponding of course inquantity to that liberated by treating them with water. When the compound thus formed is treated with muriatic or sulphuric acid, the same quantity of sulphuretted hydrogen nearly is liberated that was originally combined. So that the compound may be regarded as sulphuretted hydrogen united to the protosulphurets. The colour of these sulphurets varies from grey to yellow or reddish.
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 sulphurettedhydrogen 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 forsome 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.
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 muriaticacid 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,trisulphurettedandquadrisulphuretted 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 havebeen 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.