27 VI.-On some Native Combinations of Oxide of Mercury with Oxide of Antimony. BY FREDERICK FIELD. M. Do M EY IC 0,in an extended memoir upon the minerals of Chili pinblished in the Annales des Mines 4 series vol. vi p. 183 mentions a red piilverulent substance found in small quantities in the cavities and upon the sides of grey uaercury ore. This snb-stance it is said forms an impalpable powder is scarcely attacked by hydrochloric acid but dissolves easily in nitric acid without disen- gagement of sulphiiretted hydrogen. Dana in the third edition of his Mineralogy page 534 mentions the mineral ammiolite from appov (vermilion) discovered by Domeyko the same doubt- less as that described in the Annales desMines and having the following composition :- Antimonious acid (SbO,) .12.50 Oxide of mercury . 14-00 Sesquioxide of iron . . 22.30 Silica . . 26.50 Water and loss . . 24.70 1oo*oo I have lately obtained very fine specimens of a red mercurial mineral differing very much in constitution from the above apparently of some interest to mineralogical science as the mercury exists to a great extent in an oxidized coiidition associated with teroxide of antimony. The specimens alluded to were obtained from the surface of a hill near Tambillos about 9 leagues east of Coquimbo in a porphyritic formation. The mineral however itself being immediately associated with hydrated oxide of iron and car-bonate oi lime I caused the min to be csplored to the depth of about 20 yards and obtained a considerable quantity of ore running in small veins along the lode and occurring at intervals in rounded masses and nodules.The mineral which had a bright red colouir was occasionally very much mixed with many others of 3' PJELD ON CUMBINATLONS OF a wry opposite clcscription. In one specimen alone weighing oiily a fcm ounces tlic following merc observed :-lo A small vein of a ncm variety of mercurial fahlore of a dark crimson colour highly lustrous and metallic coritaining inercury copper antimony arsenic zinc and sulphixr 2" A scarlet wassivc substance consisting of oxide of mercury oside of copper oxide of antimony sulpliide of antimony sulpliidc of mercury arid small quantities of osiclc of iron and mater. Crystals of ospcliloride of copper (atacamite).4P Green carbonate of copper. 5O Blue carbonate of copper. 6' Black silicate of manganese and copper 7O Hydrated oxide of iron. The five latter substances were scattered about tlie mineral and could be more or less separated from the red mercurial ore by the hammer It may be imagined that it wasa matter of extreme difficulty to obtain a sufficient quantity of pure substance for the purpose of qaantitstive analysis but having more than 1201bs. of specimens at my command 1 was enabled to select some very fine samples. Great doubt still exists regarding the copper as to whether it forms an esseiitial part of the mercury ore or is only in close mechanical coniiection with it. The following researches may tend to clear up in some degree certain points which have hitherto been rather obscnre although froin thc earthy nature of the riiiicral and the entire absence of crystallisation there is still room for doubts as to its true forinula- 100 graiiis of the earthy red mass freed as much as possible from all foreign ingredients gave as a mean of three analyses the following numbers :-Copper .16.66 Mercury . 27.52 Aiitimony . 10.21 Chlorine . 050 Sesquioxidc of iroii 2.18 Carbonic acid . 2.10 Water . 5.65 Sulphur . 4.01 Silica . . 23.38 On examining the pulverised mineral with a lens bright green particles were observed among the scarlet powder consisting partly of carbonate and partly o€ oxychloride of copper. No mechanicd means could separate these substances and the above analysis clearly shows that at least two well-known mincrals are associated with the one under examination.The sulpliur exists partly in combination with the antimony and partly with the mercury as the prolonged action of hydrocldoric acid dissolves the whole of the former metal as well as all tlie copper leaving small particles of sulphide of mercury undissolvecl and disengaging sulphuretted hydrogen from the decomposition of the sulphide of antimony. The loss in thc analysis is chiefly due to oxygm and by combining that element with the metals we have the fo1lo.c~ ing composition of the mixture :- Carbonate of copper (CuO.CuO,CO,) 9.73 Oxychloride of copper (3Cu0,CuCl) . 2.62 Oxide of copper .ll*CO Teroxide of antimony . . 6.244 Tersulphide of antimony . . 7.01 Oxide of mercury . . 1G.22 Sulphide of mercury . . . 14.50 Sesquioside of iron . . 2.12 Water . . . 5.65 Silica . 2,3*38 98.47 It occurred to me that perhsps the action of weak acids might remove many extraneous matters apparently not imme-diately connected with the mineral aid also throw some additional light upon its constitution. Action of Hydrochloric Acid. When the scarlet powder is digested with warm dilute hydro- chloric acid slight evolution of sulphuretted hydrogen takes place and the whole of the copper and part of the mercury and antimony are dissolved; the residue which has a light pinkish colour consists of silica mingled with particles of undecomposed ore.Strong boil -ing hydrochloric acid attacks it poweriully disengaging sulphu- retted hydrogen and dissolving the whole of the copper and antimony and the greater part of the mercury. The residue Elas still a light red coloiir aid contains about 2 per cent. of mlphur the rernain- no FIELD ON COHRINATTONR OF der of that element having been eliminated as hydrosulpliuric acid. The addition of iodide of potassium to the hydrocliloric acid solution precipitates iodide of mercury which is redissolved by an excess of thc precipitant; but no free iodine is evolved proving that the antimony exists as SbO and not SbO or SbO,. A mixture of hydrochloric acid and clilorate of potash attacks the mineral with considerable energy and if it is in a very attenu- ated state decomposes it completely after some time.Aqua regin exerts a similar action. Ordinary nitric acid dissolves all the copper but scarcely aity antimony or mercury. The powder assumes a brighter scarlet colour from the abstraction of the green particles of carbonate and oxychloride of copper which diminish its brilliancy. The strongest fuming nitric acid affects it but little; like the otlicr reagents above mentioned it abstracts all the copper. IIcatcd in a glass tubc the mineral loses water even beyond 212",but rcgairis its original weiglit after a few hours exposure to the air. From the above reaction it would appear that the mercury and antimony are in a peculiar state of combination forming a definite compound in which the copper takes no part.Although oxide of iiicrcury is rery soluble in nitric acid little or none is dissolved uhen it is in association with teroxide of antimony although thc wliole of the copper is imniecliately extracted wen when the acid is extremely dilute. Acetic acid also when gently warmed dis- solves the whole of the copper after two or three days while the red mineral augments in brilliancy of colour and falls to the bottom. These facts lead me to believe that the copper is only mechanically mingled with the mercurial compound more espe- cially as very few specimens contain the same amount of cupreous inatters'; but after digesting the mass in dilute nitric acid the other elemeuts are found in certain relative proportious.This is still more probable from the fact that in the mineral as it is talcen froin the earth various shades of red from scarlet to crimson are observed depending evidently upon the greater or less amount 01 copper contained. After digestion in nitric acid the residue froni nearly all samples has the same colour. After very fine division a quantity of the mineral was digested in dilute nitric acid for some days. The solution had a dark blue colour and contained much copper and some iron but scarcely traces of sulphur mercury or antimony. There was also a small quantity of arsenic. OXIDE OF MERCURY WITH OXIDE OF ANTIMONY The powder when thoroughly dry was nnalysed and yielded :-Mercury . . 34.42 Antimony . . 14.21 Sulphur . . 5.43 Sesquioxide of iron .. 2.68 Water . 4.46 Silica . 35.50 96-70 Another sample freer from silica gave :-Mercury . . 37.94 Antimony . . 15.26 Sulphur . . 5-98 Sesquioxide of iron . . 2-94 Water . . 4.98 Silica . 29.78 96-88 By dividing the sulphur equally between the mercury and antimony making the former a simple and the latter a tersulphide and oxidising the remainder of each metal we obtain :-No. 1. No. 2. Oxide of mercury . . 15-16 20.79 Sulphide of mercury . 20.31 21.68 Teroxide of antimony 8.92 9.3% Tersulphide of antim ony . 9.48 10.46 Sesquioxide of iron . . 2.68 2.94 Water . . 4-46 4.98 Silica . . 35.30 29.78 99.51 99.97 Considering the silica and oxide of iron as accidental irn pnrities we have after deducting the water :-No.1. No. 2. Oxide of mercury . 31.77 33.36 Sulphide of mercury . 35.53 34-83 Teroxide of antimony . 15-61 14-92 Tersulphide of antimony 16.52 16.77 -._I 99.43 99-88 FIELD ON COMBINATIONS OF The mean of wlricli would be as undcr :-Oxide of mcrcury . . . 32-56 Sulphide of mercury . . 35.18 Teroxide of aiitirnoiiy . . . 15.27 Tersulphide of antimony . . 16.64 99.65 Little doubt can exist I imagine that this red mineral is the product of a partial oxiilatioii of a natural compound of sulphur antimony mercury and copper and that the oxide of the last metal is either only mechanically mixed or in very feeble com- bination with the sulphidcs and oxides of the other metals. The sulphide of mercuiry acts doubtless as a sulphur-base the sulphide of antimony being the sulphur-acid mhi4st the oxide of mercury plays the same part witli regard to the teroxide of antimony which in this instance also acts as an acid.The mineral may then be considered as a tribasic siilphantimonite of mercury combined witli tribasic aiitimonite of the same metal (3HgS,SbS,) + (3IlgO,SbO,) which requires the following numbers :-Oxide of merciiry . . 32.93 Sulphide of mercury . . . . 35.3'1 Teroxide of antimony . . 77-07 Tersulphide of aiitiniony . 1606.3 10000 The formula of the mineral may also possibly be the following 3(2HgO,€IgS) + (2SbS,,SbO,) which lias exactly the sainc pcrcentage composition as thc former and may be regarded as an oxysulphide of mercury couplcd witli an oxysulphide of antimony.The compound BSbS,,SbO is already known but 2HgO,HgS has not yet I believe been described. On the Sepumtion of Mercu~y fiona Antimony. Sulphide of mercury is perfectly soluble iu the sulpliides of potas-sium and sodium but scarcely so in the sulphides of ammonium. Weber tells us that in the presence of free alkali certain double compounds are formed tritli the alkaline sulphides and sulphides of mcrcurp. Free alkali however is not neccsswg. Crystalliserl OXIDE OF MERCURY WI TIE OXIDE OF ANTIMONY. monosulphide of sodium when in solution at once dissolves sulphide of mercury; when a solution of corrosire sublimate is dropped into one of the alkaline sulphates the black precipitate is immediately dissolved and the liquid remains perfectly colourless and clear.When this solution is exposed to the air for some days hydrosulphite of soda is formed and sulphide of mercury separates as a crystalline deposit. When the compound is placed in stoppered bottles it remains many months without decomposition. The sulphide of mercury evidently acts as an acid and may with propriety be termed sulphydrargic and its salts sulphydrargates. When a solution of arsenite or arseniate of an alkali is poured into sulphydrargate of sodium sulphide of mercury being the weaker acid is displaced and sulpharsenite or sulpliarseniate of the alkali is formed Although acting as a base towards sulphide of antimony it acts as an acid towards the alkaline siilphides; and thus if the red mineral for example be digested in a solution of sulphide of sodium it is nearly all dissolved silica sulphide of iron with traces of sulphide of mercury forming the residue.It may be imagined that in the first of the analyses mentioned great practical difficulties were experienced in the separation of the antimony from the copper and mercury inasmuch as by the application of sulphide of ammonium considerable quantities of copper were dissolved and by employing either of the other alkaline sulphides nearly all the mercury was dissolved with the antimony. A very perfect separation of the sul-phide of antimony from mercury appears to be obtained by digesting these compounds in moderately strong hydrochloric acid when all the sulphide of antimony is dissolved but not a trace of sulphide of mercury.A distilling apparatus is necessary as chloride of antimony is slightly volatile in the vapour of hydrochloric acid. If the two sulphides are digested in a retort connected with a condenser the distilled liquid should be added to that separated by filtration from the sulphide of mercury when the digestion is completed and the liquid after great dilution precipitated by sulphuretted hydrogen. Even when copper is not present it is difficult to get rid of the antimony from the mercury by means of sulphide of ammonium and with this reagent traces of sulphide of mercury are dissolved. In order to prove the accuracy of the separation by means of hydrochloric acid the following experiments were tried :-1.00 gr.tersulyhide of antimony was dissolved in hydrochloric VOL. XII. D FIELD ON ~OMI~~NI\’IIO~’S 34 OF ;I(;icl and 12.00 of protochloride of mercury added. The metals were precipitated by hydrosulphuric acid and the sulphides digested in strong warm hydrochloric acid the vapour of which was condensed and added to the filtrate. After dilution with water the liquid was saturated with sulphuretted hydrogen and at the expiration of twenty-four hours the sulphide of antimony collected on a tared filter dried and weighed. The sulphide of mercury was washed collected and estimated. Taken. Found. SbS . 1.00 = 0.71 Sb. SbS . . 0*96 = 0.685 HgCl . . l2*00= 8-82Hg. HgS . . 10.41 = 8.973 9.53 9.658 Another experiment in which I.00gr.HgC1. and 12 grs. Sb.S were taken gave :- Taken. Found. 1.00 Hg.C1. = 0735 0.856 HS = 0.7‘37’ 12-00Sb.S = 8.571 11.890 SbS = 8.493 -7 9-306 9.230 As the red mineral is perfectly decomposed by acids only when in the finest state of division a very convenient method is to digest the powder in a strong solution of sulphide of sodium. The residue consists of silica with sulphide of iron and traces of sulphide of mercury while the filtrate contains the whole of the antimony and the greater part of the mercury. If the residue is now treated with hydrochloric acid and chlorate of potash the silica remains perfectly white and the mercury may be precipitated by sulphuretted hydrogen. The small quantity of sulphide of mercury is added to the sulphide of sodium solution acid is introduced and the whole boiled until disengagement of sul-phnretted hydrogen ceases.The sulphide of mercury together with uncombined sulphur is washed upon a tared filter dried at 212O and weighed. A portion is taken and the sulphur is estimated in the usual manner from which the weight of mercury is calculated from the whole amount of precipitate. The antimony is pre-* The late experiments of Schneider confirmed by Rose have shown that the equivalent of antimony as stated by Berzelius is far too high. Berzelius gives it as 129 or 64.5. Schneider as 120 and Rose as 120.60. I have adopted 125. OXIDE OF MERCURY WITH OXIDE OF ANTIMONY. cipitated from the diluted solution by sulphuretted hydrogen and the sulphur also estimated the antimony being calculated as loss.Although apparently differing in many essential points from the red mercurial ore of M. Domeyko more especially with regard to the action exerted upon it by hydrochloric and nitric acids it is doubtless only a variety of the same mineral derived from the oxidation of mercurial fahlore. I have thought it as well there- fore not to designate it by any new appellation but at present at least to call it arnmiolite a name given to it by its distinguished discoverer.