BfUIR ON CERTAIN BISMUTE CONPOUNDS. II.-On Certain Bismuth Conqmds. Part 111. By M. 11.PATTISON MUIR,F.R.S.E. Assistant Lecturer on Chemistry The Om-ens College. 1. INa former paper (this Journal [2],xv 12) I have described four chromates of bismuth the production of one or other of which appears to be conditioned principally by the quantity of acid or alkali present by the temperature and by the time during which the action is main- tained. To one of the chromatm described in the above quoted paper I assigned the formula Bi2034Cr03.H,0or (BiO),Cr40,,H20. I have now to describe a new chromate obtained from this salt. 2. This salt was itself prepared from another chromate by treatment Trith strong nitric acid heating until the whole or almost the whole of the acid was expelled washing with water and drying.If however a considerable quantity of acid be allowed to remain in the salt and it be then repeatedly boiled with water a light orange-coloured salt is obtained the analysis of which dried at loo" gave the following results :-(a.) 0.639 gram gave 0.566 gram Bi,Os = 0.508 gram Bi. (b.) 0.3445 , 0.227 , . = 0.2037 , , (c.) 0.839 , 0.20 , Cr,03 = 0.150 , Cr. (d.) 0.3445 , 0.084 , , = 0.0575 , , Poulla. Calculated for A Y SBi,03.7CrOa. I. 11. 111. IV. Mean. Bismnth.. 59.85 60.55 59.13% -59-84 Chromium 17.35 -17.88 16.69 17-28 Tlie formula given above might be written (Bi,O3.5CrO3) 2{ (BiO) MUIR ON CERTAIN BISMUTH COMPOUNDS. CrO,) as if the salt were a compound of bisnzutl~ylpentacl~romate,and normal bismuthy1 chromatem 3.This chromate is of a light orange colour ; it is insoluble in water but is easily dissolved by dilute mineral acids especially by hydro- chloric acid. Strong hydrochloric acid dissolves it without heating with evolution of chlorine and formation of a very dark claret-coloured liquid. Cold caustic potash partially dissolves this chromate and partially converts it into a loose bulky light-yellow salt ; boiling potash converts it for the most part into a heavy dark brown-red salt' which is insoluble in water ; a portion of the chromate is at the same time dissolved with the formation of a greenish-yellow liquid. When heated this chromate becomes much darker in colour but the original shade is almost completely restored on cooling.4,In Part I1 of these researches I have described a chromate of bismuth having the formula Bi,O3.2CrO3 and prepared by boiling the precipitate obtained in a nearly iieutral solution of bismnthic nitrate by means of potassium chromate with an excess of the precipitant and a few drops of nitric acid. In attempting to prepare a fresh quantity of this salt (I had already prepared it on several distinct occasions) I found that the yellow colour of the original precipitate did not entirely give place to red even after very prolonged heating but that a heavy reddish-orange-colonred salt was obtained. On account of the great density of this salt it was extremely difficult to maintain the liquid in active ebullition hence for the greater part of the time during which the action was proceeding the teniperature of the liquid did not attain to 100".It is very probable-as already pointed out- that temperature materially conditions the formation of these chromates of bismuth. The dense salt was washed until perfectly free from acid dried at lOO" and analysed :-(a.) 0,4135 gram gave 0.275 gram Bi,03 = 0 2466 gram Bi. (b.) 0'509.5 , 0.336 , , = 0.3015 , , (c.) 0.4135 , 0.096 , Crz03= 0.0657 , Cr. (d.) 0.5095 , 0.120 , , = 0.0822 , , (e.) 1.023 gram heated gently over the Bunsen lamp lost 0.0315 gram. Found. Calculated for 5Bi,0311Cr036H20. 'I. 11. 111. A IT. 7. Mean. \ Bismuth . . 59.15 59.63 59-1.7 --59.40 Chromium. 16.17 -15.89 16.13 -16.01 Water . .. . 3.04 --3.08 3-08 The formula given above might be written 2(Biz03.4Cr03)3(BiO)2 Cr0,)6Hz0 as if the salt were a hydrated compound of bismuthyE tetracluomate and normal bisnzzctliyl cl~ro~nate.MUIR ON CERTAIN BISMUTH COMPOUNDS. 5. This salt appears as a finely crystalline very dense conipact powder of a brick-red colour inclining to orange. In its general reactions it comports itself in a manner similar to that detailed for the first chromate described. The action of hot caustic potash upon this salt appears to result in the production of the same chromate as was noticed in paragraph 3. I hope to prepare a quantity of this new chromate and to examine its properties. When heated the chromate now under consideration first becomes crimson then brown at which stage it is dehydrated and is finally conyerted before the blowpipe into a semi-fused grey-green mass.It was found that a temperature of 210-220" maintained for several hours was not sufficient to com-pletely dehydrate this salt. 6. I will now describe some investigations lately made upon bismuth salts other than chromates. 5 1. Actioyz of Chloriize on hot Biwmtlious Oxide. This action was carried out in the hope of obtaining an oxychloride of bismuth corresponding with POCl, VOCI, &c. as in the lower members of the nitrogen group this appears to be the best marked oxychloride. A quantity of pure dry bismuthous oxide was heated in a current of dry chlorine. Action began immediately and the only product appeared to be a white crystalline sublimate which was formed partly in the boat which had contained the trioxide partly in the colder part of the tube.The sublimate was deliquescent and closely resembled bismuth trichloride :-(a. 0.4192 gram gave 0-306 gram Bi,Os = 0.2747 gram Bi. (b.) 0.4192 )) 0.5425 , AgCl and 0.006 ) Ag. Calculated for BiC13. Found. Bismuth ............ 66.35 65.53 Chlorine ............. 33.65 32.47 This reaction is somewhat peculiar. 8 2. Action of Bromine on hot Bismuthous Oxide. 7. *4quantity of pure dry bismuthous oxide was gent'ly heated for several hours along with an excess of bromine in a long glass tube upon the end of which a small bulb had been blown. After. excess of bromine had been driven off the product was exposed to the air for some time and then analysed :- MUIR ON CERTAIN BISMUTH COMPOUSDS.27 (a.) 0.5778 gram gave 0.488 gram Bi& = 0.438 gram Bi. (b.) 0.5778 , 0.483 , , = 0,4335 ,) , (c.) 0.5778 , 0.222 , AgBrand0.008 , Ag. (a.) o 5778 , 0.235 , ,? , 0.008 , , 9 99 (B.) 0.661 0.259 ,? 3 0.010 > , Found. Calculated for F A \ BillBrjOll. I. 11. 111. 1v. V. Mean. Bismuth.. . 75.05 75.80 75-04 -75.42 L Bromine .. 18.19 -17.32 18.35 17.81 17-83 Oxygen . . 6.76 ---6-75 (by dif-ference.) 8. The new oxybromide presents the appearance of a cream-coloured amorphous powder it is non-deliquescent and is unaltered by ex-posure to the air. When heated it slightly darkens in colour but does not undergo decomposition; on cooling the original colour is regained.This salt is insoluhle in water whether hot or cold ; it is easily dis- solved by hydrochloric or nitric acid the addition of the latter if con-centrated causing disengagement of bromine. The formula of this oxybromide may be written as if the salt were a compound of bismuthyl bromide and bismuthous trioxide viz. 7BiOBr. 2Bi20,; or perhaps as an oxybromids of bisntutlzyl (Bi0)11Br702. Br-BiO \?BiOBr Br-BiO bio Br-BiO I Br-BiO BiOBr Br-BiO $iu BiO/O 9. By heating together bismuthous oxide and bismuthous bromide an oxybromide is formed which I believe to be bismuthyl bromide BiOBr. 9 3. Action of Ainnaonia on Oxybromidss and ON Oxide of Bisnzuth. 10. A quantity of the oxybromide Bi,Br,O,, described in a previous paper was heated to dull redness in a stream of dry ammonia.The salt darkened in colour a sublimate was produced which condensed in the colder portion of the tube in the form of a greyish-green powder while there remained in the boat semi-fused metallic-like globules. MUIR ON CERTAIN BISMUTH COMPOUNDS. 0.893 gram of the metallic globules gave 0.8929 gram bismuth ; there-fore this residue consisted of pure metallic bismuth. 11. A quantity of bismuthyl bromide BiOBr heated also to dull rcdness in dry ammonia yielded a smaller quantity of a similar sub- limate and a met'allic residue which was also shown on analysis to consist of pure bismuth :-@5735 gram gave 0.5743 gram bismuth. 12. Bismuthous oxide when heated to dull redness in ammonia was also reduced to metal:-O*678 gram of residue gave 0.675 gram bismuth.13. These reactions were carried out in the hope of obtaining a nitride of bismuth the results were unexpected. It is probable either that a nitride was produced at a lower temperature and was decomposed into metal and nitrogen at dull redness or that the ammonia being decomposed into nitrogen and hydrogen the nitrogen passed away and the phenomena noticed were the results of reduction in hydrogen. The production of water which was noticed during the process of heating showed that part of the ammonia at any rate had suffered decomposition. In order to ascertain whether a nitride was actually produced and was subsequently decomposed a further quan- tit(yof bismuthous oxide was gently heated in dry ammonia.The salt became darker in colour a small quantity of a yellow sublimate was produced and a dove-brown soft heavy powder remained in the boat. This powder was insoluble in water it was unacted upon by boiling caustic potash but was readily dissolved by strong nitric acid with copious evolution of lower oxides of nitrogen. (a,.) 0.456 gram gave 0.504 gram Bi203 = 0.4523 gram Bi. (b.j 0.737 , , 0.816 , , = 0.7323 , ) The heavy powder was therefore metallic bismuth. Hence it ap-pears that when bismuthous oxide is heated in dry ammonia to a temperature considerably below redness the ammonia is partly decom- posed and the metallic oxide is reduced in the hydrogen which is thus set free and that the nitrogen does not combine with the reduced metal.A similar reaction appears to take place in the case of the oxy-bromide of bismuth. I have already shown (this Journal 1876,ii 12) that the oxybromide Bi,Br6Ol5,is readilj reduced when heated in hydrogen. 14. The greyish-green sublimate produced when the oxybromide Bi8Rr6015, was heated in ammonia was submitted to analysis :-(a.) 0-53 gram gave 0.254 gram Bi,03 = 0.2279 gram Bi (b.) 0.322 , , 0.159 , , = 0.1427 , , (c.) 0.250 , , 0.262 , AgBr and 0.01 gram Ag. (d.) 0.5275 ,? boiled with KHO evolved KH, sufficient to neutralise 2.5 C.C. of standard acid (1C.C. = 0.049 gram H2S04). MUIR ON CERTAIN BTSXUTH COMPOUNDS. (e.) 0.518 gram boiled with KHO evolved NH3 sufficient to neutralise 2.2 C.C.of standard acid (1C.C. = 0.049 gram H2S04). Found. Calculated for cc 2BiBr3.5NH,. I. 11. 111. IT. V. Mean? Bismuth.. 42.68 43-00 44.32 --43.66 Bromine.. 48.79 -47.56 -47.56 Ammonia. 8.53 -I -8-06 7-22 7-64 15. This ammonio-bromide of bismuth is non-deliquescent nor is it decomposed by water it is readily dissolved by dilute acids. Strong nitric acid decomposes it with evolution of bromine. When heated fumes of bismuth tribromide are evolved and the salt is almost entirely volatilised a small quantity of what appears to be the oxybromide Bi,Br,O, remaining. A solution of this salt in hydrochloric acid allowed to evaporate over sulphuric acid deposited large very gale yellow tubular crystals. These crystals when dried by pressing between porous paper yielded the following numbers on analysis :-(a.) 0.2926 gram gave 0.117 gram Bi20s = 0.105 gram Bi., 0.456 , AgBr and AgC1. {o*f826 77” 99 0.294 Ag. 77 Calculated for 2BiBr3.5NH,C1.H20. Found. Bismuth ................ 35.43 33.82 Bromine ................ 40.49 40.19 Chlorine ............... 14.97 15.19 Deherain (Coinyt. rend. liv 724) has described a double salt analogous to this salt viz. 2BiC1,.5NH4C1. When added to water this double salt is at once decomposed with the production of a milky liquid probably containing oxychloride and oxybromide of bismuth. 16. The quantity of sublimate which was obtained when bismuthyl bromide (RiOBr) was heated in ammonia was too small to admit of much examination. It appeared to resemble the ammonio-bromide just described and the amoulit of bromine found in it closely corre- sponded with that required by the formula 2BiBr3.5NH, viz.48.79 per cent. 0.295 gram gave 0.3145 gram AgRr and 0.013 gram Ag = 48.69 per cent. bromine. § 4. Preparation of I€ypobismuthic Hydrate. 17. In a former paper (this Journal [el xiv 149) I have described the preparation of bismuthic hydrate Bi205.H20 by passing chlorine MUIR ON CERTAIN BISMUTH CORIPOUNDS. through very concentrated caustic potash kept at a boiling tempern- tnre in which bismuthous oxide was suspended. It'the caustic potash be somewhat less concentrated and the passage of chlorine be stopped when the suspended solid has been transformed into a chocolate-brown powder and if this powder after being washed free from alkali be boiled for a few minutes with a little concentrated nitric acid a reddish-yellow substance is obtained which when washed free from acid and dried over sulphuric acid presents the appearance of a brownish-yellow amorphous powder.A quantity of this powder prepared as just described gave the following results on analysis :-(a.) 0.5805 gram gave 0.545 gram Bi,Oa = 0.4891 gram Bi. (b.) 0,657 , , 0.614 , , = 0.551 , , (c.) 0.352 , ) 0.327 , , = 0.2935 , , (d.) 0,324 , , 0.302 , , = 0.271 , , (e.) 1.3135 , lost 0.056 after heating to 160" for some hours. Found. Calculated for I H20.Bi204. I. 11. 111. IV. V (mean). Bismuth .. 83.67 84.27 83.87 83-33 83.64 83.79 Water . .. . 3.58 --4-26 18. This salt to which I have given the name lzypobismuthic hydrate does not part with its water at 100" when heated to 130" for two hours 3.73 per cent. of water was given off the loss sustained at 160" (4-26 per cent.) was not increased when the temperature was raised to 190" and maintained at that point for an hour. After heating to 190" the colour of the salt had altered to a dark-brown. The colour did not further change on raising the temperature to 230° but decomposi-tion began at about 250° and on heating tlhe salt over a Bunsen-lamp the colour rapidly became light-yellow indicating the conversion of the bismutho-bismuthic oxide into bismuthous oxide. Hypobismuthic hydrate is insoluble in water whether hot or cold it is readily dissolved by hydrochloric acid with evolution of chlorine concentrated nitric acid very slowly dissolves this salt.19. I attempted to prepare a potassiam salt from this hydrate by boiling a quantity of it with strong caustic potash but no action appeared to ensue and the filtered liquid did not yield any salt containing a trace of bismuth either on evaporation or on neutralisation with acid. Schrader (Anw,.Ch. Pharm. exxi 204) has described a hypobis-muthic dihydrate Bi204.2H,0 obtained by a process similar to that described above.