MR BUCKTON ON THE DEPORTMENT OF V.-Observations upola the Deportment of Diplatosamine with Cyanogen. BY G. B. BUCKTON, EsQ.,F.L.S. The peculiar deportment exhibited by aniline toluidine and several other volatile organic bases when exposed to the action of cyanogen rendered it desirable to investigate the behaviour of some of the fixed bases in the same direction. At the request of Dr. Hofmann and with his supervision I have undertaken some experiments on this DXPLATOSAMINE AND CYANOGEN. subject the results of which I beg to communicate to the Chemical Society. The substance on which I have worked is the remarkable alkaloid discovered by Reiset obtained by the action of ammonia upon the green salt of Magiius long known under the name of Reiset’s first platinum-base for which more recently the shorter name of diplato- samine has been proposed.On passing a stream of cyanogen through a moderately concen- trated solution of diplatosamine free from carbonic acid the gas is slowly absorbed and after some time a yellowish-white crystalline substance is deposited which continues to form until the solution changes colour from the partial decomposition of the cyanogen at which point it is desirable to suspend the operation. This substance is soluble to a slight extent in cold but much more readily in boiling water from which it may be recrystallised without difficulty. It then appears as a mass of minute colourless crystals which under the microscope exhibit the form of hexagonal plates and frequently arrange themselves in regular stellar groups.It is how- ever difficult to obtain them without a yellow tinge from traces of decomposed cyanogen which obstinately adhere even after three zrys-tallisations. When heated in the air the substance spontaneously takes fire and smoulders like tinder leaving as sole residue a light sponge of platinum. It freely evolves ammonia when heated in a dry test-tube; but the presence of cyanogen could not be detected by the usual test of potassa proto-sesquioxide of iron and hydrochloric acid. On analysis this substance gave the following numbers I. 0.3465.grm. of substance dried at looo left on ignition 0.2410 , ,,platinum. IF. 0.4005 , , substance gave 0.2780 , , platinum. 111. 0.4588 , , substance when burnt with soda-lime yielded 1*4700 , , ammonio-chloride of platinum equivalent to 0.0922 , , nitrogen.IV. 0.3957 , , substance yielded 1.2775 , ,,ammonio-chloride of platinum equal to 0*0801 , , nitrogen. These numbers correspond to the following percentages I. ’ 11. 111. IV. Platinum . . . 69.55 69.41 -Nitrogen . . . -20.09 20.24 MR. BIJCKTON ON THE DEPORTMENT OF and also to the formula Pt NH Cy as is exhibited in the annexed table Theory. Experimental mean. r--7 7*-7 1 equiv. of Platinum . . . 98.68 69.64 69.48 2 , , Nitrogen . . 28.00 19.78 20.16 3 , , Hydrogen. . . 3.00 2.12 -2 , , Carbon . . . 12.00 8.46 --____I 141.68 100*00 These analyses show that the action of cyanogen upon diplatosa- mine far from being analogous to that on aniline toluidine &c.(which as is well known combine directly with the gas,). gives rise to the same compound which Reiset obtained by saturating the base with hydrocyanic acid and which he considered as the cyanide of his second series viz. as the hydrocyanate of platosamine or as the cyanide of platosammoniurn. Pt H2}N. HCy orF[}N. Cy. I have carefully compared the substance prepared by the action of cyanogen with that obtained by Reiset’s method and find them identical in all respects. It may be mentioned here that a very convenient method of obtaining the compound in considerable quantity consists in adding cyanide of potassium to the chloride of diplatosammonium (the direct product of the action of an excess of ammonia upon protochloride of platinum).By this process the tedious operation of isolating the base is avoided ; the precipitate requires only two or three crystallisa- tions to remove the soluble chloride of potassium. The formation of the cyanide by the action of cyanogen upon a SO-lution of diplatosamine is readily intelligible. The mother-liquor of the crystals was found to contain a con-siderable quantity of carbonate of ammonia and moreover the carbonate of diplatosamine. This compound was identified by con- version into the sulphate and analysis of the latter. It is evident that the first action consists in a decomposition of water the elements of which unite with cyanogen producing hydro- cyanic and cyanic acids; the former giving rise to the crystalline cyanide ammonia and water PtH N 0.HO + HCy=PtH N . Cy+ NH,+2 €30; DXPLATOSAMINE AND CYANOGEN. the latter inducing the transient formation oi cyanate of diplatosa- mine which by assimilation of the elements of water is immediately converted into the carbonate of this alkaloid and carbonate of am- monia. Pt H N 0,Cy 03-4 HO=Pt H N 0 CO +NH 0CO,. As the general deportment of the salt Pt H N Cy seemed to be somewhat anomalous and in many respects different from that of an ordinary cyanide (the usual tests failing altogether to indicate the presence of cyanogen) I have studied the behaviour of this compound with various reagents in order if possible to obtain new data by which to elucidate its constitution.The cyanide in question is soluble in potassa without decomposition. It imitates in this respect the deportment of cyanide of silver. It is also soluble without change in hydrochloric acid although the crystals deposited from the solution assume a somewhat different shape and a yellow colour.* It may be recrystallised without decomposition also from dilute sulphuric acid. Concentrated sulphuric and nitric acids however decompose it ; but the products of these reactions have not been farther examined. The action of nitrate of silver upon the cyanide is very remarkable and appears to throw much light upon the true nature of this substance. When nitrate of silver is added to an aqueous solution of the cya- nogen-compound a copious white and curdy precipitate immediately falls in outward appearance resembling cyanide of silver and like the latter salt soluble in ammonia.On evaporating the solution filtered off from the precipitate at a gentle heat a crop of beautiful crjrstals made their appearance which lost their transparency on carrying the evaporation to dryness. On raising the temperature beyond this point they suddenly took fire and left a residue of pure platinum. In the conception of the substance being cyanide of platosammonium * The substances crystallised from potassa (I.) and from hydrochloric acid (11.) were identified by analysis. I. 0.4065 grm. of substance gave 0,2830 ,) , platinum. 11. 0.4685 , ,? substance gave 0.3250 ? 9t platinum. The experimental and theoretical percentages are- Mean of Theory.Experiment* experiments. 1. 11. Platinum . . . 69.64 69.61 69-37 69.49 MR* BUCKTON ON THE DEPORTMENT OF I was inclined to consider these needles as the nitrate of platosamine when the reactions would have been represented by the equation PtH,N.Cy+AgNo,=Pt H,N.NOG+AgCy. In order to verify this equation the needles were subjected to analysis when the following results were obtained I. 0.5030 grm. of this salt gave 0.2525 , , platinum. 11. 0.3930 , , from another preparation 0,1960 , , platinum. These numbers far from agreeing with the formula of the nitrate of platosamine exhibit on the contrary a close accordance with the theoretical values required by the composition of the nitrate of Reiset’s &st compound as may be seen by the following com- parison Theory.Experiment. r-pA--7 7-7 Pt H3N NO Pt H6 N NO I 11. Platinum . 55-53 50.68 50.19 49.87 As the determination of nitrogen in the nitrate presented some diffi- culties to vary the analysis and furnish a means of corroboration a solution of the cyanide was precipitated with sulphate of silver the filtrate evaporated and the platinum determined in the sulphate thus obtained- 0.4080grm. of substance gave 0.2215 , , platinum. This result perfectly corroborates the inference drawn from the former analysis namely that the action of nitrate of silver upon the cyanide under examination gives rise to the formation of a salt not of platosamine but of diplatosamine (Reiset’s first base).For the sake of comparison I subjoiu. the theoretical percentage of the salt Theory. Experiment. Platinum. . . . . 5461 54-22 The unexpected results obtained in the examination of the soluble compound produced by the action of the silver-salt upon the cyanide compelled me more carefully to investigate the white precipitate which hitherto I had regarded as cyanide of silver. I found at once that this precipitate is by no means cyanide of silver but that it con-tains platinum as one of its constituents. The quantitative analysis of this white compound presented how- DIPLATOSAMTNE AND CYANOGEN. 31 ever some diffticulty from the extreme tenacity with which the cyano- gen holds the combined metals. No constant results could be obtained by fusing with carbonate of soda and potassa ignition with soda lime or the combined action of nitric acid and chlorate of potassa.The analysis however succeeded without dificulty when the salt under examination was dissolved in strong ammonia and immediately pre- cipitated with sulphide of ammonium when pure sulphide of silver is thrown down the whole of the platinum remaining in solution. This solution when evaporated yielded at first beautiful iridescent crystals which subsequently left pure metallic platinnm on ignition. In this manner the following results were obtained I. 0.6019 grm. of substance gave 0.2884 , , sulphide of silver equal to 0.2511 , , metallic silver and 0.2305 , , platinum. 11. 04555* , , substance gave 0.1745 , , platinum.These numbers correspond to the following percentages I. 11. Platinum . . . 38.29 38.30 Silver . . . . 41.71 -and prove that the white precipitate is nothing but platino-cyanide of silver Ag Pt cy, as is exhibited in the following comparison of the experimental results with the values required by theory. Theory. Mean of experiments. r---2 equiv.of Cyanogen . . . 52.00 20.15 -1 , , Platinum . . . . 98.68 38.10 38.29 1 , ,) Silver . . . . . 108-00 41*75 41.71 1 , , Platino-cyanide of } 258-68 silver . . . . 100-00 This conclusion was fully borne out by the deportment of the silver- salt with reagents when compared with that of the platino-cyanide obtained by the usual method. Detailing the analysis of this substance I have mentioned that on treating the ammoniacal solution of the cyanide with hydrosulphuric * The silver was lost.MR BUCKTON ON THE DEPORTMENT OF acid iridescent needles are obtained. These needles are the corre- sponding platino-cyanide of ammonium. A similar result was found when the silver-salt was treated with potassa with which on ebullition it gave a heavy black precipitate containing all the silver and a colourless solution which yielded long needles of a purple hue by reflected and yellow by transmitted light. These crystals change to a deep yellow when heated and then fuse to a mass of carbon and platinum. The aqueous solution of this compound gives first a bright orange precipitate with the nitrate of the siiboxide of mercury which speedily changes to a cobalt-blue on increasing the quantity of the mercury-salt.It need scarcely be mentioned that this deportment in all respects agrees with that of the platino-cyanide of potassium described by Gm elin which moreover was satisfactorily proved by direct comparison of the two salts. The formation of platino-cyanide of silver from the cyanide which forms the subject of the present communication fully explains the simultaneous production of a salt of Reiset’s first base. The reaction is expressed by the following equation 2 Pt H N . Cy + Ag NO6= Pt H6 N . NO6+ Ag. PtCy,. To obtain a quantitative control of the correctness of this equation a weighed portion of the cyanide was decomposed by nitrate of silver.The precipitated salt was carefully dried upon a weighed filter and the quantity obtained compared with the amount required by theory. I. 0-2398grm. of salt produced 0.2275 , , platino-cyanide of silver. 11. 0.5935 , , another specimea gave 0.5425 , , platino-cyanide of silver. The quantity required by theory and obtained by experiment re- duced to 100parts is as follows Theory. Experiment. I. 11. 91-29 90.70 91.40 The facts observed in the study of the crystalline compound which is formed by the action of hydrocyanic acid or cyanogen upon the oxide of diplatosammonium suggests a mode of viewing the constitu- tion of this substance which is different from that hitherto adopted. ’ If with M. Reiset we consider this compound as the cyanide of platosammonium we are forced to admit that this substance owes its origin to a very singular play of affinity inasmuch as the influence of DIPLATOSAMINE WITH CYANOGEN.hydrocyanic acid on the oxide of diplatoeammonium gives rise to the cyanide of platosammonium whilst on the other hand a metallic solution reconverts this compound into a salt of the original base. It appeared much simpler to regard the compound in question as a salt of the base from which it is derived viz. as a platino-cyanide of diplatosannmoniuni which is isomeric with the cyanide of platosammo-aium. 2 Pt H N . Cy=Pt H N,. PtCyz. This formula explains equally well the formation of the substance by the action of hydrocyanic acid upon the oxide of diplatosammo-nium 2PtH6NgO+4HCy=Pt H6N,.PtCy,+2NH,Cy+% HO but the interpretation of its behaviourwith silver-salts becomes infinitely simpler as the whole change is reduced to a case of ordinary double decomposition.ft H6 N,. Pt Cy + Ag NO = Pt H N . NO + Ag Pt Cy,. t-,-J L-y-L L-v-J ----I Platino-cyanideof Nitrate of Nitrate of Platino-c yanide diplatosammonium silver. diplatosammonium. of silver. To test the accuracy of this view experimentally I prepared a quantity of hydroplatino-cyanic acid by treating the mercury-salt with hydrosulphuric acid. On saturating this acid with the oxide of diplatosammonium I obtained at once a colourless crystalline sub- stance which could not be distinguished from the cyanide previously described either by appearance or behaviour with reagents.The same salt may be more conveniently procured by adding platino-cyanide of potassium to the chloride of diplatosannmonium. On recrystallising and drying at looo 0.2084 grm. of substance gave on ignition 0*14?4!6, , platinum in accordance with the formula Pt H N, Pt cy, the calculated and experimental numbers in 100 parts being Theory. Experiment. Platinum . . . 69.64 69.34 On reference to Reiset’s excellent paper upon the platino-bases it doesnot appear that he attempted the construction of the cyanide of platosammonium by directly operating upon a salt of the correspond- VOL. IV.-NO. XIII. I) DR. GLADSTONE ON THE EXPLOSIVE COMPOUND ing base considering doubtless that the substance would prove itself identical with that previously described by him.As a last step it appeared desirable to try the preparation of the true cyanide of platosammonium as it was not improbable that a com- pound might be thus obtained similar in composition but differing in its molecular arrangement and consequently presenting some possible discrepancies in its chemical and physical properties. Accordingly I digested a few grammes of the chloride of platosam-nionium with an excess of cyanide of silver ; the decanted liquid was found to yield on concentration fine and regular needles of a pale-yetlow colour. These crystals proved to be much more soluble in water and ammonia than the platino-cyanide of diplatosammonium from which they also materially differed in their deportment with reagents.0.4695 grm. of substance gave 0,3256 , , platinum which agrees with the formula Pt H,N cy the numerical percentages being Theory. Experiment. Platinum . . 69.64 69.35 Hence it is evident that there are two substances of the same corn-position the one by the mode of formation and behaviour with re& agents proved to be a salt of a platinum-base with a platinum-acid (platino-cyanide of diplatosammonium) the other as far as we can judge from the method of preparation the true cyanide of platosam- monium. The latter substance appears to call for closer attention than I have been able to bestow upon it; but I hope at a future time to have the honour of laying the results of an extended examination before the Chemical Society.