JOURNAL OF THE CHEMICAL SOCIETY. I.-On Pyrophosphotriamic Acid. By J. H. GLADSTONE, Ph.D.,F.R.S. ITwas my intention in conjunction with my assistant and fkiend Mr. J. D. Holmes to follow up our previous papers on some of the amides of phosphoric acid* with a more complete investigation of the whole subject But our paper on the action of ammonia on sulphochloride of phosphorus was scarcely printed when Mr. Holmes was taken seriously ill and his death last mid- summer has deprived the world of a careful experimenter and a good man. I feel his loss the more because he had many thoughts and observations connected with these compounds of phosphorus which he never committed to writing. Oa looking over our note-books I find a tolerably complete history of a remarkable acid amide which with a few additional experiments will form the present communication.If dry ammonia gas be allowed to stream slowly into a flask containing oxychloride of phosphorus kept cool by being immersed in water the liquid is gradually converted into a white solid mass by the absorption of two equivalents of ammonia. If at that point the flask be immersed in water at 100"C. the mass will be found capable of absorbing two more equivalents of ammonia and on the addition of water to the white substance thus produced there results an insoluble amide the subject of the present inquiry. In order to obtain it pure the oxychloride of phosphorus employed must be free from pentachloride but it is not necessaryto attempt to free it from hydrochloric acid.During the latter portion of the * Journal Chem. SOC.,1864 p. 225 and 1865 p. 1. VOL. XIX. B GLADSTONE ON PPROPHOSPHOTRIAMIC ACID. process it is desirable to break up the solid mass from time to time in order that all parts of it may be exposed to the gaseous ammonia; and if this be properly done the contents of the flask will be found to have increased in weight nearly if not quite 44 per cent. The white amorphous powder produced by the action of water must be washed with cold water till the washings give no indica-tion of a chloride and then it is better to finish the washing with a little dilute alcohol. The compound thus obtained is ta,steless but when moistened it reddens blue litmus paper and it effervesces with solutions of alkaline carbonates.When suspended in solutions of metallic salts it usually decomposes them entering into combination with the metal and that in the presence of the liberated acid. These salts so easily formed are all insoluble or very sparingly soluble in water like the acid itself even the salts of the alkalis. Another remarkable circumstance connected with this acid is that it is capable of combining with 1,2,3,or 4 atoms of the base according to the peculiarities of the metal itself or the way in which it is presented. This compound though almost insoluble in water is very slowly attacked by it especially at a high temperature with the produc- tion of pyrophosphodiamic acid. When boiled with dilute hydro-chloric acid it is speedily resolved into phosphoric acid and ammonia pyrophosphodiamic acid being an intermediate product.When heated with strong sulphuric acid it instantly dissolves and this solution also contains yyrophosp hodiamic acid. The following analyses were made of different preparations of the substance dried at 1GO0 C. :-I. 0.3315 grm. boiled with hydrochloric acid and the ammonia determined in the usual manner gave 1.243 grm. of am-monio-chloride of platinum. II. 0.197 grm. gave 0.755 grm. of ammonio-chloride af platinum. 111. 0.197 grm. decomposed in the same way gave 0.247grm. of pyrophoaphate of magnesium. IV. 0.2595 grm. gave 0-987 grm. of ammonio-chloride of platinum V. 0.2445 grm. gave 0.309grm.of pyrophosphate of magnesium.VI. 0*18&5grm. regained from its ammonium salt gave 0.705 grm. of ammonio-ohloride of ~latinum. GLADSTONE ON PYROPHOSPHOTRIAMIC ACID. VII'. 0.225 grm. of substance regained from its combination with copper gave 0.2825 grm. of pyrophosphate of magnesium. VIII. 0.320 grm. burnt with oxide of copper gave 0.114grm. of water. These numbers when reckoned to 100 parts give I. 11. 111. IT. v. TI. VII. VIII. Phospho~s.... -35.02 -35'29 -35-38 -Nitrogen .... 23.64 24.03 -23-85 -23-96 --I-Hydrogen .... -3-93 agreeing very closely with the numbers deduced from the formula P,N,*,C),* Calculated. Mean of Analyses. Phosphorus ........ 62 35.43 35-23 Nitrogen ........ 42 24-00 23-84 Hydrogen ........ 7 4-00 3.93 64 Oxygen ..........-36-57 - 175 100.00 This may be viewed as the third member of the series of amides of pyrophosphoric acid of which the first two have already been described by me ; and it should by analogy be termed pyrophos- pho triamic acid.Ppophosphoric acid .................... P H4Q7 Pyrophosphamic acid .... P2NH@6 or P2(NH2) H3Q6 Pyrophosphodiamic acid .... P2N2H6Q5or P,2(NH2)H,8 Pyrophosphotriamic acid .... P2N3H@4 or P23(NH2)H Q4 The reaction by which this substance is produced by the treat- ment of oxychloride of phosphorus with ammonia and water in succession may be briefly expressed thus :-Z(PC13Q + 4NH3) + 2H20 = P2N3H@4 + 6HC1+ 5NH3 just as in the production of pyrophosphodiamic acid formerly de- scribed-2@?c130 + 2NH3) + 34Q = P2N2H6&& + 6HC1+ 2NH3 bat in both cases there are intermediate products not recognized B2 GLADSTONE ON PYROPHOSPHOTRIAMIC ACID.in the above equations. I reserve the fuller consideration of what takes place when ammonia is passed over oxychloride of phosphorus till a future occasion SALTS. If the rational formula of this acid be that above given it might be expected that only one equivalent of hydrogen would be replaceable by a metal or in other words that pyrophosphotriamic acid would be monobasic just as the -diamic acid is bilasic and the -amic acid is tribasic. The analysis of its salts shows indeed that such monobasic compounds are produced with the alkali- metals and many others but it also shows that most metals are capable of displacing one or more equivalents of that hydrogen which we are apt to consider as more intimately associated with the nitrogen.SrLvER-sALTs.-Moiiometallic.-Tf a solution of nitrate of silver be added to an aqueous solution of pyrophosphotriamic acid it gives a white gelatinous precipitate. But it is not easy to prepare in this way a quantity sufficient for analysis and a portion so pro-duced gave n determination of silver which led to the conclusion that the salt was impure. A better method is to suspend the acid in cold water and add a solution of nitrate of silver when a floccu-lent precipitate subsides and becomes granular. It is white amorphous and insoluble in water ; dilute nitric acid or ammonia will dissolve out a little silver and leave the pure monometallic salt.This salt is decomposed at once by hydrochloric acid ; and this affords a ready means for its analysis as the pyrophosphotriamic acid itself is converted on boiling into phosphoric acid and ammonia which can be determined in the usual way. The following determinations were obtained :-I. 0.259 grm. of silver-salt washed with dilute ammonia gave 0.133 grm. of chloride of silver and 0*208of pyrophos-phate of magnesium. 11. 0.241 grm. similarly washed gave 0.122 grm. of chloride of silver and 0.581 grm. of ammonio-chloride of platinum. 111. 0.298grm. of salt washed with dilute nitric acid gave 0.1515 grm. of chloride of silver and 0.235 grm. of pyro-phosphate of magnesium. IV. 0.285 grm. similarly washed gave 0.145 grm.of chloride of silver and 0.679 grm. of ammonio-chloride of platinum. GLADSTONE ON PYROPHOSPHOTRIAMIC ACID. This agrees closely with what ought to be obtained from a sub-stance having the composition P,N,H6AgQ4. Calculated. I. 11. 111. IV. Phosphorus .. 62 21.98 22-42 -22.01 -Nitrogen . . .. 42 14.89 -15.11 -14.94 Hydrogen .... 6 2.13 I -I -Silver ........ 108 38-30 38.64 38.09 38.26 38.29 Oxygen ... . .. 64 22.70 282 100*00 ~irnetaZZic.-If a feebly ammoniacal solution of nitrate of silver be added to a solution of pyrophosphotriamic acid there precipi- tates a yellowish salt. Or if the monometallic compound just described be treated with such an ammoniacal salt of silver in excess it becomes of a bright yellow colour heavy granular and easily washed by decantation.When dry it forms an orange-yellow powder. Dilute nitric acid or ammonia converts it at once into the white monometallic salt. Acetic acid attacks it but slowly even when strong and at a boiling temperature. It was analysed by decomposition with hydrochloric acid. I. 0.509grm. of the yellow salt gave 0.442grm. of chloride of silver and 0-675grm. of ammonio-chloride of platinum. 11. 0.5745 grm. gave 0-4995grm. of chloride of silver and 0.252 grm. of pyrophosphate of magnesium. 111. 0.286 grm. gave 0.2485 grm. of chloride of silver and 0.3695 grm. of ammonio-chloride of platinum. IV. 0404 grm. gave 0.3515 grm. of chloride of silver and 0.183 grm. of pyrophosphate of magnesium. These numbers agree well with the composition P,N3H,Ag3Q4.Calculated. Found. I. 11. 111. IV. Phosphorus .. 62 12.50 -12.25 -12.65 Nitrogen .... 42 8.47 8.32 -8.10 -Hydrogen .... 4 0.81 --Silver ........ 324 65132 65.34 65.46 65-39 6548 Oxygen 64 12.90 --.. -496 100*00 GLADSTONE ON PYROPHOSPHOTRIAMIC ACID These two silver-salts white and yellow and their ready con-vertibility into one another afford a good test for pyrophospho- triamic acid. BARIUM-SALTS. -MonometaZZic. -This salt was prepared by diffusing the acid through a solution of chloride of barium and carefully neutralising the liberated hydrochloric acid by a few drops of ammonia. It was decomposed byhydrochloric acid the dif-ferent constituents being determined in the usual way.I. 0.429 grm. gave 0.2045 grm. of sulphate of barium and 1.1795 grm. of ammonio-chloride of platinum. 11. 0.3465 grm. gave 0.1665grm. of sulphate or"barium and 0.3145 grm. of pyrophosphate of magnesium. These numbers indicate the formula P2N,H6BaQ,. Calculated. Found. I. 11. Phosphorus .. 62 25-56 -25-34 Nitrogen .... 42 17*31 17*24 -Hydrogen .... 6 2.47 Barium ...... 68.6 28.28 28.06 2827 Oxygen ...... 64 26.38 242.6 100*00 .Dimetallic.-When pyrophosphotriamic acid was suspendedin an excess of an ammooiacal solution of chloride of barium it I combined with twice as much of the metal. The following analyses were made :-I. 0.2335 grm. of salt gave 0.174grm. of sulphate of barium and 0.4895 grm.of ammonio-chloride of platinum. 11. 0.2445 grm. gave 0.1835 grm. of sulphate of barium and 01793 grm. of pyrophosphate of magnesium. These indicate the composition l',N,H,Ba24&. Calculated. Fpund I. 11. Phosphorus .. 62 20-00 -20.48 Nitrogen .... 42 13-54 13-14 -Hydrogen .... 5 1-60 -Barium ...... 137.24 4.23 43-84 4418 -Oxygen ...... 64 20.63 -310.2 GLADSTONE ON PYROPHOSPHOTRIAMIC ACID. LEAD-SALTS. -Lead is capable of entering into combination with pyrophosphotriamic acid in three different proportions. MononaetaZZic.-If the acid be treated with a solution of nitrate of lead the result is a mixture of the compounds of 1 and 2 atoms of the metal. If however the solution be rendered decidedly acid with nitric acid a pure mono-metallic salt may be produced.0.203 grm. of the acid thus treated gave 0.327 grm. of salt which indicates a compound of the formula P,N,H,PbQ4. The exeess of weight being due to the addition of lead and the removal of a corresponding amount of hydrogen gives the follow- ing percentage :-Calculated. Found. Lead . 37-3 per cent. 38.1 per cent. Dimeta&.-To produce this compound the acid was suspended is water and an excess of a strong but slightly acid solution of acetate of lead was added. A dense white granular precipitate was the result. It was analysed in the usual way. 0.354 grm. of salt gave 0*2805grm. of sulphate of lead and 02035 grm. of pyrophosphate of magnesium. This agrees sufkiently with the formula P2N,H,Pb,Q4.Calculated. Found. Phosphorus .. 62 16.32 16.05 Nitrogen .... 42 11.05 -Hydrogen.. .... 5 1.32 -Lead .......... 207 59-47 53.95 Oxygen.. ...... 64 16-84 -380 100*00 This compound is not turned yellow by iodide of potassium except on the addition of hydrochloric acid. TrimetaZZic.-When pyrophosphotriamic acid was warmed with basic acetate of lead it combined with a larger portion of the metal. The following analyses were made :-I. 0.3405grm. of salt gave 0.321 grm. of sulphate of lead and 0-1535of pyrophosphate of magnesium GLADSTONE ON PYROPHOSPHOTRIAMKI ACID. 11. 0.2365 grm. gave 0.175 grm. of sulphide of lead and 0.3165 grm. of ammonio-chloride of platinum. This agrees with the formula P,N,H,Pb,B,. Calculated.Found. I. 11. Phosphorus .. 62 12.85 12.59 -Nitrogen .... 42 8-70 -8.39 Hydrogen ... . 4 0.83 -Lead ...... 310.5 64.35 64.40 64-08 c Oxygen ...... 64 13-27 -482.5 100*00 THALLruM-sALT.-Pyrophosphot~amic acid treated with nitrate of thallium gives a heavy white compound which is easily decomposed by rather strong nitric acid. CoPPER-sALTs.-Both neutral and ammoniacal salts of copper give up their metal to pyrophosphotriamic acid. Monometallic.-The acid when treated with a solution of nitrate of copper to which some drops of nitric acid had been added gave a pale blue compound. Ou analysis this was found to contain rather more copper than a pure monometallic salt should have done ;but it consisted mainly in all probability of such a com-pound.Dimetallic.-0.164 grm. of the acid digested awhile with a solution of acetate of copper gave a greenish salt which when dried at 100' C.,weighed 0.215 grm. These numbers indicate that two equivalents of hydrogen had been replaced by copper though perhaps the conversion had not been complete. The increased weight ought by calculation to have been 0.220. If some of the acid be thrown into a solution of a copper-salt in excess of carbonate of ammonium an effervescence takes place and there results a green powder insoluble in ammonia but from which dilute acids dissolve out the copper. I. 0-236 grm. of this salt gave 0-080 grm. of oxide of copper and 0.646 grm. of ammonio-chloride of platinum. 11. 0-304grm. gave 0*103 grm. of oxide of copper and 0.285 grm.of pyrophosphate of magnesium. This was certainly P,N,H,Cu2Q4. GLADSTONE ON PYROPHOSPHOTRIAMIC ACID. Calculated. Found. I. IT. Phosphorus .... 62 26-25 -26.18 Nitrogen ...... 42 17.78 17.17 -Hydrogen ...... 5 2.12 -Copper ........ 63.2 26.76 27-04 27-03 Oxygen ........ -64 27-09 - -236.2 100*00 ZINC-SALT.-The acid decomposes chloride of zinc forming a white pyrophosphotriamate. CaDMIuM-sALT.-It forms a white compound also when treated with chloride of cadmium. IRo~-sALT.-MonometaZZ~c,-If the acid be digested with a solution of ferrous sulphate a salt of a yellow-drab colour is pro- duced which resists the solvent power of dilute acids. 0.075 grm. of substance increased in this way to 0.089 grm.which points to the formula P,N,H6FeQ4. The salt obtained ought to have weighed 0.086 grm. ; but it probably contained a trace of ferric oxide mixed with the ferrous compound. I have not succeeded in preparing any ferric pyrophosphotriamate though the attempt has been made with ferric chloride acetate and ammonio-citrate. This is the more remarkable as pyrophos- phamic acid and phospboric acid itself show such a readiness to combine with iron in that condition. CoBALT-SALT.-ni~etalzic.-The acid digested with a slightly ammoniacal solution of nitrate of cobalt forms a compound of a beautiful violet colour not decomposed by diliite hydrochloric and but slowly by dilute sulphuric acid. 0.136 grm. gave thus 0-177 grm. of salt which is sufficiently near to the theoretical amount to show that the composition was P,N,H,Co,B,.CJculated. By synthesis. Cobalt .. 25.6 per cent. 24.3 per cent. The same salt seems to be produced when the acid is treated with an ordinary solution of chloride of cobalt but an analytical experiment gave also in this case less than the required percentage of metal. NICKEL-SALT.-A feebly ammoniacal solution of sulphate of nickel gives a bright green pyrophosphotriamate. WADSTONE ON PYROPHOSPHOTRIAMIC ACID-MAN GANEsE-BALT. -Chloride of manganese gives a yellowish salt of this acid. CHROMIUM-SALT.-A green compound may be produced by means of acetate o€ chromium. MAGNEsIUM-SALT.-This was produced by warming the acid with t?n ammoniacal solution of magnesia and washing with water containing a little ammonia and afterwards with pure water.On analysis it appeared to be a mixture of monometallic and dime-Uic salts. ~oTAssIUM-SALT.-~onorneta~~ic.-~pphosphotriamicacid de- composes carbonate of potassium without dissolving. The white almost insoluble salt is readily decomposed by acids. The follow- ing determinations mere made :-I. 0.312 grm. of salt gave 0.356 grm. of potassio-chloride of platinum. 11. 0.329grm. gave 0.3402 grm. of pyrophosphate of mag-nesium. 111. 0.2985 grm. gave 0.3355 grm. of potassio-chloride of platinum. This agrees with the numbers deduced from the formula P,N,H,KB,. Calculated. Found. I. 11. 111. Phosphorus .. 62 29.10 -28.87 -Nitrogen .... 42 19.72 Hydrogen ....6 2.82 Potassium ,.. 39 18.31 Oxygen . . . . . 64 30.05 213 100*00 AMMoNIUM-sALP.-The acid forms a sirnihr sparingly soluble ammonium-compound which cakes together in small white lumps and readily parts with the base when treated with dilute acids in the cold. I. 0-129grm. of salt gave 0.5946 grm. of amrnonio-chloride of platinum. 11. 0.2095 grm gave 0*9805 grm. of ammonio-chloride of platinum. 111. 0%428 grm. eve 0.3995 grm. a€ pyrophosphate of mag-nesium. GLADSTONE ON PTROPHOSPHOTRIAMXC ACID. IV. 0.220 grm. gave 1.014 grm. of ammonioddoride of platinum. This indicates the compound P,N,H6 (N€14)Q4. Calculated. Found. I. 11. 111. IT. Phosphorus .. 62 32-29 32.61 -I-Nitrogen .... 56 29-17 28.90 29-34 -28-90 Hydrogen ....16 5.21 -c -Oxygen ....a . 64 33.33 --192 100*00 MERCuRY-s(BLT.-TetrametalZ~c.-Tt was observed early in the investigation that if pyrophosphotriamic acid be boiled with oxide of mercury the oxide loses its colour and forms a white compound which is insoluble in dilute nitric or hydrochloric acid. This mer- eury-salt may be also prepared by diffusing the acid through a solution of corrosive sublimate but Mr. Holmes seems always to have employed a slightly acid solution of the double chloride of mercury and ammonium. It is a heavy white granular powder which becomes yellowish and eventually dark-coloured when exposed to light. Iodide of potassiuni first turns it scarlet and then dissolves oub the mercury. The following analyses were made :-I.0*4175 grm. of salt gave 0.3405 grm. of dphide of mercury. 11. 0.5405 grm. gave 0-5 grm. of sulphide of mercury. 111. OW6 grm. gave 0*%4 grm. of sulphide of mercury and 0.8305 grm. of ammonio-chloride of platinum. IV. 0.3415 grm. gave 0.277grm. of sulphide of mercuryqand 0*1305grm. of pyrophosphate of magnesium. These numbers require the farmula P,N,H,Hg,B,. Calculated. Found I. 11. 111. IT. Phosphorus . . . 62 10-86 --1Qt67 Nitrogen ...... 42 7.35 -c 7.50 -I Hydrogen. . . . 3 0.53 --Mercury ...... 400 70.05 7'0.31 70.25 69.96 6992 Oxygen.. 64 11.21 --572 i08*00 GIADSTOm OX PraopHoptPEOTRrnC ACID. PLbTrNm-sdLT.-when pyrophosphotriamic acid is treated with a strong aqueous solution of platinic chloride a bulky yellowish compound is fbrmed.This is entirely decomposed wher washed with water in presence of the liberated acid; but it may be safely washed with alcohol and then water has not the same effect upon it. 0*097grm. of the original acid gave 0.207 grm. of this platinum-compound which shows that two equivalents of the metal must have entered into combination displacing no doubt four equivalents of hydrogen; the formula being PONS H,P t”,&. Calcnlated. Found. Platinum.. 63.7 per cent. 54.1 per cent. An attempt to prepare a salt of gold in a similar manner was nnsuccesaf$. The rational formula P,(NH,),HB has been given above for this pyrophosphotriamic acid but the element8 are susceptible of another arrangement which brings them more closely in accord-ance with the formula of pyrophosphoric acid and indicates four equivalents of hydrogen as in a different position to the remain- ing three.Pyrophosphoric acid .. .. P,H443 Pyrophosphotriamic acid .. ’ p,H4(pa)J The following table exhibits at a glance the number of hydro- gen atoms displaced by different metals as far as the salts have been hitherto examined quantitatively :-3 eqs. 4eqe. Ammonium.. ............ I- Potassium .............. Magndum.. ............ Barium ................ Leful.... ................ Copper.. ............... - Iron.. .................. -I- cobslt .....0. ............ Sgver .................. Mercury ................ Platinum.. i.0.0 00 i0 0.