hl2> Dr. J. H. Gladstone on Pyrophosphoric Acid [May 23, 



If either of these compounds be strongly heated, hydrochloric acid, or 

 chloride of ammonium, is given ofi, and there remains pliosphonitryle^ 



Bj^ the action of hea,t on the substances already described, other com- 

 pounds may also be prepared, thus : — 



Pyropliosplio-nitrylic acid. — If pyropliospho-triamate of potassium be 

 heated at a dull redness, it loses two-thirds of its nitrogen as ammonia, 

 leaying a fused mass, which is insoluble in water, but forms compounds 

 when treated with silver or copper salts. These have the composition 

 ■of pyrophospho-nitrylates, ^4- pyrophospho-triamic acid 



itself be similarly heated, it parts with one molecule of ammonia, and 

 gives a body, P2 INT^ 0^, isomeric with pyrophospho-nitrylate of 

 ammonium, which is speedily resolved by damp air into pyrophosphamic 

 acid and other compounds. 



The process adopted for the analysis of these acid amides was that of 

 boiling them with strong hydrochloric acid. This converts them all into 

 ammonia and ordinary phosphoric acid, Vvhich were determined in the 

 usual manner. 



Theoretical Constitution. 



A difficulty in understanding the formation of the bodies above 

 described from oxj^chloride of phosphorus arises from the fact that they 

 contain P^... or P^..., while the original phosphorus compound contains 

 but one atom of that element. The lollowiDg considerations may fur- 

 nish a probable explanation and reveal their true constitution. 



"When a chloride and water act on one another, three different courses 

 are open, each giving hydrochloric acid as one of the results. In the 

 first case the chlorine combines with one of the atoms of hydrogen, 

 while the remaining hydroxy 1, HO, takes its place in the original com- 

 pound, thus : — 



P OL + SH, 0=3H Cl+P H3 O3 {pliosfiorous acid). 



In the second case two atoms of chlorine simultaneously attack the two 

 atoms of hydrogen, and the liberated single atom of oxygen takes their 

 place, thus : — 



PCl,-f H,0 = 2HCH-P CI3O {pxyclihride of pTiospliorus). 



In each of these cases we may consider the new compound as formed 

 on the same type as the original chloride, only the chlorine is differently 

 replaced. 



CI no 



In the one case P CI becomes P K O, 



CI HO 



Cl^j CI 

 and in the other P CI becomes P CI O. 



CI ^ CI 



