VOLATILE CHLORIDES WITH AMMONIA. 35 
and neutral phosphite of the oxide of ammonium, has found in 
it only 4 atoms of ammonia (P/Cl?+4 N H*)*, The liquid chlo- 
ride of phosphorus, even when strongly cooled, absorbs gaseous 
ammonia with avidity; I have drawn especial attention to the 
circumstance that the combination can only be obtained pure 
when the chloride is brought into contact with the ammoniacal 
gas very slowly and with great cooling. 
I had already devoted much fruitless labour to produce a 
combination of ammonia with the solid chloride of phosphorus 
corresponding to phosphoric acid, in definite proportionyt. I 
have subsequently repeated those experiments, but with the 
same unfavourable result. I shall, however, briefly communi- 
cate the results of these later experiments. 
The solid chloride of phosphorus is heated with the greatest 
violence, when treated with dried ammoniacal gas. If, however, 
the mass, completely saturated with ammonia, when it has be- 
come much warmed, is treated with water, phosphuretted 
nitrogen remains undissolved, and in the solution no phos- 
phoric acid can be detected by reagents; it contains only 
chloride of ammonium. If, on the other hand, the solid chlo- 
ride of phosphorus is treated slowly and under great cooling 
with dried gaseous ammonia, it absorbs almost none of it; it 
can be kept for a long time in a vessel filled with ammoniacal gas 
when it is perfectly closed. When it is dissolved in water, this 
happens with evolution of great heat, as is the case with pure 
chloride of phosphorus, some flocks of undissolved phospho- 
retted nitrogen float in the solution; but it contains only phos- 
phoric and hydrochloric acids. These observations agree in 
part with those published long since by Liebig and Wéohlert. 
Protochloride of arsenic-ammonia.—I had not previously pre- 
pared this compound. Persoz states that it is composed after 
the formula As Cl? + 2.N H%§. For the experiments which I 
more recently 1 made to determine the composition of this com- 
bination, I employed a protochloride of arsenic, which had been 
partly obtained by distillation of a mixture of powdered arseni- 
ous acid, chloride of sodium and sulphuric acid, and partly by 
treating metallic arsenic with chlorine gas. The protochloride 
* Annales de Chimie et de Physique, t. xliv. p. 320. 
i Poggendorff’s Annalen, vol. xxiv. p. 311. 
{ Annalen der Pharmacie, vol. xi. p. 139. 
§ Annales de Chimie et de Physique, t. xliv. p. 520. 
D2 
