78 CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. [bull. 167. 
Later, Wichelhaus l confirmed the results of Gladstone and Holmes, 
and suggested the structural formula 
NPC1 3 
C1 2 PN— NPC1 2 
and A. W. Hofmann 2 and Oouldridge 3 added some further observations. 
By distilling under diminished pressure the reaction product of 
phosphorus pentachloride and ammonia gas Besson 4 obtained a sub- 
stance of the composition PNC1 2 , which he describes as "un corps 
solide donnent par sublimation des cristaux tres reTringents, fusibles a 
10G°." The low melting point would indicate a body other than P 3 N 3 C1 6 
(melting point 114°), but as the latter is the chief volatile product 
formed under ordinary circumstances it may be regarded as an open 
question whether Besson's compound is identical with Liebig's. 
Finally, White 5 and Gilpin 6 observed it as a secondary product of 
the action of phosphorus pentachloride on acid ammonium orthosul- 
phobenzoate, doubtless originating in the action of the ammonia. 
None of these investigations have thrown much light on the consti- 
tution of the chlorophosphuret or on its relation to other phosphorus 
compounds. 
My attention being called to this substance while engaged in study- 
ing the amides of phosphoric acid, I have prepared it in large quantity 
with a view to further investigation. Although the experiments have 
not progressed far enough to establish any definite constitutional for- 
mula, they show that the chlorophosphuret is by no means as intracta- 
ble as has been supposed, and that it is one of an homologous series 
of compounds having the general formula (PNG1 2 ) X , which are the chlo- 
rides of an homologous series of acids (PN0 2 H 2 ) x , the metaphosphimic 
acids. From the reaction product of phosphorus pentachloride and 
ammonium chloride I have thus far isolated the body (PN01 2 ) 4 , which 
almost equals (PNC1 2 ) 3 in stability, and which yields, on saponification, 
an acid (PN0 2 H 2 ) 4 , also an extremely stable substance. A further 
product of the reaction is a stable, oily chloride (PNC1 2 ) X of high, but 
as yet unknown, molecular weight. I have also obtained from Liebig's 
chlorophosphuret the corresponding acid (PN0 2 H 2 ) 3 , an intermediate 
chlorhydrine P 3 N 3 C1 4 2 H 2 , and a chloramide P 3 N 3 G1 4 (KH 2 ) 2 . The 
object of the present paper is mainly to describe the preparation and 
properties of the chlorides, the consideration of the acids being de- 
ferred to a later occasion. 
Nomenclature. — In view of the large number of phosphorus-nitrogen 
compounds actually known or theoretically possible, it is desirable to 
have a more definite nomenclature than has thus far been used. I 
•Ber. Deutsch. chem. Gesell., Berlin, Vol. Ill, 1870, p. 163. * Compt. rend., Vol. CXIV, 1892, pp. 1264, 1480. 
'Ibid. Vol. XVII, 1884, p. 1910. s Dissertation, Baltimore, 1891, p. 13. 
8 Jour. Chem. Soe. London, Vol. LIII, 1 888, p. 398. 6 Dissertation, Baltimore, 1892, pp. 7, 16. 
