80 CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. [bull. 167. 
about 6 per cent of the pentachloride (11 per cent of the theoretical), 
when 1 molecular weight is distilled with 8 molecular weights ammo- 
oium chloride. Couldridge 1 obtained by a similar method a maxi- 
mum yield of 10 per cent of the pentachloride (18 per cent of the the- 
oretical). As a large excess of ammonium chloride is used, much 
"phospham" is formed. A modification by Gladstone and Holmes, 2 
consisting in acting on the pentachloride with mercuric chlorainide, 
gave no better results. 
I made numerous experiments in sealed tubes at 200°-260°, using sal 
ammoniac and pentachloride in theoretical proportions. In this case 
there is no formation of "phosphain," but the yield of the desired body 
is not increased — in fact, seems to be even less than by distilling with 
an excess of ammonium chloride from an open retort. What results is a 
mixture of chloronitrides, largely crystalline, but of various degrees 
of solubility and stability toward water, of which but a very small 
portion is volatile with steam. A study of this mixture would, in 
all probability, lead to the discovery of other members of the series 
(PNC1 2 ) x . 
I finally adopted a slight modification of Gladstone's original method : 
A mixture (which need not be very intimate) of 1 part pentachloride 
and 2 parts dry ammonium chloride is rapidly heated in a tubulated 
retort (one-third filled) fitted to a receiver containing water, which is 
connected with one or two WoulfFs bottles, with water, to condense the 
small portions carried over with the escaping hydrochloric acid. The 
water in the receiver should be gently agitated occasionally in order 
to break up the crust forming on the surface. When the decomposition 
is about half finished the heating is interrupted and the hard cake of 
phospham and sal ammoniac turned over with a rod inserted through 
the tubulure; this is necessary, as it is so poor a conductor that the 
bottom of the retort melts before the upper portions of the cake are 
affected. Heating must not be continued too long, because the sub- 
liming ammonium chloride acts on the chlorides condensed in the neck 
of the retort. After cooling, the substances condensed in the neck are 
removed by scraping and injecting hot water through the tubulure. 
The yield varies considerably, according to the quantity of mixture 
taken; the less the amount, the greater the yield. I have obtained as 
high as 11.5 per cent. Practically it is not desirable to push this too 
far, and I have obtained the most satisfactory results by distilling 200 
grams of mixture at a time. The proportion of ammonium chloride 
should not be less than 2 parts; otherwise much pentachloride sublimes 
unchanged. The distillate, after washing with water, is by no means 
pure triphosphonitrilic chloride; it is a mixture of chlorides, of which 
about one-half is quite stable toward cold water, but decomposed on 
distilling with steam. During this operation nearly all the triphos- 
phonitrilic chloride, P 3 N 3 C1 6 , is deposited as a hard crust in the con- 
Jour. Chem. Soc. London, Vol. LIU, p. 399. » Ibid. [2], Vol. II, p. 227. 
