118 CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. I bull. 167. 
EXPERIMENTAL PART. 
Preparation of tetrametaphosphimic acid. — Tetraphosphonitrilie chlo- 
ride can be saponified by alcoholic alkalies, but the yield of tetraineta- 
phosphimic acid is poor, owing to the formation of ethers, which, 
however, can be decomposed by prolonged treatment. Satisfactory 
results are obtained by using an ethereal solution, which is agitated, 
in the manner described under trimetaphosphimic acid, with either 
water, ammonia, or a solution of ammonium acetate. 
Decomposition by water. — As tetrametaphosphimic acid is not per- 
ceptibly attacked by cold hydrochloric acid, water may be used when 
it is desired to obtain the free acid directly. One part P 4 N 4 C1 8 is dis- 
solved in 15 volumes alcohol free ether and gently agitated with 5 vol! 
umes water. Within half an hour needles of the free acid begin to 
separate from the aqueous portion, and after many hours the latter has 
become converted into a thick pasty mass of needles suspended in 
dilute hydrochloric acid. Ohlorhydrines are formed as intermediate 
products, and these remain dissolved in the ether. It is not necessary 
to continue the agitation until they are completely decomposed; as 
soon as a few drops of the ether leave a residue wholly soluble in 
water, the ether is decanted and the aqueous portion filtered, the 
crystals being washed with 10 per cent hydrochloric acid or alcohol. 
The ethereal portion, containing the chlorhydrines, is evaporated cau- 
tiously. The chlorhydrines which remain as an oil from which crystals 
separate after complete removal of the ether, are dissolved in a little 
cold water and warmed, with addition of dilute hydrochloric acid, in 
which tetrametaphosphimic acid is much less soluble than in pure 
water. The separation of the acid is nearly complete after a few min- 
utes. This portion is better crystallized than that obtained directly, 
but is otherwise the same. The acid may be recrystallized from hot 
water, but this is quite unnecessary. Yield, about theoretical. 
Decomposition by ammonia. — The ethereal solution of the chloroni- 
tride is shaken for a short time with aqueous ammonia. This does not 
give chloramide as is the case with P 3 N 3 C1g, but produces at once 
neutral ammonium tetrametaphosphimate, P 4 N 4 8 H 4 (NH 4 ) 4 -f4H 2 0, 
which is precipitated by adding alcohol and washed with dilute alco- 
hol. The decomposition is complete in a few minutes. 
Decomposition by ammonium acetate. — One part chloronitride, dis- 
solved in 15 volumes ether, is agitated with a solution of 4 parts 
ammonium acetate in 8 parts water. After several hours crystals 
begin to separate. The final product is a mixture of acid ammonium 
salt with some neutral salt and some free acid, and is nearly insoluble 
in the strong salt solution. It is washed with alcohol, dissolved in 
dilute ammonia, and reprecipitated by alcohol. Yield, theoretical. 
Ammonium acetate is to be preferred to sodium acetate, as the sodium 
salt does not precipitate well with alcohol. 
Chlorhydrines. — None of these were isolated. The oil left on distill- 
