OTOKES.] 
TETUAMETAPHOSPIITMK' ACID. 
119 
iug off the ether solidifies to plates as soon as the ether is completely 
removed. The crystalline substance is much more soluble in ether than 
the chloronitride, even momentary exposure to ether-vapor causing it 
to liquefy. It dissolves in cold water to a clear solution, from which, 
in a few minutes, or sooner on warming, tetrametaphosphimic acid is 
deposited. On one occasion the flask containing the chlorhydrines 
was placed in hot water and a current of dry air passed through. 
Soine hydrochloric acid was given off, and on treatment with water 
incomplete solution occurred, a portion being converted into a sandy 
powder, which, under the microscope, was seen to consist of short, 
spindle-shaped crystals. This acid was insoluble in boiling water, and 
warm ammonia converted it without dissolving into an acicular ammo- 
nium salt, difficultly soluble in water and insoluble in an excess of 
ammonia ; nitric acid dissolved this salt, which was precipitated by 
ammonia in a bulky amorphous form like precipitated alumina, which 
quickly chauged to needles. This ammonium salt was very slowly 
attacked by hot concentrated sulphuric acid, and contained 27.9G per 
cent phosphorus and 13.28 per cent nitrogen (P : N=4 : 4.2). Lack of 
material prevented further study of this finely crystallized acid, of the 
nature of which I can form no conjecture. 
Tetrametaphosphimic acid, P 4 N 4 8 H 8 +2H 2 0. — The free acid may be 
prepared by the first method above described. It is not readily ob- 
tained pure by decomposing most of its soluble salts, as even in the 
presence of a large excess of acid more or less acid salt is deposited. 
Thus on dissolving neutral ammonium salt and adding a large excess 
of hot 5 per cent nitric acid, nearly pure acid salt was obtained. It 
may also be prepared by boiling the silver salt with much water, con- 
taining about the requisite amount of hydrochloric acid for its decom- 
position, and precipitating by further addition of the same acid to the 
filtrate. 
The analytical methods are the same as those employed for trimeta- 
phosphimates, but much longer heating with strong sulphuric acid is 
necessary because of its greater stability. 
Analyses of four air-dried preparations gave : 
Calculated for 
P 4 N 4 8 H 8+ 2H 2 0. 
Found. 
1. 
2. 
3. 
i. 
p 
35. 23 
15.94 
3.41 
35. 01 
15.93 
35. 27 
35.38 
15.99 
3. 55 
35.20 
15.92 
3.59 
N 
11 
1. P : N=4 : 4.02. 
3. P : N : H=4 : 4.06 : 12.43. From chlorhydrine. 
4. P : N : H— 4 : 4 : 12.64. First method, from aqueous portion. 
The crystal water is not given off in vacuo over sulphuric acid. At 
100° it loses weight rapidly, then slowly, but the total loss never 
