STOKES.] 
HIGHER METAPHOSPHIMIC ACIDS. 
145 
completely precipitated, provided a sufficient excess of silver nitrate 
be used. The preparations analyzed were made by preeipita ting a solu- 
tion of 1 gram sodium salt in 50 cubic centimeters water with 55 cubic 
centimeters one-fifth normal silver nitrate solution. To the sodium 
salt was added enough nitric acid to produce a salt of known compo- 
sition. Under these conditions it was found that a salt with 4 atoms 
of sodium gives very nearly the normal salt, IV^OioII^Ag;, (analyses 
3, 4, 6), the number of equivalents of silver in the precipitate always 
exceeding the number of equivalents of sodium. Up to 5 atoms of 
silver the precipitates are white ; with more silver they become more 
and more yellow in proportion to the amount of silver they contain. 
An excess of 0.3 atom over the normal imparts a perceptible yellow 
tint. The salts are unaffected by light or by heating at 100°, and are 
decomposed by cold caustic alkalies 1 with separation of silver oxide. 
In the following table the molecular formulas given are based on the 
ratio of phosphorus to silver actually determined and referred to the 
acids P5K 5 O 10 Ll 10 and PsHsOnH^. A comparison shows that the salts 
are derivatives of the former, a true metaphosphimic acid. The salts 
were dried at 100°. 
Ratio P : N : Ag. 
P. 
N. 
Ag- 
1 
f P5N5OuH6.s2Ag5.i8 
5 : 5.02 : 5. 18| P5N5O10H4.g2Ag5.i8 
16. 03 
16.34 
16.31 
15. 79 
16. 09 
16.04 
16. 45 
16.77 
16. 75 
16. 45 
16.77 
16.77 
16. 09 
16.40 
16. 32 
16.42 
16.74 
16.62 
7.26 
7. 39 
57.80 
58. 88 
[ Found 
7.41 58.7(5 
7.15 ; 58.45 
7.28 1 59.55 
7.35 ! 59.37 
2 
f P s N 6 OiiH 6 . 68 Ag5.3 3 ...*- 
5 : 5. 06 : 5. 321 P5N5O10H4.6sAg5.32 
1 Found 
3 
| P5N5OnH7.a5Ag4.95 
5 : 5. 04 : 4. 9o| P.-.NrAuHvo.A^.,-, 
( Found 
7.45 
7. 59 
7. 64 
7. 15 
7.59 
7.53 
7.28 
7.42 
7. 15 
7.43 
7.57 
7.59 
56. 66 
57.77 
57.69 
51 i. 60 
57. 77 
57. 82 
57.65 
58. 75 
58.46 
56. 78 
57.89 
57.51 
4 
( P5N5O.1H7.04Ag4.96 
5 : 4. 96 : 4. 9c| P5N5O10H5.04Ag4.96 
( Fouud 
5 
6 
[ P 6 Nr,OiiH6.85Ag5.|>i 
5 : 5. 04 : 5. 15 P 6 N 5 O 10 H4.85Ag5.i f 
f P5N5OnH7.03Ag4.97 
5 : 5. 05 : 4. 97] P5N5O10H5.03Ag4.97 
1 Found. 
Tri- and tetrametaphosphimic acids, when precipitated from ammo- 
iacal solution by excess of silver nitrate, gave amorphous yellow salts 
•PsNjOsHaAgs is scarcely affected by boiling with strong caustic potash and P 4 N 4 8 H 4 Ag 4 is 
i arcely affected in the cold, but is at onco decomposed on boiling. 
Bull. 167 10 
