132 
CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. [bull. 167. 
Hexaphosphonitrilic chloride, P 6 N 6 Cli 2 . — After repeated crystalliza- 
tion from benzene, 1 this gave: 
Calculated 
for 
r 6 N 6 ci 12 . 
Found. 
p 
26.75 
12.11 
61.14 
26.98 
12.37 
60.98 
N 
CI 
P :N : Cl = l : 1.01 : 1.98. 
Molecular weight. {Solvent, benzene.) 
Grams 
solvent. 
- 
Grams 
substances. 
Elevation 
(degrees). 
Molecular 
weight. 
Percentage 
variation 
from 
theoretical. 
47.12 
1. 8058 
0.152 
673 
—3.2 
47.12 
3.6190 
.293 
700 
+0.6 
45.72 
1.0101 
.083 
711 
+2.1 
45.72 
4. 4898 
.365 
718 
+3.2 
45. 72 
8. 0070 
.664 
704 
+1.2 
Calculated for P 6 N 6 Cli 2 , 695 8. 
Hexaphosphonitrilic chloride fuaes at 90° (corrected), and boils at 
261°-263° (corrected) at 13 millimeters, and at 281°-282° (corrected) al 
26 millimeters. It may be recrystallized from benzene, ii 
which, however, it is more soluble than triphosphonitrilic 
chloride; ether, gasoline, and carbon disulphide also dis 
solve it readily; in alcohol it dissolves somewhat slowly 
with decomposition. It shows no tendency to superfu 
sion. It crystallizes well, in rather large crystals, whicl 
were examined by Mr. Wirt Tassin, to whom I am in 
debted for the following statement: 
"P 6 N 6 01i2 crystallizes in the orthorhombic system in 
long, prismatic crystals, showing the following forms 
c (001), b (010), m (110), o (111), n (011). Of these c is th 
dominant form; b large and well developed; m fail 
though usually narrow, and o and n small and usually in similar deve I 
opment. c, &, m, o is the combination occurring most frequently; lesJ 
often c, b, m, n, o; and rarely c, 1), m. Angles m : m 57° 28 ; , b : m (31° 16 ,! 
b: n ^O ^^, n: c 49° 37'. Axial ratio a : b : c = 0.54824 : 1 : 1.1756* I 
The crystals are optically positive. Plane of the optic axes (100 ; 
Fig. 7. 
1 A contamination with P 6 N 7 C1 9 may be detected by treatment with gasoline, when tbe mm i 
smaller crystals of the latter are seen to dissolve much more slowly. 
