ANALYTICAL CHEMISTRY
934
room),, which is a standardization of the meter circuit. The meter IR Bet for the range from 0 to 100 mw. per square foot, the shutter i8 oDened.. and the lieht intensitv is adiusted bv means
known amounts of mercury in 250 ml. of water through the complete procedure. ACKNOWLEDGMENT
Thanks are here extended to Warren Ksmm and Howard MoKinney for assembling the apparatus and preparing the curves. pa.d--!iaidinf? I r k pleated by mean8 of'tbe movablefurnace, and
LITERATURE ClTED
(1) Ballard and Thornton, IND.ENO.C~EM., ANAL. ED., 13, 893
(1941).
The
CI'PVCS
given in. Piqures 2 and 3 were obtained by taking
RECEIVED January 16, 1950. Communication 1310 from the Kodsk Research Laboratories.
32* B.BX (Cyc1otsi.methylenetrinitrarnine) Contr5,loixtsrl 5 y ?VA?,TE!$ C MCCROWF, Armour Research Foundation, Illinois Institute of Technology, Chicago 16, 111.
CH,
/\
d 2 25 2 20 2 12 2 08
I/Il Very weak Very weak 0 04 0 04
-
I/Ii 0.07
d 2.01 1.97 1.92 1.86
0.09 Very weak 0.07
.
Structural Fornula for RDX
"-
DX is the symbol for the high explosive cyclotrimethylenetrinitrsmine, which was developed for u ~ eduring World
War 11. It can be crystdliaed from a variety of solvents includiiig benzene, nitrometlmne, acetone, acetic acid, and nitric acid. It possesses one very unstable polymorphic form (II), which e m be isohted only in small quantities for a few seconds during fusion
studies on a xdcroscope slide. Becmsuse of ita physical instability, there is no possibility of.obtaining RDX I1 even in laboratory recrystallisations. EDX (1)
CRYSTAL MORPHOLOGY Crystal System. Orthorhombic. Form and Habit. RDX crystallizes in 8 wide variety of habits from needles (nitric acid) and plates (acetic acid) to massive (nitromethane acetone). Usually flattened on 001 showing theforms: (1101, (1201, 11011, {.Olll,md (1111. Axial Ratio. a:b:c = 0.881:1:0.813. Interfacid .Angles (Polar). 1104 110 = 32'50'; 1 2 0 A D O = 590; 101 A io1 = 850 30'; 011 n 011 = 780 20'. X-RAYDIFFRACTTOE DATA Cell Dim~ensions. a. = 11.61. A; h = 13.19 A,; e = 10.72 A. Fomula Wejshts per Cell. 3. Parmula Weight.. 222.13. i3nnsity. ?.?2 (pyoiomster); 1.81 (x-ray).
c
d
Figure 1. Photomicrographs of RDX
V O L U M E 22, NO. 7, J U L Y 1 9 5 0 a
955 The melt solidifies spontaneously and rapidly ~ i t hlarge gas bubbles showing a terracelike structure. Many of the larger areas of uniform orientation show an off-center arute birer interference figure with 2E = 113", 2 H = 67" I ' characteristic of R D X (11). Usually, honevv~, 1 pears showing centered acute bisectrix or off-cwitoi 'll)ric i figures with 2E = 92', 2V = 53", r > ii ( - j.
a
I
I
j
RDX (11)
Figure 2. Orthoof graphic Typical Projection Crystal
b - > +
