CRYSTALLOGRAPHIC DATA
129. Uranium Monochlorotrifluoride, UCIF, EUGENE STARITZKYand R. M. D O U G L A S S The Univenity of California, Lor Alamor Scientific Laboratory, Lor Alamor,
C
N. M.
of uranium monochlorotrifluoride were prepared by A. W. Savage of this laboratory by four different methods
3. By heating uranium tetrafluoride with uranium tetrachloride in a neutral atmosphere. 4. By heating uranium tetrafluoride with carbon tetrachloride in a neutral atmosphere.
1. By the reaction of uranium trifluoride with chlorine at 350' C. This method was used by Warf and others ( I ) , who described the product as isometric on the basis of powder x-ray diffraction patterns. Although the symmetry of this compound is orthorhombic, it is so nearly isometric metrically that powder xray diffraction patterns can be interpreted on the basis of a simple isometric unit cell. ) carbon 2. By the reaction of uranyl fluoride ( U O Z F ~with tetrachloride at 450' C. This method was used by Gates and others ( I ) , who assumed the reaction products to be uranium dichlorodifluoride (UCl,F,), carbonyl chloride (COCL), and chlorine. Considerations of crystal chemistry preclude the possibility that the principal solid product of this reaction is uranium dichlorodifluoride.
None of these methods yielded a product consisting of a single crystalline phase. A4nanalysis of a product of the reaction of uranyl fluoride x i t h carbon tetrachloride, estimated to contain 95% uranium inonochlorotrifluoride, gave (by weight) 70.6% uranium, 10.7% chlorine and 20.3% fluorine. This corresponds to the atomic ratio U:Cl:F = 1:1.01:3.60.
RYSTALS
(8).
CRYSTAL MORPHOLOQY System and Class. Orthorhombic, dipyramidal. Habit. Tabular (001) or dipyramidal 1111) qTith (001) and
(loo}.
Polar Angles. (111.) A (.loo) = 531/z0 (measured), 54' 44' (calculated from cell dimensions); (111) A (001) = 52l/zo (measured), 54' 44' (calculated). X-RAYDIFFRSCTIOX DATA Diffraction Symbol. mmntdbu-, embracing space groups A b a n (D$)and Sbu2 (Ciz). Cell Dlmenslons (from Calibrated Weissenberg and Precession 0.002 A., bo = 8.690 rt 0.01 A,, Photographs). uo = 8.673 =I= co = 8.663 rt 0.005 A , ; u:b:c = 0.998:1:0.997. Cell volume 652.9 A3. Formula Weights per Cell. 8. Formula Weight. 330.53. Density. 6.72 grams per cc. (calculated from cell dimensions; gram). weight of unit atomic weight 1.6602 X ~~
Ahsorption Spectrum (Rand maxima in milliniicrons and relative intensities as viewed with Zeias prism microspectronietric eyepiece) Parallel to X Parallel to Y and Z 660 very strong 676 strong 663 weak 655 weak 645 weak 650 very strong 638 strong 640 strong 633 weak 630 medium strong 620 strong 590-620 medium 608 weak 583 medium strong 522-538 ,weak 531 medium strong 527 medium strong 522 medium 495 weak 495 medium, wide 470 weak 470 medium, wide
//T\\
Partial Powder X-Ray Diffraction Pattern
ha
+ kz 43
4
5 6 8 9 11 12 13 14 16 17 18 19 20 21 22 24 25 26 27 29 30 32 33 34 35 36 37 38 40 41 42 43 44
12
d , A . , Calcd. 5,009 4.331-4.345 3.885 3.541 3,06+3,069 2.892 2.613-2.619 2 504 2.407 2.317-2.321 2.166-2.173 2,104-2.107 2.044 1.989-1.991 1.938-1.942 1.892-1.895 1.850 1,770-1.772 1,737 1.700-1.702 1,668-1.672 1.610-1.612 1.582-1.586 1.532-1.535 1.510 1.488 1.466-1.468
1.444-1.448 1.429 1.407-1.408 1.370-1.374 1.355-1.357 1.337-1.340 1.323-1.324 1.306-1.309
d , A , , Obsd.'
I/I,b
4.95 4.30 3.85 3.52 3.05 2.88 2.00
5 100
...
40
65 70 45 20
.. , .
2.3i 2.16 2.09 2.04 1,984 1.933 1.885 l:+fij
C
I
..
10
11697
55
1,664 1,606
30 3
1,579
25
1 io0
: : 1,444
3.5
1 463
4.5 30
1.430 1.403 1.368 1.353 1.336 1.320 1.305
a
45
40 35 70 95 45 80
C3 5
30 30 30 65 20
Figure 1. Orthographic projection of crystal of uranium monochlorotrifluoride on (100) and (001)
1210
V O L U M E 28, NO. 7, J U L Y 1 9 5 6
1211
OPTICALPROPERTIES Refractive Indices (5893 A
