914
ANALYTICAL CHEMISTRY
118. lead Diiodate, Pb(lO,), EUGENE STARITZKY and DONALD I. W A L K E R ' The University of California, Lor Alamor Scientific Laboratory, Lo, Alamos, N. M. diiodate is prepared by adding potassium iodate to a hot L aqueous solution of lead nitrate and allowing the resulting solution to cool slowly with agitation. EAD
X-RAYDIFFRACTION DATA S ace Group. Pccn (D::) &ll Dimensions. a. = 5.60 A.; bo = 16.70 A.; co = 6.09A.; ao:b,:co = 0.335:1:0.365. Cell volume 570 A3 Formula Weights per Cell. 4. Formula Weight. 557.05. Density. 6.50 grams per cc. (x-ray); 6.50 (pycnometer). OPTICAL PROPERTIES Refractive Indices (5893 A). nx = 2.15; ny = 2.15; nz = 2.18; geometric mean 2.16. hlolecular refraction 47.1 cc. Optic Orientation. X = c; Y = b; 2 = a. Optic Axial Angle (5893 A,). 2Vz = 24' with very strong dispersion T < v . Colorless. WORKdone under t h e auspices of t h e Atomic Energy Commission.
118. Cobalt Trifluoride, COF, EUGENE STARITZKY and R. M. D O U G L A S S Tho University of California, Lo Alamos Scientific Laboratory, Lo, Alamos, N. M. crystals of cobalt trifluoride were prepared by L. B. of this laboratory by sublimation while passing fluorine gas over cobalt dichloride heated to 750" C. Cobalt trifluoride is probably isomorphous with trifluorides of aluminum, iron, palladium, and rhodium (1). UHEDRAL
A Asprey
Figure 1. Orthographic projections of a crystal of lead diiodate parallel to a and on (010)
Partial Powder X-Ray Diffraction Pattern of Pb(IO& hkl 020 131 002 012 060 151 122 062 212 260 181 123 310 242 133
d , A., Celcd. 8.35 3.313 3.045 2.996 2,783 2.595 2.548
;:E;} 1.974
1
1.862 1.860 1.855 1.848 1.805
d , A.; Obsd. 8.26
I/Ilb
1.964
40
1.851
10
1,421 1.404 1.390 1.350 1.344
D
5
5 10
5 35
a Philips 114.6-mm.-diameter powder camera, Straumanis mounting: X (CuKa) = 1.5418 A . b Relative peak intensities above background from densitometer measurements.
CRYSTAL MORPHOLOGY System and Class. Orthorhombic, dipyramidal. Axial Elements. a : b : c = 0.336:1:0.370. Habit. Blades, flattened ( O l O } , elongated [OOl], with ( l l O } , ( 130), and { 121 1. Polar Angles. (010) A (110) = 71" 25'; (010) A (121) = 63" 33 . Present address, Department of Chemistry, University of Colorado, Boulder, Colo. 1
CRYSTAL MORPHOLOGY The crystals examined were anhedral grains exhibiting cleavage or parting on a rhombohedron with an 87" angle and twinned olysynthetically with the same rhombohedron as the twinning p7ane. X-RAY DIFFRACTION DATA Space Group and Cell Dimensions. According t o Wyckoff (1) the s ace group is probably R32 (D:)and the dimensions of the dimogcular rhombohedral cell are a0 = 5.31 A,, cy = 57" 00'. The observed lines of the powder pattern, however, do not require a unit larger than a unimolecular rhombohedral cell with dimensions a0 = 3.645 A., a = 87.2" [Wyckoff (1) gives a0 = 3.671 A., 01 = 87' 20'1. The matrix of the transformation from the
d , A., d , A., Calcd. Obsd. b 3.63 3.637 2.634 2.63 110 2.514 2.51 1Oi 2,205 2.182 111 Ili 2.068 2.067 200 1.818 1.818 210 1.658 1.667 1.597 20 i 1.596 1.546 211 1.547 1.473 21 i 1.473 2ii 1.451 1.450 1.317 1.317 220 1.266 221 1.267 1.257 1.256 202 1.212 1.211 300, 22i 1.188 21% 1.187 1.1664 310 1.165 30i 1.1343 1.133 1.1305 1.131 311 222 1,1024 1.103 1.0919 1.085 31i 3ii 1 ,0740 1.073 1.0339 222 1.0312 1.0310 320 1.0099 1,0099 321 0.9876 0.9875 305 32i 0.9752 0.9749 0,9559 0,9562 312 0.9501 0,9496 3iZ 0.9234 0,9240 322 0.9092 0,9092 400 a Indices for unimolecular rhombohedral cell. b Philips 114.6-mm.-diameter powder camera, Straumanis X(CoKa) = 1.7902 A.
hkl" 100
I YYS
s m 8 W 8 V8
ms w
m m wm wm vw vvw wm W
vvw vvw VW
w vw
..
W
vvw vvw YYU'
vW VYW
vw vvw mounting:
V O L U M E 2 8 , NO. 5, M A Y 1 9 5 6 unimolecular to the dimolecular rhombohedral cell is - - 3 3 3 1 4 1 1 1 4 B / 3 ~ 3. The volume of the unimolecular rhombohedral 3 cell is 48.26 A? Formula Weight. 115.94. Density. 3.99 grams per cc. (calculated from authors' cell dimensions; weight of unit atomic weight 1.6602 X gram). OPTICALPROPERTIES Uniaxial positive. Refractive Indices (5893 A.). no = 1.703 f 0.003, n E . = 1.726 f 0.004; geometric mean 1.711. Molecular refraction 11.4 cc. Color. 0 brown, E greenish brown. LITERATURE CITED (1) Wyckoff, R. W. G., "Crystal S t r u c t u r e s , " vol. I, chap. V, pp. 12-13, t a b l e pp. 15-16, 1 9 , Interscience, New York, 1951.
WORKdone under the auspices of the Atomic Energy Commission.
915
121. Beryllium Sdfide, BeS EUGENE STARITZKY, The University of California, Los Alamos Scientific Laboratory, Los Alamor, N. M. is prepared by the reaction of beryllium B metal withsulfide hydrogen sulfide a t 900" C. ERYLLIUM
CRYSTAL MORPHOLOGY Isometric, hextetrahedral. Preparations examined consisted of anhedral grains and granular aggregates. X-RAYDIFFRACTION DATA The structure of beryllium sulfide has been determined by Zgchariasen ( 1 ) to be of the sphalerite type. Space group F43m ( E ) . Cell Dimension. a0 = 4.8624 =k 0.0005 A. Cell volume 114.96 A? Zachariasen ( 1 ) reported a0 = 4.86 A. Formula Weights per Cell. 4. Formula Weight. 41.079. Density. 2.373 grams per cc. (x-ray). -
120. Diberyllium Carbide, Be$ EUGENE STARITZKY, The University of California, Lor Alamos Scientific Laboratory, Los Alamos, N. M. carbide may be prepared by heating beryllium D metal with graphite in neutral atmosphere. IBERYLLImf
a
CRYSTAL NORPHOLOGY Isometric, hesoctahedral. Preparations examined consisted of anhedral grains and granular aggregates.
Powder X-Ray Diffraction Pattern of BeS A., d , A., Calcd. Obsd." 1/11b 2.8073 111 2.807 100 2,432 2.4312 200 31 220 1.7191 1.718 39 311 1.4661 1,466 32 1.404 222 1 ,4037 1; 400 1.2156 1.216 1.115 331 1.1155 13 420 1.0873 1.087 10 0.9924 422 0,9925 13 0.9357 333, 511 0.9358 12 0,8595 440 0.8596 7 0.8219 0.8219 18 531 600, 442 0,8104 0.8104 13 Philips 114.6-mm.-diameter powder camera, Straumanis mounting: 4 : X(CuRae) = 1.54434 A . X(CuKu) = 1.5418 A . ; X (CuRai) = 1.54050 . b Relative peak intensities above background f;om densitometer measurements. hkl
Powder X-Ray Diffraction Pattern of BezC d, A., d , A.; Calcd. Obsd. 1/11b 2.5069 2.502 98 200 2.171 1 2.1710 220 1.5351 100 1.535 311 1.3092 1.309 16 222 ,... 1.2534 .. 400 1.0860 1.0855 15 33 1 0.9959 0.9961 7 420 0.9709 2 0.9709 422 0.8863 41 0.8863 333, 511 0.8356 0.8366 11 a Philips 114.6-mm.-diameter powder camera, Straumanis mounting. X(CuKa) = 1.5418 A . ; X(CuKal) = 1.54050 .4. X(CuKuz) = 1.54434 A: b Relative peak intensities above background iiorn densitometer measurements.
hkl 111
X-RAYDIFFRACTIOX DATA The structure of beryllium carbide has been determined by Stackelberg and Quatram ( 1 ) to be of the antifluorite type. Space group Fm3m (0;). Cell Dimension. u o = 4.3420 zk 0.0005 A. Cell volume 81.86 A! Stackelberg ( 1 ) reported a0 = 4.34 A. Formula Weights per Cell. 4. Formula Weight. 30.036. Density. 2.437 grams per cc. (x-ray). OPTICALPROPERTIES Isotropic. Refractive Index (6640 A ) . 2.635 0.010, Molecular refraction 8.19 cc. Colorless. LITERATURE CITED (1) Stackelberg, (1934)
M von, Quatram, F., 2. phys. Chem. (B) 27, 6@2
W o n x done under the auspices of the Atomic Energy Commission.
OPTICALPROPERTIES Isotrouic. Refradtive Index (5893 A.). 2.275 tion 10.07 cc. Colorless.
zk
0.010. Molecular refrac-
LITERATURE CITED (1) Zachariasen,
W., 2. phys. Chem. 119, 201-13 (1926).
Won= done under the auspices of the Atomic Energy Commission.
122. Dipotassium Platinum Tetrachloride, K,PtCI, EUGENE STARITZKY, The University of California, Lor Alamos Scientific Laboratory, Lor Alamos, N. M. CRYSTAL MORPHOLOGY System and Class. Tetragonal, ditetragonal-dipyramidal. Axial Elements. The author's observations were in agreement with the axial ratio determined by Nordenskiold ( 3 ) . a : c = 1:0.4161. Transformed by the matrix (llO/T10/002) to correspond to the orientation of the primitive unit cell, this becomes a : c = 1:0.5885. Habit. { 100 1 prisms terminated by ( P O 1 } and ( 101 1 . Polar Angle. (100) A (101) = 59" 31 .
