X-Ray Powder Data and Unit Cell Parameters of MgBr,*GH,O Charles A. Sorrell' and Roy R. Ramey Department of Ceramic Engineering, University of Missouri, Rolla, Mo. 6540 1 Table I. Continued Detailed X-ray powder data for MgBrz.6HzO were obtained by diffractometry by use of CUK, radiation at 22°C. The data were indexed on a bimolecular monoclinic unit cell, space group C2/m, with B = 10.290 0.001 A; b = 7.334 0.001 A; c = 6.211 f 0.001 A: B = 93" 25' f 10'. Calculated density was 2.074 g/cm3, compared with a measured density of 2.07 f 0.01 g/ cm3.
*
hkl
222
*
420. 003 402 42i 330
The structure of magnesium bromide hexahydrate, M ~ C I Z . G H ~ Owas , determined by Andress and Gundermann ( 7 ) , who reported a bimolecular unit cell, space group C2/m, with a = 10.25 f 0.03 A; b = 7.40 f 0.03 A; c = 6.30 f 0.03 A; p = 93" 30' f 20'. The only available X-ray powder data appeared in the original Hanawalt compilation (2) and were subsequently included in the "Powder Diffraction File" (3). As was the case with magnesium chloride hexahydrate ( 4 ) , the data are not complete, and calculation of interplanar spacings, by use of the available unit cell parameters, indicates relatively low precision.
421 203 113 402
33i 13% 132 511 040 023 422. 313 041 223 240 512 6000 422 332 313
X-ray Procedures Powder data were acquired at 22°C by conventional methods, with a General Electric XRD-700 recording diffractometer with CUK, radiation generated at 50 kVp and 20 mA. Flat recessed sample holders, machined from
' To whom CorresDondence should be addressed. Table 1. X-Ray Powder Diffraction Data for MgBr2.6H20at 22°C
-
hkl
001 110 200 iii
1110 20ia 201 020a 021 002 220a 31i.
112
1
202 'I 2214 311 112 221 202 400 401"
022401a 312 i3i 131~
2 Bobs
dobs
14.285 14.84 17.265 20.29 21.01 21.80 23.13 24.270 28.27
6.2000 5.9693 5.1360 4.3766 4.2282 4.0761 3.8452 3.6671 3.1567
28.78
3.1019
29.94 31.55 32.08
2.9843 2.8356 2.7900
32.92
2.724
33.78 34.68 34.94 37.085
2.6539 2.5865 2.5679 2.4244
37.96
2.3702
38.745 39.99 40.43 40.84
2.3243 2.2545 2.2309 2.2095
1/11
dcalc
6.2000 5.9687 5.1359 4.3763 4.2274 4.0763 3.8442 3.6670 3.1563
i
3*1025 3.1000 2.9844 2.8365 2.7909 2.7269 2.7262 2.7164 2.7129 2.6534 2.5867 2.5679 2.4241 2.3674 2.3240 2.2546 2.2308 2.2103
6oi
23 1 8 1 100 48 2 51 16
223 24ia 403 241 332 512. 601 042 530 133. 403 620 0044 133 53i
71 62 26 58 95
607
4 2 1 15
62z 24 2 114 423 204 531 242
19 31 1
