Institute of Experimental Mineralogy
Russian Academy of Sciences
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142432, Chernogolovka, Moscow district
A.V. Chichagov +7(496)52-22320
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*** W W W - X R A Y P O L ***
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MAGNESIOCHROMITE
1, t-spinel, f-oxospinelides, sf-spinel, s-chromite
MgCr(2)O(4)
Cubic F d3m Z = 8
Fd3m
17 .4 .1992
Ref.Str.:
1. Smyth J.R., Bish D.L. (1988)
* Crystal structures and cation sites of the rock-forming
minerals.Boston.
2. Hill R.J.,Craig J.R., Gibbs G.V. (1979)
* Phys. Chem. Minerals, 4, 317-339
3. Yamanaka T., Takeuchi Y., Tokonami M. (1984)
* Acta Cryst., B 40, 96-102
Initial data from BDM-file
Lattice parameters (cub. angs.,degr.):
a = 8.333 alpha = 90.0
b = 8.333 beta = 90.0
c = 8.333 gamma = 90.0
Unit cell volume (cub. angs.) = 578.63
Molar volume ( cub.cm/mol.) = 43.57
Co-ordinates, thermal parameters, occupation for atomic positions:
NoP x/a y/b z/c B(j) atom / occupation
1 0.625 0.625 0.625 0.56 Cr = 1.00
2 0.0 0.0 0.0 0.61 Mg = 1.00
3 0.3873 0.3873 0.3873 0.85 O = 1.00
Co-ordinates for all atomic positions :
No NoP x/a y/b z/c
1 1 0.625 0.625 0.625
2 2 0.0 0.0 0.0
3 3 0.3873 0.3873 0.3873
4 1 0.125 0.375 0.875
5 1 0.375 0.875 0.125
6 1 0.875 0.125 0.375
7 2 0.75 0.75 0.25
8 2 0.0 0.5 0.5
9 2 0.25 0.75 0.75
10 3 0.3627 0.1373 0.6373
11 3 0.6127 0.1127 0.8873
12 3 0.6373 0.3627 0.1373
13 1 0.125 0.875 0.375
14 1 0.875 0.375 0.125
15 1 0.375 0.125 0.875
16 2 0.75 0.25 0.75
17 2 0.5 0.0 0.5
18 3 0.3627 0.6373 0.1373
19 3 0.1127 0.6127 0.8873
20 3 0.1373 0.3627 0.6373
21 1 0.375 0.375 0.625
22 1 0.375 0.625 0.375
23 1 0.125 0.625 0.125
24 1 0.875 0.625 0.875
25 1 0.125 0.125 0.625
26 1 0.625 0.375 0.375
27 1 0.625 0.125 0.125
28 1 0.625 0.875 0.875
29 1 0.875 0.875 0.625
30 2 0.25 0.25 0.25
31 2 0.5 0.5 0.0
32 3 0.6127 0.6127 0.3873
33 3 0.1373 0.8627 0.1373
34 3 0.8873 0.3873 0.8873
35 3 0.6373 0.8627 0.6373
36 3 0.8873 0.8873 0.3873
37 3 0.8627 0.1373 0.1373
38 3 0.3873 0.8873 0.8873
39 3 0.8627 0.6373 0.6373
40 3 0.1127 0.1127 0.3873
41 3 0.3873 0.6127 0.6127
42 3 0.6127 0.3873 0.6127
43 3 0.1373 0.6373 0.3627
44 3 0.8627 0.3627 0.3627
45 3 0.1127 0.3873 0.1127
46 3 0.8873 0.6127 0.1127
47 3 0.3627 0.3627 0.8627
48 3 0.6373 0.6373 0.8627
49 3 0.6127 0.8873 0.1127
50 3 0.3873 0.1127 0.1127
51 3 0.3627 0.8627 0.3627
52 3 0.6373 0.1373 0.3627
53 3 0.8627 0.8627 0.8627
54 3 0.1373 0.1373 0.8627
55 3 0.8873 0.1127 0.6127
56 3 0.1127 0.8873 0.6127
X-ray density (g/cm cub.) = 4.41
MU (1/cm) = 968.658 Mass attenuation coefficient (cm**2/g) = 219.489
Selected interatomic distances (cation-anion,anion-anion):
NoP Atom Rad.sph. C.N. Distance NoP N.
(angs.) (angs.)
1 Cr 2.628 6
1.9861 3
1.9861 3
1.9861 3
1.9861 3
1.9861 3
1.9861 3
2 Mg 2.52 4
1.9817 3
1.9817 3
1.9817 3
1.9817 3
3 O 3.264 12
2.9533 3
2.9533 3
2.9533 3
2.9533 3
2.6563 3
3.2361 3
2.6563 3
2.6563 3
2.9533 3
3.2361 3
3.2361 3
2.9533 3
X-ray diffraction powder data (II), X-Ray W.L. = 1.78892(angs.):
No H K L Theta 2*Theta S LPG MF F I int.
( degree ) *100
1 1 1 1 10.715 21.429 0.104 54.96 8 140.0 2575.6
2 2 2 0 17.674 35.348 0.17 18.96 12 76.6 398.7
3 1 1 3 20.855 41.71 0.199 13.15 24 184.5 3207.7
4 2 2 2 21.829 43.658 0.208 11.87 8 117.6 392.6
5 4 0 0 25.427 50.854 0.24 8.4 6 342.5 1765.5
6 3 3 1 27.897 55.794 0.262 6.8 24 55.7 151.5
7 4 2 0 28.688 57.376 0.268 6.38 24 0.0 0.0
8 2 2 4 31.726 63.451 0.294 5.1 24 54.4 108.1
9 1 1 5 33.901 67.801 0.312 4.43 24 179.7 1024.7
10 3 3 3 33.901 67.801 0.312 4.43 8 111.0 130.3
11 4 4 0 37.388 74.775 0.339 3.65 12 353.8 1637.3
12 5 3 1 39.422 78.844 0.355 3.33 48 75.0 268.5
13 4 4 2 40.094 80.187 0.36 3.24 24 8.9 1.8
14 6 2 0 42.756 85.512 0.379 2.97 24 41.0 35.8
15 3 3 5 44.738 89.477 0.393 2.84 24 121.5 300.8
X-ray diffraction powder data (I)...X-Ray wave length = 1.78892 (angs.):
No H K L Theta 2*Theta d I int I int.n. I p.h.n. H(Si)
( degree ) (angstrem) *100 *100
1 1 1 1 10.715 21.429 4.81106 2575.6 80.3 81.7 5.6
2 2 2 0 17.674 35.348 2.94616 398.7 12.4 12.5 5.7
3 1 1 3 20.855 41.71 2.51249 3207.7 100.0 100.0 5.7
4 2 2 2 21.829 43.658 2.40553 392.6 12.2 12.2 5.7
5 4 0 0 25.427 50.854 2.08325 1765.5 55.0 54.5 5.8
6 3 3 1 27.897 55.794 1.91172 151.5 4.7 4.6 5.8
7 2 2 4 31.726 63.451 1.70097 108.1 3.4 3.3 5.9
8 1 1 5 33.901 67.801 1.60369 1155.1 36.0 34.8 5.9
9 4 4 0 37.388 74.775 1.47308 1637.3 51.0 48.6 6.0
10 5 3 1 39.422 78.844 1.40853 268.5 8.4 7.9 6.0
11 6 2 0 42.756 85.512 1.31756 35.8 1.1 1.0 6.1
12 3 3 5 44.738 89.477 1.27077 300.8 9.4 8.6 6.2
Reference:
Chichagov A.V. et al.
Information-Calculating System on Crystal Structure Data of Minerals
(MINCRYST)
- Kristallographiya, v.35, n.3, 1990, p.610-616 (in Russian)
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