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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SELLAITE
1
MgF(2)
Tetragonal P 4(2)/mnm Z = 2
P4(2)/mnm
29 .5 .1992
Ref.Str.:
Wyckoff R.W.G. (1963)
* Crystal Structures, 1, 250-252
Initial data from BDM-file
Lattice parameters (cub. angs.,degr.):
a = 4.623 alpha = 90.0
b = 4.623 beta = 90.0
c = 3.052 gamma = 90.0
Unit cell volume (cub. angs.) = 65.23
Molar volume ( cub.cm/mol.) = 19.64
Co-ordinates, thermal parameters, occupation for atomic positions:
NoP x/a y/b z/c B(j) atom / occupation
1 0.0 0.0 0.0 0.0 Mg = 1.00
2 0.303 0.303 0.0 0.0 F = 1.00
Co-ordinates for all atomic positions :
No NoP x/a y/b z/c
1 1 0.0 0.0 0.0
2 2 0.303 0.303 0.0
3 2 0.697 0.697 0.0
4 1 0.5 0.5 0.5
5 2 0.197 0.803 0.5
6 2 0.803 0.197 0.5
X-ray density (g/cm cub.) = 3.17
MU (1/cm) = 79.468 Mass attenuation coefficient (cm**2/g) = 25.061
Selected interatomic distances (cation-anion,anion-anion):
NoP Atom Rad.sph. C.N. Distance NoP N.
(angs.) (angs.)
1 Mg 2.484 6
1.981 2
1.981 2
1.9969 2
1.9969 2
1.9969 2
1.9969 2
2 F 3.192 11
3.052 2
3.052 2
2.5759 2
2.8128 2
2.8128 2
2.8128 2
2.8128 2
2.8128 2
2.8128 2
2.8128 2
2.8128 2
X-ray diffraction powder data (II), X-Ray W.L. = 1.54056(angs.):
No H K L Theta 2*Theta S LPG MF F I int.
( degree ) *100
1 1 1 0 13.629 27.258 0.153 33.18 4 22.5 1574.3
2 1 0 1 17.603 35.207 0.196 19.13 8 9.0 288.6
3 2 0 0 19.465 38.931 0.216 15.33 4 3.1 13.5
4 1 1 1 20.199 40.398 0.224 14.12 8 22.7 1372.3
5 2 1 0 21.874 43.749 0.242 11.81 8 14.2 445.2
6 2 1 1 26.744 53.488 0.292 7.49 16 20.9 1225.2
7 2 2 0 28.117 56.234 0.306 6.68 4 27.6 477.8
8 0 0 2 30.316 60.632 0.328 5.64 2 33.5 297.1
9 3 1 0 31.796 63.592 0.342 5.08 8 9.2 81.0
10 2 2 1 32.317 64.633 0.347 4.9 8 6.8 42.9
11 1 1 2 33.853 67.706 0.362 4.44 8 15.5 201.3
12 3 0 1 34.053 68.106 0.363 4.38 8 28.0 645.2
13 3 1 1 35.748 71.496 0.379 3.97 16 8.3 103.5
14 3 2 0 36.924 73.848 0.39 3.73 8 5.3 19.6
15 2 0 2 37.218 74.436 0.393 3.68 8 0.6 0.3
16 2 1 2 38.857 77.714 0.407 3.41 16 8.8 98.8
17 3 2 1 40.664 81.327 0.423 3.18 16 2.7 8.5
18 4 0 0 41.796 83.591 0.433 3.06 4 15.3 67.0
19 4 1 0 43.392 86.784 0.446 2.93 8 12.4 84.9
20 2 2 2 43.675 87.351 0.448 2.91 8 19.9 216.2
21 3 3 0 44.984 89.967 0.459 2.83 4 20.6 112.7
X-ray diffraction powder data (I)...X-Ray wave length = 1.54056 (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 0 13.629 27.258 3.26895 1574.3 100.0 100.0 5.6
2 1 0 1 17.603 35.207 2.54702 288.6 18.3 18.2 5.7
3 1 1 1 20.199 40.398 2.23085 1372.3 87.2 86.2 5.7
4 2 1 0 21.874 43.749 2.06747 445.2 28.3 27.9 5.7
5 2 1 1 26.744 53.488 1.7117 1225.2 77.8 75.8 5.8
6 2 2 0 28.117 56.234 1.63448 477.8 30.4 29.4 5.8
7 0 0 2 30.316 60.632 1.526 297.1 18.9 18.2 5.8
8 3 1 0 31.796 63.592 1.46192 81.0 5.1 4.9 5.9
9 2 2 1 32.317 64.633 1.44086 42.9 2.7 2.6 5.9
10 1 1 2 33.853 67.706 1.38276 201.3 12.8 12.2 5.9
11 3 0 1 34.053 68.106 1.3756 645.2 41.0 39.0 5.9
12 3 1 1 35.748 71.496 1.31847 103.5 6.6 6.2 5.9
13 3 2 0 36.924 73.848 1.28219 19.6 1.2 1.2 6.0
14 2 1 2 38.857 77.714 1.22778 98.8 6.3 5.9 6.0
15 4 0 0 41.796 83.591 1.15575 67.0 4.3 3.9 6.1
16 4 1 0 43.392 86.784 1.12124 84.9 5.4 4.9 6.1
17 2 2 2 43.675 87.351 1.11542 216.2 13.7 12.5 6.2
18 3 3 0 44.984 89.967 1.08965 112.7 7.2 6.5 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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