-    SILLIMANITE     -    Al2SiO5

Theoretical atomic positions and lattice parameters at experimental volum from AMCSD 

Crystal Structure 


Because of the translational symmetry all the calculations are performed in the primitive unit cell and not in the conventional unit cell. The following information regarding the structure is given with respect to this primitive unit cell, which sometimes can take an unintuitive shape.

Symmetry (experimental): 

Space group:  62  Pnma 
Lattice parameters (Å):  7.4857  7.6750  5.7751 
Angles (°):  90.0  90.0  90.0 

Symmetry (theoretical): 

Space group:  62  Pnma 
Lattice parameters (Å):  7.4921  7.7194  5.7339 
Angles (°):  90.0  90.0  90.0 

Cell contents: 

Number of atoms:  32 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Al:  0.0000  1.0000  0.0000 
Al:  0.1443  0.3476  0.2500 
Si:  0.1512  0.3426  0.7500 
O:  0.3570  0.4137  0.7500 
O:  0.3579  0.4353  0.2500 
O:  0.4814  0.0003  0.7500 
O:  0.1238  0.2261  0.5130 
Al:  0.5000  0.5000  0.0000 
Al:  0.6443  0.1524  0.7500 
Si:  0.6512  0.1574  0.2500 
O:  0.8570  0.0863  0.2500 
O:  0.8579  0.0647  0.7500 
O:  0.9814  0.4997  0.2500 
O:  0.6238  0.2739  0.4870 
Al:  0.0000  1.0000  0.5000 
Al:  0.8557  0.6524  0.7500 
Si:  0.8488  0.6574  0.2500 
O:  0.6430  0.5863  0.2500 
O:  0.6421  0.5647  0.7500 
O:  0.5186  0.9997  0.2500 
O:  0.8762  0.7739  0.0130 
Al:  0.5000  0.5000  0.5000 
Al:  0.3557  0.8476  0.2500 
Si:  0.3488  0.8426  0.7500 
O:  0.1430  0.9137  0.7500 
O:  0.1421  0.9353  0.2500 
O:  0.0186  0.5003  0.7500 
O:  0.3762  0.7261  0.9870 
O:  0.8762  0.7739  0.4870 
O:  0.3762  0.7261  0.5130 
O:  0.1238  0.2261  0.9870 
O:  0.6238  0.2739  0.0130 
Atom type 

We have listed here the reduced coordinates of all the atoms in the primitive unit cell.
It is enough to know only the position of the atoms from the assymetrical unit cell and then use the symmetry to build the whole crystal structure.

Visualization of the crystal structure: 

Size:

  
Nx:  Ny:  Nz:    
You can define the size of the supercell to be displayed in the jmol panel as integer translations along the three crys­tallo­gra­phic axis.
Please note that the structure is represented using the pri­mi­tive cell, and not the conventional one.
     

Powder Raman 

Powder Raman spectrum

The intensity of the Raman peaks is computed within the density-functional perturbation theory. The intensity depends on the temperature (for now fixed at 300K), frequency of the input laser (for now fixed at 21834 cm-1, frequency of the phonon mode and the Raman tensor. The Raman tensor represents the derivative of the dielectric tensor during the atomic displacement that corresponds to the phonon vibration. The Raman tensor is related to the polarizability of a specific phonon mode.

Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 
Choose the polarization of the lasers.
I ∥ 
I ⊥ 
I Total 

Data about the phonon modes

Frequency of the transverse (TO) and longitudinal (LO) phonon modes in the zone-center. The longitudinal modes are computed along the three cartesian directions. You can visualize the atomic displacement pattern corresponding to each phonon by clicking on the appropriate cell in the table below.

1
ac
0
0
0
0
2
ac
0
0
0
0
3
ac
0
0
0
0
4
B3u
115
116
115
115
5
A1g
140
140
140
140
1.348e+39
8.6
1.501e+38
1.0
1.498e+39
9.6
6
Au
145
145
145
145
7
B2u
145
145
145
145
8
B1g
165
165
165
165
5.475e+36
0.0
7.529e+36
0.0
1.300e+37
0.1
9
B2u
185
185
187
185
10
B1g
190
190
190
190
2.902e+36
0.0
3.991e+36
0.0
6.893e+36
0.0
11
B1u
197
197
197
202
12
B2g
202
202
202
208
1.954e+38
1.2
2.687e+38
1.7
4.642e+38
3.0
13
B3g
208
208
208
214
9.407e+37
0.6
1.293e+38
0.8
2.234e+38
1.4
14
Au
230
230
230
230
15
A1g
238
238
238
238
3.651e+39
23.3
1.763e+38
1.1
3.827e+39
24.4
16
Au
246
246
246
246
17
B1g
253
253
253
253
1.136e+37
0.1
1.561e+37
0.1
2.697e+37
0.2
18
B2g
256
256
256
256
1.847e+37
0.1
2.539e+37
0.2
4.386e+37
0.3
19
B3u
261
262
261
261
20
B3g
262
262
262
262
6.284e+36
0.0
8.641e+36
0.1
1.493e+37
0.1
21
B1u
262
265
262
262
22
B3u
269
273
269
269
23
Au
273
274
273
273
24
B1u
276
276
276
277
25
A1g
288
288
288
288
1.135e+39
7.2
1.068e+38
0.7
1.242e+39
7.9
26
B1u
299
299
299
302
27
A1g
306
306
306
306
1.481e+40
94.5
8.658e+38
5.5
1.568e+40
100.0
28
B1g
310
310
310
310
9.652e+37
0.6
1.327e+38
0.8
2.292e+38
1.5
29
Au
310
310
310
310
30
B2u
321
321
324
321
31
B3u
326
326
326
326
32
B2u
326
327
328
326
33
B2g
329
329
329
329
1.361e+38
0.9
1.871e+38
1.2
3.231e+38
2.1
34
B3u
338
339
338
338
35
Ag
357
357
357
357
2.606e+36
0.0
1.471e+36
0.0
4.078e+36
0.0
36
Ag
357
357
357
362
9.573e+37
0.6
5.404e+37
0.3
1.498e+38
1.0
37
Au
362
362
362
364
38
B3g
369
369
369
369
1.025e+38
0.7
1.409e+38
0.9
2.434e+38
1.6
39
B1g
373
373
373
373
4.887e+38
3.1
6.719e+38
4.3
1.161e+39
7.4
40
B2u
375
375
383
375
41
B2u
389
389
393
389
42
A1g
393
393
403
393
4.243e+38
2.7
6.171e+37
0.4
4.860e+38
3.1
43
B1g
403
403
404
403
1.616e+39
10.3
2.222e+39
14.2
3.838e+39
24.5
44
B3g
410
410
410
410
4.553e+36
0.0
6.260e+36
0.0
1.081e+37
0.1
45
B3u
411
415
411
411
46
B2g
415
426
415
415
2.181e+38
1.4
2.999e+38
1.9
5.180e+38
3.3
47
B2u
426
434
434
426
48
Au
434
437
437
434
49
B1g
437
439
439
437
50
A1g
439
451
451
439
6.909e+39
44.1
1.109e+39
7.1
8.018e+39
51.1
51
B1u
451
455
462
461
52
B3u
462
465
465
462
53
B2g
465
502
500
465
5.313e+38
3.4
7.305e+38
4.7
1.262e+39
8.0
54
B2u
504
504
506
504
55
B3g
506
506
524
506
1.299e+38
0.8
1.786e+38
1.1
3.085e+38
2.0
56
Au
524
524
526
524
57
B3u
526
528
528
526
58
B1u
528
532
534
567
59
B3g
567
567
567
571
1.550e+38
1.0
2.132e+38
1.4
3.682e+38
2.3
60
A1g
571
571
571
580
6.932e+39
44.2
1.242e+38
0.8
7.057e+39
45.0
61
B2u
580
580
584
586
62
B3u
586
586
586
591
63
B2u
591
591
597
596
64
B1u
597
597
598
598
65
Au
598
598
599
599
66
B3u
599
599
617
603
67
B2g
617
617
622
617
68
B1g
623
623
623
623
4.518e+37
0.3
6.213e+37
0.4
1.073e+38
0.7
69
B2g
649
649
649
649
70
Au
651
651
651
651
71
B1u
654
654
654
671
72
B3g
671
671
671
682
1.221e+39
7.8
1.679e+39
10.7
2.900e+39
18.5
73
A1g
682
682
682
683
1.581e+39
10.1
8.349e+38
5.3
2.416e+39
15.4
74
B3u
683
683
683
701
75
B2u
701
701
728
713
76
B1g
731
731
731
731
3.545e+37
0.2
4.874e+37
0.3
8.419e+37
0.5
77
B1g
740
740
740
740
1.563e+36
0.0
2.149e+36
0.0
3.712e+36
0.0
78
A1g
741
741
741
741
1.612e+38
1.0
4.004e+37
0.3
2.012e+38
1.3
79
B3u
765
769
765
765
80
B2u
769
819
792
769
81
A1g
830
830
830
830
6.236e+39
39.8
9.944e+38
6.3
7.230e+39
46.1
82
B3u
843
854
843
843
83
B2g
854
855
854
854
1.113e+38
0.7
1.530e+38
1.0
2.644e+38
1.7
84
B2u
855
857
857
855
85
Au
857
857
857
857
86
B1u
857
864
864
864
87
B3g
864
866
864
866
2.492e+39
15.9
3.427e+39
21.9
5.919e+39
37.7
88
B1g
866
881
866
905
3.313e+38
2.1
4.555e+38
2.9
7.868e+38
5.0
89
B2u
905
905
905
905
90
B3u
905
911
911
911
91
A1g
911
961
923
988
1.282e+40
81.7
5.039e+38
3.2
1.332e+40
85.0
92
B1g
988
988
988
993
6.151e+38
3.9
8.458e+38
5.4
1.461e+39
9.3
93
A1g
1094
1094
1094
1094
3.613e+39
23.0
1.309e+38
0.8
3.744e+39
23.9
94
B1g
1099
1099
1099
1099
4.168e+38
2.7
5.731e+38
3.7
9.899e+38
6.3
95
B2u
1133
1133
1141
1133
96
B3u
1141
1184
1194
1141
No.  Char.  ω TO  ω LOx  ω LOy  ω LOz  I ∥  I ⊥  I Total 
You can define the size of the supercell for the visualization of the vibration.
Nx: 
Ny: 
Nz: 
Normalized
Raw
Options for intensity.