-    MALLADRITE     -    Na2SiF6

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) starting from an experimental structure similar to the one reported in 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:  150  321 
Lattice parameters (Å):  8.8590  8.8590  5.0380 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  150  321 
Lattice parameters (Å):  8.6167  8.6167  4.8388 
Angles (°):  90.0  90.0  120.0 

Cell contents: 

Number of atoms:  27 
Number of atom types:  3 
Chemical composition:  0 

Atomic positions (theoretical):

Na:  0.3736  0.3736  0.0000 
Na:  0.7083  0.7083  0.5000 
Si:  0.0000  0.0000  0.0000 
Si:  0.3333  0.6667  0.5051 
F:  0.0858  0.9012  0.8021 
F:  0.4438  0.5942  0.7053 
F:  0.2255  0.7426  0.3052 
Na:  0.0000  0.6264  0.0000 
Na:  0.0000  0.2917  0.5000 
F:  0.8154  0.9142  0.8021 
F:  0.1504  0.5562  0.7053 
F:  0.5171  0.7745  0.3052 
Si:  0.6667  0.3333  0.4949 
F:  0.9012  0.0858  0.1979 
F:  0.5942  0.4438  0.2947 
F:  0.7426  0.2255  0.6948 
Na:  0.6264  0.0000  0.0000 
Na:  0.2917  0.0000  0.5000 
F:  0.0988  0.1846  0.8021 
F:  0.4058  0.8496  0.7053 
F:  0.2574  0.4829  0.3052 
F:  0.1846  0.0988  0.1979 
F:  0.8496  0.4058  0.2947 
F:  0.4829  0.2574  0.6948 
F:  0.9142  0.8154  0.1979 
F:  0.5562  0.1504  0.2947 
F:  0.7745  0.5171  0.6948 
Atom type  X  Y  Z 

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.

Choose the polarization of the lasers.

I ∥ 
I ⊥ 
I Total 
Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 

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
A2
43
43
43
44
5
A1
54
54
54
54
4.722e+36
0.0
1.574e+36
0.0
6.296e+36
0.0
6
E
63
63
63
63
2.849e+37
0.1
2.775e+37
0.1
5.625e+37
0.3
7
E
63
65
65
63
2.850e+37
0.1
3.064e+37
0.1
5.914e+37
0.3
8
A2
73
73
73
79
9
E
79
79
79
79
10
E
79
80
80
97
11
E
107
107
107
107
3.984e+37
0.2
3.765e+37
0.2
7.749e+37
0.4
12
E
107
112
112
107
3.984e+37
0.2
6.632e+37
0.3
1.062e+38
0.5
13
E
128
128
128
128
6.267e+36
0.0
6.014e+36
0.0
1.228e+37
0.1
14
E
128
128
128
128
6.266e+36
0.0
1.046e+37
0.1
1.673e+37
0.1
15
A2
132
132
132
134
16
A1
138
138
138
138
4.723e+37
0.2
5.903e+36
0.0
5.313e+37
0.3
17
E
139
139
139
139
1.171e+37
0.1
1.247e+37
0.1
2.418e+37
0.1
18
E
139
139
139
139
1.170e+37
0.1
1.244e+37
0.1
2.414e+37
0.1
19
A2
173
173
173
174
20
E
190
190
190
190
2.070e+36
0.0
2.321e+36
0.0
4.391e+36
0.0
21
E
190
190
190
190
2.070e+36
0.0
2.211e+36
0.0
4.281e+36
0.0
22
E
199
199
199
199
1.181e+37
0.1
1.049e+37
0.1
2.231e+37
0.1
23
E
199
200
200
199
1.181e+37
0.1
1.931e+37
0.1
3.112e+37
0.1
24
E
201
201
201
201
8.700e+36
0.0
1.196e+37
0.1
2.066e+37
0.1
25
E
201
205
205
201
8.698e+36
0.0
1.196e+37
0.1
2.066e+37
0.1
26
A1
205
209
209
205
4.666e+37
0.2
7.747e+35
0.0
4.743e+37
0.2
27
E
216
216
216
216
2.598e+37
0.1
2.683e+37
0.1
5.281e+37
0.3
28
E
216
217
217
216
2.598e+37
0.1
4.381e+37
0.2
6.979e+37
0.3
29
A2
231
231
231
235
30
E
240
240
240
240
2.619e+36
0.0
1.964e+36
0.0
4.583e+36
0.0
31
E
240
241
241
240
2.618e+36
0.0
3.600e+36
0.0
6.219e+36
0.0
32
A1
241
246
246
241
6.330e+37
0.3
8.627e+36
0.0
7.192e+37
0.3
33
E
252
252
252
252
5.565e+37
0.3
7.598e+37
0.4
1.316e+38
0.6
34
E
252
254
254
252
5.565e+37
0.3
7.221e+37
0.3
1.279e+38
0.6
35
A2
254
267
267
265
36
A2
285
285
285
286
37
A1
286
286
286
288
3.800e+36
0.0
4.751e+35
0.0
4.275e+36
0.0
38
E
288
288
288
288
6.377e+37
0.3
4.783e+37
0.2
1.116e+38
0.5
39
E
288
288
288
289
6.374e+37
0.3
8.764e+37
0.4
1.514e+38
0.7
40
E
291
291
291
291
4.050e+37
0.2
3.475e+37
0.2
7.525e+37
0.4
41
E
291
296
296
291
4.054e+37
0.2
4.616e+37
0.2
8.670e+37
0.4
42
A1
298
298
298
298
4.001e+38
1.9
1.976e+38
0.9
5.976e+38
2.9
43
E
300
300
300
300
3.013e+37
0.1
2.970e+37
0.1
5.983e+37
0.3
44
E
300
304
304
300
3.012e+37
0.1
3.230e+37
0.2
6.242e+37
0.3
45
A2
304
313
313
313
46
E
396
396
396
396
1.676e+38
0.8
1.417e+38
0.7
3.093e+38
1.5
47
E
396
396
396
396
1.676e+38
0.8
2.681e+38
1.3
4.357e+38
2.1
48
E
399
399
399
399
1.458e+38
0.7
1.813e+38
0.9
3.271e+38
1.6
49
E
399
399
399
399
1.456e+38
0.7
1.631e+38
0.8
3.087e+38
1.5
50
E
406
406
406
406
1.226e+38
0.6
1.253e+38
0.6
2.480e+38
1.2
51
E
406
406
406
406
1.228e+38
0.6
1.308e+38
0.6
2.536e+38
1.2
52
A2
412
412
412
412
53
A1
413
413
413
413
4.317e+38
2.1
2.975e+38
1.4
7.292e+38
3.5
54
A1
416
416
416
416
3.407e+38
1.6
1.453e+38
0.7
4.860e+38
2.3
55
A2
453
453
453
458
56
A1
458
458
458
458
5.798e+36
0.0
1.933e+36
0.0
7.730e+36
0.0
57
A2
463
463
463
471
58
E
471
471
471
471
2.008e+38
1.0
2.025e+38
1.0
4.033e+38
1.9
59
E
471
472
472
472
2.008e+38
1.0
3.379e+38
1.6
5.386e+38
2.6
60
E
480
480
480
480
4.524e+38
2.2
6.026e+38
2.9
1.055e+39
5.1
61
E
480
480
480
480
4.523e+38
2.2
6.934e+38
3.3
1.146e+39
5.5
62
E
485
485
485
485
3.460e+38
1.7
2.628e+38
1.3
6.088e+38
2.9
63
E
485
485
485
485
3.463e+38
1.7
5.026e+38
2.4
8.488e+38
4.1
64
E
487
487
487
487
1.825e+38
0.9
1.804e+38
0.9
3.628e+38
1.7
65
E
487
496
496
487
1.824e+38
0.9
3.061e+38
1.5
4.885e+38
2.3
66
E
504
504
504
504
1.384e+38
0.7
1.902e+38
0.9
3.286e+38
1.6
67
E
504
504
504
504
1.384e+38
0.7
1.903e+38
0.9
3.287e+38
1.6
68
E
529
529
529
529
2.260e+38
1.1
2.718e+38
1.3
4.978e+38
2.4
69
E
529
532
532
529
2.260e+38
1.1
2.477e+38
1.2
4.736e+38
2.3
70
A1
646
646
646
646
2.081e+40
100.0
2.341e+36
0.0
2.081e+40
100.0
71
A2
647
647
647
647
72
A1
665
665
665
665
6.685e+39
32.1
3.964e+35
0.0
6.685e+39
32.1
73
A1
699
699
699
699
3.280e+37
0.2
9.262e+31
0.0
3.280e+37
0.2
74
A2
707
707
707
712
75
E
712
712
712
712
5.163e+37
0.2
7.099e+37
0.3
1.226e+38
0.6
76
E
712
729
729
729
5.163e+37
0.2
7.099e+37
0.3
1.226e+38
0.6
77
A2
729
768
768
768
78
E
768
768
768
768
5.022e+36
0.0
5.952e+36
0.0
1.097e+37
0.1
79
E
768
775
775
777
5.022e+36
0.0
5.462e+36
0.0
1.048e+37
0.1
80
E
777
777
777
777
7.029e+36
0.0
6.275e+36
0.0
1.330e+37
0.1
81
E
777
816
816
810
7.031e+36
0.0
1.151e+37
0.1
1.854e+37
0.1
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.