-    DICKITE     -    Al2Si2O5(OH)4

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:  Cc 
Lattice parameters (Å):  5.1610  8.9600  14.4590 
Angles (°):  90  96.77  90 

Symmetry (theoretical): 

Space group:  Cc 
Lattice parameters (Å):  5.0488  5.0488  14.0523 
Angles (°):  87.05  92.94  60.06 

Cell contents: 

Number of atoms:  34 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Si:  0.4116  0.3821  0.0298 
Si:  0.0703  0.0663  0.0293 
Al:  0.1556  0.3393  0.2238 
Al:  0.8267  0.9964  0.2226 
O:  0.1730  0.2948  0.9811 
O:  0.7288  0.1844  0.9811 
O:  0.2943  0.7330  0.9977 
O:  0.4644  0.3053  0.1426 
O:  0.0793  0.0762  0.1424 
O:  0.8476  0.6889  0.1476 
O:  0.5102  0.0232  0.2887 
O:  0.1458  0.6500  0.2891 
O:  0.8834  0.2746  0.2880 
H:  0.6546  0.6902  0.1403 
H:  0.5457  0.9766  0.3581 
H:  0.3366  0.6479  0.3042 
H:  0.8716  0.2834  0.3571 
Si:  0.6179  0.5884  0.5298 
Si:  0.9337  0.9297  0.5293 
Al:  0.6607  0.8444  0.7238 
Al:  0.0036  0.1733  0.7226 
O:  0.7052  0.8270  0.4811 
O:  0.8156  0.2712  0.4811 
O:  0.2670  0.7057  0.4977 
O:  0.6947  0.5356  0.6426 
O:  0.9238  0.9207  0.6424 
O:  0.3111  0.1524  0.6476 
O:  0.9768  0.4898  0.7887 
O:  0.3500  0.8542  0.7891 
O:  0.7254  0.1166  0.7880 
H:  0.3098  0.3454  0.6403 
H:  0.0234  0.4543  0.8581 
H:  0.3521  0.6634  0.8042 
H:  0.7166  0.1284  0.8571 
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
B'
28
28
28
28
5
A'
32
32
32
33
3.452e+38
0.2
2.566e+38
0.2
6.019e+38
0.4
6
B'
119
119
120
119
6.798e+36
0.0
1.113e+37
0.0
1.792e+37
0.0
7
A'
124
124
124
125
6.434e+38
0.5
3.055e+38
0.2
9.490e+38
0.7
8
B'
125
125
125
125
6.381e+37
0.0
9.368e+37
0.1
1.575e+38
0.1
9
B'
133
133
133
133
2.432e+38
0.2
3.344e+38
0.2
5.776e+38
0.4
10
A'
134
134
134
134
8.881e+38
0.6
9.734e+38
0.7
1.861e+39
1.3
11
A'
153
154
153
163
2.663e+39
1.9
1.521e+39
1.1
4.184e+39
2.9
12
B'
166
166
168
166
1.504e+38
0.1
1.826e+38
0.1
3.330e+38
0.2
13
A'
192
192
192
192
3.968e+39
2.8
1.099e+37
0.0
3.979e+39
2.8
14
B'
193
193
193
193
3.168e+37
0.0
5.291e+37
0.0
8.458e+37
0.1
15
B'
205
205
206
205
1.411e+38
0.1
1.505e+38
0.1
2.916e+38
0.2
16
A'
206
206
206
206
1.149e+39
0.8
8.567e+38
0.6
2.005e+39
1.4
17
B'
223
223
223
223
4.562e+37
0.0
7.049e+37
0.0
1.161e+38
0.1
18
A'
242
242
242
245
5.465e+39
3.8
3.266e+39
2.3
8.732e+39
6.1
19
B'
264
264
264
264
7.723e+36
0.0
8.980e+36
0.0
1.670e+37
0.0
20
A'
266
266
266
266
8.418e+38
0.6
1.533e+38
0.1
9.951e+38
0.7
21
A'
278
278
278
279
9.367e+39
6.6
5.504e+38
0.4
9.917e+39
7.0
22
B'
280
280
283
280
1.402e+38
0.1
1.490e+38
0.1
2.892e+38
0.2
23
A'
283
284
284
283
1.125e+39
0.8
4.568e+38
0.3
1.582e+39
1.1
24
B'
284
287
286
284
1.719e+38
0.1
2.884e+38
0.2
4.603e+38
0.3
25
B'
318
318
318
318
4.392e+37
0.0
7.299e+37
0.1
1.169e+38
0.1
26
B'
324
324
331
324
1.728e+38
0.1
2.680e+38
0.2
4.407e+38
0.3
27
A'
331
332
331
334
1.363e+40
9.6
6.255e+38
0.4
1.425e+40
10.0
28
A'
334
335
334
335
5.004e+38
0.4
3.627e+38
0.3
8.631e+38
0.6
29
A'
345
348
345
346
9.240e+38
0.7
3.167e+38
0.2
1.241e+39
0.9
30
B'
348
353
350
348
5.918e+37
0.0
7.227e+37
0.1
1.314e+38
0.1
31
B'
361
361
364
361
3.547e+38
0.2
3.791e+38
0.3
7.338e+38
0.5
32
A'
364
364
364
364
2.185e+38
0.2
1.051e+38
0.1
3.237e+38
0.2
33
A'
377
378
377
377
9.084e+38
0.6
7.425e+38
0.5
1.651e+39
1.2
34
B'
378
378
379
378
3.228e+38
0.2
4.789e+38
0.3
8.017e+38
0.6
35
A'
396
396
396
398
2.932e+39
2.1
3.713e+38
0.3
3.303e+39
2.3
36
B'
402
402
402
402
1.623e+38
0.1
2.467e+38
0.2
4.090e+38
0.3
37
A'
406
408
406
406
1.030e+38
0.1
3.001e+37
0.0
1.331e+38
0.1
38
B'
408
409
410
408
1.807e+38
0.1
1.924e+38
0.1
3.731e+38
0.3
39
A'
410
415
412
410
1.100e+39
0.8
1.072e+39
0.8
2.172e+39
1.5
40
B'
419
419
424
419
1.351e+38
0.1
2.150e+38
0.2
3.501e+38
0.2
41
A'
424
428
426
427
3.357e+39
2.4
6.110e+38
0.4
3.968e+39
2.8
42
B'
428
428
431
428
3.649e+37
0.0
6.143e+37
0.0
9.792e+37
0.1
43
B'
446
446
448
446
1.431e+38
0.1
2.062e+38
0.1
3.492e+38
0.2
44
A'
453
454
453
455
2.370e+40
16.7
2.198e+38
0.2
2.392e+40
16.8
45
A'
465
469
465
465
1.936e+39
1.4
2.922e+38
0.2
2.228e+39
1.6
46
B'
469
487
478
469
1.663e+38
0.1
2.752e+38
0.2
4.416e+38
0.3
47
A'
489
489
489
506
9.450e+39
6.6
4.783e+38
0.3
9.928e+39
7.0
48
B'
512
512
513
512
2.948e+38
0.2
3.369e+38
0.2
6.317e+38
0.4
49
A'
515
517
515
520
9.033e+38
0.6
6.764e+38
0.5
1.580e+39
1.1
50
B'
520
520
523
526
6.300e+36
0.0
7.346e+36
0.0
1.365e+37
0.0
51
B'
528
528
528
528
8.897e+37
0.1
1.500e+38
0.1
2.390e+38
0.2
52
A'
528
539
542
530
4.681e+38
0.3
4.253e+38
0.3
8.935e+38
0.6
53
A'
542
547
549
550
9.677e+38
0.7
7.128e+38
0.5
1.681e+39
1.2
54
A'
550
556
550
556
1.668e+38
0.1
1.065e+38
0.1
2.733e+38
0.2
55
B'
556
560
557
560
2.810e+37
0.0
4.492e+37
0.0
7.302e+37
0.1
56
B'
560
570
571
563
1.746e+38
0.1
1.903e+38
0.1
3.650e+38
0.3
57
B'
575
575
576
575
1.502e+38
0.1
2.371e+38
0.2
3.872e+38
0.3
58
A'
586
587
586
587
2.825e+38
0.2
9.452e+37
0.1
3.770e+38
0.3
59
A'
589
589
589
590
4.639e+38
0.3
3.552e+38
0.2
8.191e+38
0.6
60
A'
590
590
590
590
2.019e+38
0.1
1.527e+38
0.1
3.547e+38
0.2
61
B'
590
595
595
591
4.415e+38
0.3
4.848e+38
0.3
9.263e+38
0.7
62
B'
595
614
629
595
4.426e+37
0.0
4.888e+37
0.0
9.314e+37
0.1
63
A'
629
629
632
671
2.255e+39
1.6
6.148e+37
0.0
2.317e+39
1.6
64
B'
671
671
674
671
2.317e+38
0.2
3.542e+38
0.2
5.859e+38
0.4
65
A'
674
679
675
675
8.071e+38
0.6
5.655e+38
0.4
1.373e+39
1.0
66
A'
679
682
679
680
2.952e+39
2.1
2.102e+38
0.1
3.162e+39
2.2
67
B'
682
685
682
682
4.414e+38
0.3
4.863e+38
0.3
9.278e+38
0.7
68
B'
685
706
691
685
2.222e+38
0.2
3.426e+38
0.2
5.648e+38
0.4
69
B'
728
728
729
728
70
A'
732
732
732
732
1.321e+40
9.3
6.960e+37
0.0
1.328e+40
9.3
71
A'
753
753
753
768
1.370e+40
9.6
2.910e+38
0.2
1.399e+40
9.8
72
B'
768
768
769
769
5.687e+37
0.0
6.522e+37
0.0
1.221e+38
0.1
73
A'
794
795
794
794
8.733e+38
0.6
7.550e+38
0.5
1.628e+39
1.1
74
B'
795
795
798
795
8.966e+37
0.1
9.629e+37
0.1
1.860e+38
0.1
75
A'
806
808
806
810
6.677e+39
4.7
5.739e+38
0.4
7.251e+39
5.1
76
B'
810
810
811
811
2.116e+38
0.1
3.093e+38
0.2
5.209e+38
0.4
77
B'
880
880
882
880
3.867e+37
0.0
5.317e+37
0.0
9.184e+37
0.1
78
A'
882
888
886
882
3.907e+38
0.3
3.052e+38
0.2
6.958e+38
0.5
79
B'
891
891
891
891
1.496e+39
1.1
1.969e+39
1.4
3.465e+39
2.4
80
A'
891
904
892
892
4.910e+39
3.5
3.686e+39
2.6
8.595e+39
6.0
81
A'
947
947
947
947
3.763e+38
0.3
3.075e+38
0.2
6.838e+38
0.5
82
B'
947
949
948
947
1.544e+38
0.1
1.751e+38
0.1
3.295e+38
0.2
83
B'
967
967
967
967
2.600e+38
0.2
2.763e+38
0.2
5.364e+38
0.4
84
A'
967
981
967
967
1.668e+38
0.1
1.852e+38
0.1
3.520e+38
0.2
85
A'
992
992
992
992
1.422e+38
0.1
7.786e+37
0.1
2.201e+38
0.2
86
B'
992
999
1015
992
1.108e+38
0.1
1.389e+38
0.1
2.497e+38
0.2
87
A'
1017
1019
1017
1019
5.402e+38
0.4
3.551e+38
0.2
8.953e+38
0.6
88
B'
1021
1021
1031
1021
4.682e+37
0.0
5.692e+37
0.0
1.037e+38
0.1
89
A'
1031
1043
1043
1044
1.594e+39
1.1
2.864e+38
0.2
1.881e+39
1.3
90
B'
1044
1044
1052
1044
1.356e+38
0.1
1.442e+38
0.1
2.798e+38
0.2
91
A'
1052
1082
1086
1111
2.584e+39
1.8
7.848e+38
0.6
3.369e+39
2.4
92
B'
1111
1111
1111
1111
1.529e+37
0.0
1.870e+37
0.0
3.399e+37
0.0
93
A'
1119
1119
1119
1119
5.675e+37
0.0
6.417e+37
0.0
1.209e+38
0.1
94
B'
1119
1172
1145
1119
5.865e+36
0.0
6.329e+36
0.0
1.219e+37
0.0
95
A'
3430
3431
3430
3432
1.319e+40
9.3
7.274e+39
5.1
2.046e+40
14.4
96
B'
3432
3432
3432
3432
8.049e+37
0.1
1.354e+38
0.1
2.159e+38
0.2
97
A'
3467
3467
3467
3512
1.167e+41
82.1
2.548e+40
17.9
1.421e+41
100.0
98
B'
3513
3513
3513
3513
4.750e+38
0.3
6.598e+38
0.5
1.135e+39
0.8
99
A'
3603
3603
3603
3603
7.222e+40
50.8
4.602e+39
3.2
7.682e+40
54.0
100
B'
3603
3603
3603
3603
6.575e+39
4.6
7.277e+39
5.1
1.385e+40
9.7
101
A'
3607
3607
3607
3607
7.138e+39
5.0
4.252e+38
0.3
7.563e+39
5.3
102
B'
3607
3609
3614
3607
4.502e+38
0.3
4.800e+38
0.3
9.302e+38
0.7
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.