-    ALUNITE     -    KAl3(SO4)2(OH)6

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:  166  R-3m 
Lattice parameters (Å):  6.9749  6.9749  17.3150 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  166  R-3m 
Lattice parameters (Å):  6.7091  6.7091  6.7091 
Angles (°):  61.38  61.38  61.38 

Cell contents: 

Number of atoms:  26 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

K:  0.0000  0.0000  0.0000 
Al:  0.5000  0.0000  0.0000 
S:  0.3099  0.3099  0.3099 
O:  0.4000  0.4000  0.4000 
O:  0.1628  0.5145  0.1628 
O:  0.2650  0.8873  0.2650 
H:  0.3142  0.7111  0.3142 
Al:  0.0000  0.0000  0.5000 
O:  0.5145  0.1628  0.1628 
O:  0.8873  0.2650  0.2650 
H:  0.7111  0.3142  0.3142 
Al:  0.0000  0.5000  0.0000 
O:  0.1628  0.1628  0.5145 
O:  0.2650  0.2650  0.8873 
H:  0.3142  0.3142  0.7111 
S:  0.6901  0.6901  0.6901 
O:  0.6000  0.6000  0.6000 
O:  0.8372  0.4855  0.8372 
O:  0.7350  0.1127  0.7350 
H:  0.6858  0.2889  0.6858 
O:  0.4855  0.8372  0.8372 
O:  0.1127  0.7350  0.7350 
H:  0.2889  0.6858  0.6858 
O:  0.8372  0.8372  0.4855 
O:  0.7350  0.7350  0.1127 
H:  0.6858  0.6858  0.2889 
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
Eu
135
135
135
135
5
Eu
135
139
139
135
6
A1u
169
169
169
169
7
Eg
172
172
172
172
1.322e+39
0.9
2.021e+39
1.4
3.343e+39
2.3
8
Eg
172
172
172
172
1.322e+39
0.9
1.706e+39
1.2
3.028e+39
2.1
9
A2g
175
175
175
175
10
A2u
184
184
184
190
11
Eu
209
209
209
209
12
Eu
209
209
209
209
13
Eu
229
229
229
229
14
Eu
229
232
232
229
15
A1g
241
241
241
241
1.787e+40
12.3
6.663e+38
0.5
1.854e+40
12.8
16
Eg
250
250
250
250
1.336e+39
0.9
1.291e+39
0.9
2.628e+39
1.8
17
Eg
250
250
250
250
1.336e+39
0.9
1.853e+39
1.3
3.189e+39
2.2
18
Eg
272
272
272
272
5.419e+38
0.4
4.412e+38
0.3
9.831e+38
0.7
19
Eg
272
272
272
272
5.419e+38
0.4
8.541e+38
0.6
1.396e+39
1.0
20
A1u
293
293
293
293
21
Eu
298
298
298
298
22
Eu
298
308
308
298
23
A2u
318
318
318
318
24
Eu
328
328
328
328
25
Eu
328
345
345
328
26
A1g
350
350
350
350
7.154e+39
4.9
2.187e+36
0.0
7.156e+39
4.9
27
Eu
366
366
366
366
28
Eu
366
382
382
366
29
A2u
408
408
408
409
30
Eg
409
409
409
409
3.659e+39
2.5
5.084e+39
3.5
8.743e+39
6.0
31
Eg
409
409
409
466
3.659e+39
2.5
3.096e+39
2.1
6.756e+39
4.7
32
Eg
474
474
474
474
4.223e+39
2.9
4.101e+39
2.8
8.324e+39
5.7
33
Eg
474
474
474
474
4.223e+39
2.9
4.507e+39
3.1
8.730e+39
6.0
34
Eu
478
478
478
478
35
Eu
478
479
479
478
36
A2g
482
482
482
482
37
A2u
519
519
519
533
38
A1g
533
533
533
535
8.168e+39
5.6
5.842e+37
0.0
8.226e+39
5.7
39
A2u
567
567
567
567
40
Eg
598
598
598
598
4.795e+39
3.3
6.409e+39
4.4
1.120e+40
7.7
41
Eg
598
598
598
598
4.795e+39
3.3
7.014e+39
4.8
1.181e+40
8.1
42
Eu
605
605
605
605
43
Eu
605
614
614
605
44
Eu
631
631
631
631
45
Eu
631
634
634
631
46
A1g
634
636
636
634
9.459e+39
6.5
2.431e+39
1.7
1.189e+40
8.2
47
Eg
636
636
636
636
1.230e+39
0.8
1.963e+39
1.4
3.193e+39
2.2
48
Eg
636
640
640
636
1.230e+39
0.8
1.564e+39
1.1
2.794e+39
1.9
49
A2u
640
650
650
654
50
Eu
656
656
656
656
51
Eu
656
674
674
656
52
A1u
674
699
699
674
53
A2u
700
700
700
708
54
Eg
708
708
708
708
2.300e+38
0.2
2.314e+38
0.2
4.614e+38
0.3
55
Eg
708
708
708
788
2.300e+38
0.2
2.810e+38
0.2
5.110e+38
0.4
56
Eu
788
788
788
788
57
Eu
788
802
802
789
58
A1g
914
914
914
914
4.189e+39
2.9
3.168e+37
0.0
4.220e+39
2.9
59
A2u
1005
1005
1005
1006
60
A1g
1006
1006
1006
1006
1.317e+41
90.7
2.007e+37
0.0
1.317e+41
90.7
61
A2g
1054
1054
1054
1054
62
Eg
1100
1100
1100
1100
2.751e+39
1.9
2.525e+39
1.7
5.276e+39
3.6
63
Eg
1100
1100
1100
1100
2.751e+39
1.9
4.560e+39
3.1
7.312e+39
5.0
64
Eu
1103
1103
1103
1103
65
Eu
1103
1124
1124
1103
66
A1u
1124
1133
1133
1124
67
A1g
1133
1140
1140
1133
1.217e+40
8.4
2.392e+39
1.6
1.456e+40
10.0
68
A2u
1140
1178
1178
1178
69
Eg
1178
1178
1178
1178
1.866e+39
1.3
2.325e+39
1.6
4.191e+39
2.9
70
Eg
1178
1184
1184
1185
1.866e+39
1.3
2.959e+39
2.0
4.825e+39
3.3
71
Eu
1185
1185
1185
1185
72
Eu
1185
1190
1190
1228
73
Eg
3289
3289
3289
3289
3.376e+40
23.2
4.851e+40
33.4
8.227e+40
56.6
74
Eg
3289
3289
3289
3289
3.376e+40
23.2
2.855e+40
19.7
6.231e+40
42.9
75
Eu
3296
3296
3296
3296
76
Eu
3296
3332
3332
3296
77
A2u
3362
3362
3362
3369
78
A1g
3369
3369
3369
3397
1.451e+41
99.9
1.301e+38
0.1
1.452e+41
100.0
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.