-    GLAUBERITE     -    Na2Ca(SO4)2

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:  15  C2/c 
Lattice parameters (Å):  10.1580  8.3330  8.5510 
Angles (°):  90  112.333  90 

Symmetry (theoretical): 

Space group:  15  C2/c 
Lattice parameters (Å):  6.3992  6.3992  8.2770 
Angles (°):  74.20  105.79  100.92 

Cell contents: 

Number of atoms:  26 
Number of atom types:  4 
Chemical composition:  0 

Atomic positions (theoretical):

Na:  0.4104  0.6910  0.0661 
Ca:  0.0576  0.0576  0.2500 
S:  0.5993  0.9696  0.3106 
O:  0.4352  0.1165  0.2815 
O:  0.6680  0.9954  0.1487 
O:  0.5109  0.7390  0.3667 
O:  0.7958  0.0366  0.4370 
Na:  0.6910  0.4104  0.4339 
S:  0.9696  0.5993  0.1894 
O:  0.1165  0.4352  0.2185 
O:  0.9954  0.6680  0.3513 
O:  0.7390  0.5109  0.1333 
O:  0.0366  0.7958  0.0630 
Na:  0.5896  0.3090  0.9339 
Ca:  0.9424  0.9424  0.7500 
S:  0.4007  0.0304  0.6894 
O:  0.5648  0.8835  0.7185 
O:  0.3320  0.0046  0.8513 
O:  0.4891  0.2610  0.6333 
O:  0.2042  0.9634  0.5630 
Na:  0.3090  0.5896  0.5661 
S:  0.0304  0.4007  0.8106 
O:  0.8835  0.5648  0.7815 
O:  0.0046  0.3320  0.6487 
O:  0.2610  0.4891  0.8667 
O:  0.9634  0.2042  0.9370 
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
Bg
77
77
77
77
5
Bu
82
84
82
83
6
Bu
97
97
97
97
7
Ag
97
98
97
100
4.513e+38
0.3
3.057e+38
0.2
7.570e+38
0.4
8
Ag
103
103
103
103
1.769e+39
1.0
7.816e+38
0.5
2.550e+39
1.5
9
Au
107
107
110
107
10
Bg
111
111
111
111
3.335e+38
0.2
5.394e+38
0.3
8.729e+38
0.5
11
Au
111
111
114
111
12
Ag
115
115
115
115
2.582e+38
0.2
1.198e+38
0.1
3.780e+38
0.2
13
Bg
125
125
125
125
1.816e+38
0.1
1.963e+38
0.1
3.779e+38
0.2
14
Au
127
127
127
127
15
Bg
127
127
127
127
4.965e+38
0.3
5.283e+38
0.3
1.025e+39
0.6
16
Ag
129
129
129
129
1.021e+38
0.1
6.493e+37
0.0
1.670e+38
0.1
17
Bu
131
135
131
132
18
Bg
135
136
135
135
3.195e+37
0.0
5.367e+37
0.0
8.563e+37
0.1
19
Au
136
137
137
136
20
Bu
137
138
138
138
21
Ag
138
147
147
147
2.848e+38
0.2
2.608e+38
0.2
5.457e+38
0.3
22
Bg
147
155
148
155
1.704e+38
0.1
2.810e+38
0.2
4.515e+38
0.3
23
Au
155
157
161
161
24
Ag
161
161
161
162
1.384e+38
0.1
1.062e+38
0.1
2.446e+38
0.1
25
Bu
177
182
177
178
26
Bu
187
188
187
187
27
Au
188
191
189
188
28
Bg
197
197
197
197
3.666e+36
0.0
5.041e+36
0.0
8.707e+36
0.0
29
Ag
201
201
201
201
1.040e+39
0.6
3.019e+37
0.0
1.070e+39
0.6
30
Bg
204
204
204
204
2.518e+38
0.1
4.190e+38
0.2
6.708e+38
0.4
31
Au
220
220
224
220
32
Ag
226
226
226
226
1.374e+39
0.8
9.399e+38
0.5
2.314e+39
1.4
33
Bg
230
230
230
230
4.689e+38
0.3
7.683e+38
0.4
1.237e+39
0.7
34
Bu
233
236
233
233
35
Ag
239
239
239
239
3.534e+38
0.2
2.628e+38
0.2
6.162e+38
0.4
36
Bu
243
247
243
247
37
Bg
247
248
247
248
2.971e+37
0.0
4.793e+37
0.0
7.763e+37
0.0
38
Au
248
251
260
282
39
Bg
311
311
311
311
2.020e+38
0.1
2.207e+38
0.1
4.227e+38
0.2
40
Bu
315
327
315
325
41
Au
327
333
333
327
42
Ag
333
357
366
333
2.863e+38
0.2
1.295e+38
0.1
4.158e+38
0.2
43
Bg
428
428
428
428
6.410e+38
0.4
1.044e+39
0.6
1.685e+39
1.0
44
Ag
433
433
433
433
6.802e+39
4.0
7.412e+39
4.3
1.421e+40
8.3
45
Bu
435
435
435
435
46
Au
437
437
438
437
47
Bg
469
469
469
469
6.270e+39
3.7
9.333e+39
5.5
1.560e+40
9.1
48
Bu
473
474
473
474
49
Ag
484
484
484
484
2.480e+39
1.4
1.219e+39
0.7
3.699e+39
2.2
50
Au
493
493
493
493
51
Bu
581
582
581
587
52
Au
587
587
588
593
53
Ag
593
593
593
596
5.311e+39
3.1
4.037e+39
2.4
9.348e+39
5.5
54
Bg
600
600
600
600
1.666e+39
1.0
2.798e+39
1.6
4.464e+39
2.6
55
Bu
612
621
612
612
56
Au
621
623
623
621
57
Bg
623
624
624
623
2.125e+38
0.1
2.624e+38
0.2
4.748e+38
0.3
58
Ag
624
627
626
624
2.799e+39
1.6
2.122e+39
1.2
4.921e+39
2.9
59
Au
632
632
635
632
60
Ag
635
635
638
635
3.007e+39
1.8
2.993e+39
1.7
6.000e+39
3.5
61
Bu
638
638
642
639
62
Bg
642
642
646
642
4.419e+39
2.6
5.334e+39
3.1
9.753e+39
5.7
63
Au
983
983
983
983
64
Bu
985
985
985
985
65
Bg
987
987
987
987
5.652e+38
0.3
6.018e+38
0.4
1.167e+39
0.7
66
Ag
989
989
989
989
1.712e+41
100.0
4.008e+37
0.0
1.712e+41
100.0
67
Bu
1078
1081
1078
1097
68
Ag
1097
1097
1097
1097
4.736e+39
2.8
3.911e+39
2.3
8.647e+39
5.1
69
Au
1097
1097
1099
1120
70
Au
1120
1120
1128
1127
71
Bg
1128
1128
1133
1128
1.528e+38
0.1
2.253e+38
0.1
3.781e+38
0.2
72
Bu
1133
1144
1147
1140
73
Bu
1147
1151
1151
1151
74
Ag
1151
1152
1152
1152
3.715e+39
2.2
2.035e+39
1.2
5.750e+39
3.4
75
Ag
1152
1156
1156
1156
1.142e+40
6.7
9.267e+39
5.4
2.069e+40
12.1
76
Bg
1156
1161
1161
1161
8.466e+39
4.9
9.017e+39
5.3
1.748e+40
10.2
77
Au
1161
1166
1166
1166
78
Bg
1166
1225
1208
1179
2.367e+39
1.4
3.988e+39
2.3
6.355e+39
3.7
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.