-    RANKINITE     -    Ca3Si2O7

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:  14  P2_1/a 
Lattice parameters (Å):  10.5570  8.8850  7.8580 
Angles (°):  90  119.58  90 

Symmetry (theoretical): 

Space group:  14  P2_1/a 
Lattice parameters (Å):  10.5807  8.8823  7.8503 
Angles (°):  90  119.68  90 

Cell contents: 

Number of atoms:  48 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.0124  0.0545  0.2895 
Ca:  0.1678  0.5747  0.2135 
Ca:  0.3389  0.9068  0.2831 
Si:  0.0897  0.2153  0.9816 
Si:  0.2955  0.2330  0.4295 
O:  0.3560  0.3956  0.4181 
O:  0.1803  0.2373  0.5062 
O:  0.4089  0.1008  0.5431 
O:  0.1996  0.1539  0.2076 
O:  0.0953  0.3950  0.9713 
O:  0.1468  0.1450  0.8453 
O:  0.9281  0.1582  0.9242 
Ca:  0.4876  0.5545  0.7105 
Ca:  0.3322  0.0747  0.7865 
Ca:  0.1611  0.4068  0.7169 
Si:  0.4103  0.7153  0.0184 
Si:  0.2045  0.7330  0.5705 
O:  0.1440  0.8956  0.5819 
O:  0.3197  0.7373  0.4938 
O:  0.0911  0.6008  0.4569 
O:  0.3004  0.6539  0.7924 
O:  0.4047  0.8950  0.0287 
O:  0.3532  0.6450  0.1547 
O:  0.5719  0.6582  0.0758 
Ca:  0.9876  0.9455  0.7105 
Ca:  0.8322  0.4253  0.7865 
Ca:  0.6611  0.0932  0.7169 
Si:  0.9103  0.7847  0.0184 
Si:  0.7045  0.7670  0.5705 
O:  0.6440  0.6044  0.5819 
O:  0.8197  0.7627  0.4938 
O:  0.5911  0.8992  0.4569 
O:  0.8004  0.8461  0.7924 
O:  0.9047  0.6050  0.0287 
O:  0.8532  0.8550  0.1547 
O:  0.0719  0.8418  0.0758 
Ca:  0.5124  0.4455  0.2895 
Ca:  0.6678  0.9253  0.2135 
Ca:  0.8389  0.5932  0.2831 
Si:  0.5897  0.2847  0.9816 
Si:  0.7955  0.2670  0.4295 
O:  0.8560  0.1044  0.4181 
O:  0.6803  0.2627  0.5062 
O:  0.9089  0.3992  0.5431 
O:  0.6996  0.3461  0.2076 
O:  0.5953  0.1050  0.9713 
O:  0.6468  0.3550  0.8453 
O:  0.4281  0.3418  0.9242 
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
Au
60
60
61
60
5
Ag
72
72
72
72
1.358e+39
2.4
2.775e+38
0.5
1.635e+39
2.9
6
Bg
95
95
95
95
3.090e+38
0.6
4.571e+38
0.8
7.661e+38
1.4
7
Bu
109
109
109
117
8
Ag
122
122
122
122
6.488e+38
1.2
4.948e+37
0.1
6.983e+38
1.3
9
Bg
123
123
123
123
6.885e+37
0.1
1.155e+38
0.2
1.844e+38
0.3
10
Au
129
129
130
129
11
Ag
131
131
131
131
2.061e+38
0.4
1.017e+38
0.2
3.078e+38
0.6
12
Bu
137
138
137
138
13
Ag
138
138
138
138
9.044e+38
1.6
1.571e+37
0.0
9.201e+38
1.7
14
Au
139
139
139
139
15
Bu
142
142
142
142
16
Bu
142
144
142
143
17
Ag
149
149
149
149
8.851e+38
1.6
2.800e+37
0.1
9.131e+38
1.6
18
Bu
150
150
150
152
19
Bg
155
155
155
155
1.403e+38
0.3
2.315e+38
0.4
3.717e+38
0.7
20
Bu
156
156
156
156
21
Bu
156
156
157
158
22
Au
159
159
162
159
23
Ag
168
168
168
168
6.707e+38
1.2
6.256e+37
0.1
7.332e+38
1.3
24
Bg
169
169
169
169
8.730e+37
0.2
1.473e+38
0.3
2.346e+38
0.4
25
Au
172
172
173
172
26
Bg
173
173
174
173
27
Ag
176
176
176
176
6.120e+37
0.1
5.711e+37
0.1
1.183e+38
0.2
28
Au
181
181
181
181
29
Bg
188
188
188
188
4.110e+38
0.7
4.369e+38
0.8
8.479e+38
1.5
30
Bu
189
190
189
189
31
Au
191
191
192
191
32
Bu
192
193
193
192
33
Ag
195
195
195
195
3.865e+38
0.7
2.711e+38
0.5
6.576e+38
1.2
34
Ag
203
203
203
203
9.119e+37
0.2
4.961e+37
0.1
1.408e+38
0.3
35
Au
203
203
205
203
36
Bg
212
212
212
212
1.459e+38
0.3
1.908e+38
0.3
3.368e+38
0.6
37
Bu
215
215
215
215
38
Bu
215
216
215
220
39
Bg
220
220
220
222
1.699e+38
0.3
1.904e+38
0.3
3.603e+38
0.6
40
Ag
222
222
222
226
2.607e+39
4.7
1.561e+38
0.3
2.763e+39
5.0
41
Bg
226
226
226
232
2.263e+38
0.4
3.112e+38
0.6
5.375e+38
1.0
42
Bg
232
232
232
234
2.369e+37
0.0
3.258e+37
0.1
5.627e+37
0.1
43
Ag
234
234
234
237
3.033e+38
0.5
1.448e+38
0.3
4.481e+38
0.8
44
Ag
237
237
237
239
4.347e+38
0.8
5.304e+38
1.0
9.651e+38
1.7
45
Au
239
239
241
243
46
Au
243
243
244
243
47
Bu
244
248
249
249
48
Bg
249
249
250
250
2.535e+38
0.5
3.242e+38
0.6
5.778e+38
1.0
49
Bg
254
254
254
254
2.614e+38
0.5
3.448e+38
0.6
6.063e+38
1.1
50
Ag
255
255
255
255
5.804e+38
1.0
5.613e+37
0.1
6.366e+38
1.1
51
Au
259
259
262
259
52
Ag
262
262
264
262
4.867e+38
0.9
2.261e+38
0.4
7.128e+38
1.3
53
Bu
264
265
266
265
54
Au
266
266
267
266
55
Bg
267
267
270
267
3.124e+38
0.6
4.402e+38
0.8
7.526e+38
1.4
56
Bu
270
270
273
273
57
Au
273
273
280
273
58
Bu
280
284
282
281
59
Bg
284
284
284
284
5.951e+38
1.1
7.851e+38
1.4
1.380e+39
2.5
60
Ag
289
289
289
289
4.853e+38
0.9
3.000e+38
0.5
7.853e+38
1.4
61
Bg
290
290
290
290
3.691e+37
0.1
6.188e+37
0.1
9.878e+37
0.2
62
Au
295
295
295
295
63
Ag
295
295
297
295
8.169e+38
1.5
6.900e+38
1.2
1.507e+39
2.7
64
Bu
298
300
298
299
65
Au
300
301
301
300
66
Bg
301
308
308
301
1.980e+38
0.4
3.142e+38
0.6
5.123e+38
0.9
67
Bu
308
313
313
309
68
Ag
313
320
318
313
5.464e+38
1.0
2.868e+38
0.5
8.332e+38
1.5
69
Ag
320
327
320
320
9.976e+38
1.8
2.771e+38
0.5
1.275e+39
2.3
70
Au
327
329
328
327
71
Bg
329
331
329
329
1.755e+39
3.2
2.037e+39
3.7
3.791e+39
6.8
72
Bu
332
339
332
339
73
Au
339
347
348
340
74
Bu
348
350
352
352
75
Ag
352
352
353
353
3.508e+39
6.3
3.171e+39
5.7
6.679e+39
12.0
76
Au
353
353
353
353
77
Bg
353
353
358
353
2.418e+38
0.4
3.884e+38
0.7
6.302e+38
1.1
78
Bu
358
360
361
359
79
Bg
364
364
364
364
4.248e+38
0.8
6.873e+38
1.2
1.112e+39
2.0
80
Ag
370
370
370
370
4.488e+38
0.8
5.581e+38
1.0
1.007e+39
1.8
81
Bu
372
373
372
373
82
Au
373
373
373
373
83
Bg
373
377
384
373
2.397e+38
0.4
3.749e+38
0.7
6.146e+38
1.1
84
Ag
384
384
391
384
8.393e+38
1.5
4.603e+38
0.8
1.300e+39
2.3
85
Bg
410
410
410
410
2.818e+38
0.5
4.718e+38
0.8
7.536e+38
1.4
86
Ag
419
419
419
419
1.283e+39
2.3
9.826e+38
1.8
2.265e+39
4.1
87
Bu
420
423
420
421
88
Au
423
433
425
423
89
Ag
448
448
448
448
7.721e+38
1.4
2.451e+38
0.4
1.017e+39
1.8
90
Bg
450
450
450
450
5.492e+38
1.0
6.046e+38
1.1
1.154e+39
2.1
91
Au
452
452
456
452
92
Bu
456
456
457
457
93
Bu
465
466
465
470
94
Ag
470
470
470
470
9.855e+38
1.8
1.245e+39
2.2
2.230e+39
4.0
95
Ag
470
470
472
472
7.485e+37
0.1
9.398e+37
0.2
1.688e+38
0.3
96
Bu
472
472
472
472
97
Ag
472
472
472
476
4.478e+38
0.8
4.168e+38
0.7
8.646e+38
1.6
98
Bg
476
476
476
501
3.614e+38
0.6
5.987e+38
1.1
9.601e+38
1.7
99
Bg
501
501
501
509
5.559e+38
1.0
9.031e+38
1.6
1.459e+39
2.6
100
Ag
509
509
509
512
1.605e+39
2.9
1.784e+38
0.3
1.784e+39
3.2
101
Au
512
512
513
513
102
Bu
521
523
521
521
103
Au
523
523
523
523
104
Bg
523
524
523
523
3.645e+38
0.7
5.236e+38
0.9
8.882e+38
1.6
105
Bu
528
534
528
534
106
Ag
534
534
534
534
1.064e+39
1.9
1.391e+38
0.2
1.203e+39
2.2
107
Au
534
542
540
545
108
Bg
545
545
545
545
6.201e+38
1.1
9.433e+38
1.7
1.563e+39
2.8
109
Ag
545
545
545
545
1.522e+39
2.7
1.187e+39
2.1
2.709e+39
4.9
110
Au
548
548
550
548
111
Bu
550
551
551
551
112
Bg
551
560
554
567
8.480e+38
1.5
1.335e+39
2.4
2.183e+39
3.9
113
Au
641
641
649
641
114
Bg
651
651
651
651
2.321e+37
0.0
2.863e+37
0.1
5.184e+37
0.1
115
Ag
657
657
657
657
1.480e+40
26.6
1.578e+38
0.3
1.496e+40
26.9
116
Bu
668
668
668
668
117
Bu
832
833
832
833
118
Au
833
834
834
835
119
Ag
835
835
835
839
1.728e+39
3.1
4.078e+37
0.1
1.769e+39
3.2
120
Bg
839
839
839
854
1.271e+38
0.2
1.357e+38
0.2
2.628e+38
0.5
121
Ag
877
877
877
877
5.542e+40
99.6
2.400e+38
0.4
5.566e+40
100.0
122
Bg
884
884
884
884
9.623e+37
0.2
1.371e+38
0.2
2.334e+38
0.4
123
Bu
891
894
891
894
124
Au
897
897
901
897
125
Bu
920
921
920
927
126
Ag
930
930
930
930
3.480e+36
0.0
1.675e+36
0.0
5.155e+36
0.0
127
Ag
930
930
931
930
1.381e+38
0.2
6.251e+37
0.1
2.006e+38
0.4
128
Bu
933
933
933
933
129
Bg
933
933
933
935
3.378e+38
0.6
3.596e+38
0.6
6.974e+38
1.3
130
Ag
935
935
935
939
1.846e+39
3.3
6.057e+38
1.1
2.452e+39
4.4
131
Au
939
939
942
943
132
Bu
945
949
945
949
133
Au
949
958
955
958
134
Bg
958
958
958
958
7.893e+39
14.2
7.715e+38
1.4
8.664e+39
15.6
135
Bg
958
969
958
962
1.717e+39
3.1
3.946e+38
0.7
2.112e+39
3.8
136
Ag
969
970
969
969
6.491e+39
11.7
8.012e+38
1.4
7.292e+39
13.1
137
Au
973
973
973
973
138
Bu
973
981
981
981
139
Bg
981
989
988
989
4.756e+37
0.1
7.719e+37
0.1
1.247e+38
0.2
140
Au
989
992
994
989
141
Bu
994
1000
1000
1000
142
Ag
1000
1002
1002
1002
8.568e+38
1.5
9.146e+38
1.6
1.771e+39
3.2
143
Bg
1002
1029
1041
1005
5.174e+38
0.9
8.047e+38
1.4
1.322e+39
2.4
144
Bg
1041
1041
1045
1041
1.989e+39
3.6
2.640e+39
4.7
4.630e+39
8.3
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.