-    MERWINITE     -    Ca3Mg(SiO4)2

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):  13.2540  5.2930  9.3280 
Angles (°):  90.0  91.9  90.0 

Symmetry (theoretical): 

Space group:  14  P2_1/a 
Lattice parameters (Å):  13.3168  5.2829  9.3039 
Angles (°):  90.0  92.3  90.0 

Cell contents: 

Number of atoms:  56 
Number of atom types:  4 
Chemical composition:  0 

Atomic positions (theoretical):

Ca:  0.2590  0.1779  0.2163 
Ca:  0.0795  0.2243  0.9266 
Ca:  0.0965  0.7368  0.4253 
Mg:  0.0054  0.2577  0.2537 
Si:  0.1312  0.2311  0.6027 
Si:  0.1404  0.7270  0.0928 
O:  0.0722  0.2156  0.4471 
O:  0.0623  0.4210  0.6957 
O:  0.1220  0.9540  0.6784 
O:  0.2394  0.3611  0.5987 
O:  0.0757  0.7064  0.9403 
O:  0.2530  0.8090  0.0635 
O:  0.1254  0.4724  0.1844 
O:  0.0839  0.9597  0.1734 
Ca:  0.2410  0.6779  0.7837 
Ca:  0.4205  0.7243  0.0734 
Ca:  0.4035  0.2368  0.5747 
Mg:  0.4946  0.7577  0.7463 
Si:  0.3688  0.7311  0.3973 
Si:  0.3596  0.2270  0.9072 
O:  0.4278  0.7156  0.5529 
O:  0.4377  0.9210  0.3043 
O:  0.3780  0.4540  0.3216 
O:  0.2606  0.8611  0.4013 
O:  0.4243  0.2064  0.0597 
O:  0.2470  0.3090  0.9365 
O:  0.3746  0.9724  0.8156 
O:  0.4161  0.4597  0.8266 
Ca:  0.7410  0.8221  0.7837 
Ca:  0.9205  0.7757  0.0734 
Ca:  0.9035  0.2632  0.5747 
Mg:  0.9946  0.7423  0.7463 
Si:  0.8688  0.7689  0.3973 
Si:  0.8596  0.2730  0.9072 
O:  0.9278  0.7844  0.5529 
O:  0.9377  0.5790  0.3043 
O:  0.8780  0.0460  0.3216 
O:  0.7606  0.6389  0.4013 
O:  0.9243  0.2936  0.0597 
O:  0.7470  0.1910  0.9365 
O:  0.8746  0.5276  0.8156 
O:  0.9161  0.0403  0.8266 
Ca:  0.7590  0.3221  0.2163 
Ca:  0.5795  0.2757  0.9266 
Ca:  0.5965  0.7632  0.4253 
Mg:  0.5054  0.2423  0.2537 
Si:  0.6312  0.2689  0.6027 
Si:  0.6404  0.7730  0.0928 
O:  0.5722  0.2844  0.4471 
O:  0.5623  0.0790  0.6957 
O:  0.6220  0.5460  0.6784 
O:  0.7394  0.1389  0.5987 
O:  0.5757  0.7936  0.9403 
O:  0.7530  0.6910  0.0635 
O:  0.6254  0.0276  0.1844 
O:  0.5839  0.5403  0.1734 
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
Ag
43
43
43
43
7.603e+38
1.8
4.947e+38
1.2
1.255e+39
3.0
5
Bg
69
69
69
69
4.436e+38
1.1
7.484e+38
1.8
1.192e+39
2.9
6
Au
70
70
71
70
7
Ag
81
81
81
81
4.062e+39
9.8
1.390e+39
3.4
5.451e+39
13.2
8
Bu
82
84
82
83
9
Bg
84
86
84
84
2.129e+38
0.5
2.730e+38
0.7
4.858e+38
1.2
10
Ag
92
92
92
92
7.904e+38
1.9
4.022e+38
1.0
1.193e+39
2.9
11
Au
95
95
97
95
12
Bu
105
106
105
107
13
Bg
107
107
107
110
2.954e+38
0.7
4.061e+38
1.0
7.015e+38
1.7
14
Ag
110
110
110
112
1.070e+39
2.6
2.042e+38
0.5
1.274e+39
3.1
15
Au
112
112
112
112
16
Bg
112
112
115
115
2.569e+38
0.6
3.122e+38
0.8
5.691e+38
1.4
17
Ag
115
115
115
115
5.107e+38
1.2
2.744e+38
0.7
7.851e+38
1.9
18
Au
116
116
116
116
19
Au
116
117
116
117
20
Ag
117
117
117
117
7.230e+38
1.8
3.677e+38
0.9
1.091e+39
2.6
21
Bu
121
124
121
125
22
Bg
128
128
128
128
2.182e+39
5.3
2.780e+39
6.7
4.962e+39
12.0
23
Bu
134
136
134
136
24
Ag
136
136
136
139
5.369e+38
1.3
1.829e+38
0.4
7.197e+38
1.7
25
Au
140
140
141
140
26
Bg
141
141
142
141
5.022e+38
1.2
6.277e+38
1.5
1.130e+39
2.7
27
Au
142
142
146
142
28
Bu
146
149
149
146
29
Ag
149
149
149
149
1.690e+39
4.1
1.171e+39
2.8
2.860e+39
6.9
30
Ag
152
152
152
152
3.619e+38
0.9
1.853e+38
0.4
5.472e+38
1.3
31
Bg
153
153
153
153
7.892e+37
0.2
1.169e+38
0.3
1.959e+38
0.5
32
Bu
155
156
155
156
33
Au
156
156
160
159
34
Bg
160
160
160
160
9.974e+37
0.2
1.078e+38
0.3
2.075e+38
0.5
35
Ag
161
161
161
161
3.479e+38
0.8
1.767e+38
0.4
5.247e+38
1.3
36
Au
163
163
174
163
37
Ag
174
174
174
174
3.945e+38
1.0
1.417e+38
0.3
5.361e+38
1.3
38
Ag
174
174
176
174
1.593e+38
0.4
8.709e+37
0.2
2.464e+38
0.6
39
Bu
176
176
181
182
40
Au
182
182
184
184
41
Ag
184
184
185
185
5.389e+38
1.3
4.584e+36
0.0
5.435e+38
1.3
42
Bg
185
185
186
189
1.685e+38
0.4
2.838e+38
0.7
4.523e+38
1.1
43
Au
189
189
193
193
44
Bg
193
193
194
193
1.244e+38
0.3
1.710e+38
0.4
2.954e+38
0.7
45
Bu
194
194
194
198
46
Bu
199
200
199
200
47
Au
200
200
203
211
48
Au
211
211
211
211
49
Bg
211
211
213
211
1.200e+37
0.0
1.879e+37
0.0
3.080e+37
0.1
50
Bu
213
214
214
214
51
Ag
214
214
215
215
1.063e+39
2.6
3.849e+38
0.9
1.448e+39
3.5
52
Bg
215
215
219
220
1.871e+38
0.5
2.279e+38
0.6
4.150e+38
1.0
53
Au
220
220
220
220
54
Bg
220
220
221
221
3.402e+37
0.1
3.641e+37
0.1
7.043e+37
0.2
55
Ag
221
221
228
225
1.307e+39
3.2
2.456e+38
0.6
1.553e+39
3.8
56
Bu
229
229
229
235
57
Ag
235
235
235
235
7.278e+36
0.0
7.708e+36
0.0
1.499e+37
0.0
58
Ag
235
235
237
235
1.328e+37
0.0
1.406e+37
0.0
2.735e+37
0.1
59
Bu
237
237
237
247
60
Bg
253
253
253
253
9.681e+37
0.2
1.203e+38
0.3
2.171e+38
0.5
61
Ag
253
253
253
253
9.059e+38
2.2
1.287e+38
0.3
1.035e+39
2.5
62
Bu
256
256
256
256
63
Bg
256
260
256
256
3.938e+37
0.1
5.415e+37
0.1
9.353e+37
0.2
64
Au
262
262
262
262
65
Bu
267
267
267
267
66
Bg
267
268
267
268
1.192e+38
0.3
1.766e+38
0.4
2.958e+38
0.7
67
Au
268
270
270
270
68
Ag
270
274
273
271
1.129e+39
2.7
9.341e+37
0.2
1.222e+39
3.0
69
Ag
279
279
279
279
1.313e+39
3.2
6.880e+37
0.2
1.382e+39
3.3
70
Au
280
280
280
280
71
Au
281
281
281
281
72
Bu
281
283
283
282
73
Bg
283
285
285
283
6.841e+37
0.2
1.147e+38
0.3
1.831e+38
0.4
74
Ag
288
288
288
288
6.354e+38
1.5
4.016e+38
1.0
1.037e+39
2.5
75
Bu
290
291
290
291
76
Au
291
295
295
292
77
Bu
296
301
296
296
78
Bg
301
301
301
301
1.243e+37
0.0
1.456e+37
0.0
2.699e+37
0.1
79
Ag
305
305
305
305
9.889e+37
0.2
1.036e+38
0.3
2.024e+38
0.5
80
Bg
309
309
309
309
7.699e+37
0.2
1.259e+38
0.3
2.029e+38
0.5
81
Bu
311
311
311
312
82
Bg
312
312
312
312
1.443e+37
0.0
2.396e+37
0.1
3.839e+37
0.1
83
Bg
312
312
312
313
2.237e+37
0.1
3.715e+37
0.1
5.952e+37
0.1
84
Ag
321
321
321
321
1.310e+38
0.3
7.765e+36
0.0
1.388e+38
0.3
85
Bg
327
327
327
327
6.761e+37
0.2
1.126e+38
0.3
1.802e+38
0.4
86
Bu
336
337
336
337
87
Ag
337
337
337
337
8.619e+38
2.1
8.830e+37
0.2
9.502e+38
2.3
88
Ag
337
339
339
339
2.846e+38
0.7
2.915e+37
0.1
3.137e+38
0.8
89
Bg
339
348
348
341
1.242e+37
0.0
2.096e+37
0.1
3.338e+37
0.1
90
Ag
348
352
358
348
2.973e+38
0.7
3.153e+38
0.8
6.126e+38
1.5
91
Au
364
364
365
364
92
Bu
365
368
368
368
93
Au
368
370
372
372
94
Bg
372
372
372
373
1.394e+37
0.0
2.258e+37
0.1
3.653e+37
0.1
95
Ag
373
373
373
377
4.310e+38
1.0
8.116e+37
0.2
5.122e+38
1.2
96
Bu
381
383
381
383
97
Au
383
383
383
383
98
Ag
383
383
392
392
1.756e+39
4.3
1.143e+39
2.8
2.899e+39
7.0
99
Bu
394
395
394
397
100
Bg
397
397
397
397
2.491e+38
0.6
4.102e+38
1.0
6.593e+38
1.6
101
Au
397
397
399
399
102
Ag
399
399
399
401
3.817e+38
0.9
2.882e+38
0.7
6.699e+38
1.6
103
Bu
401
406
401
406
104
Au
406
407
408
407
105
Bu
408
415
415
415
106
Ag
415
416
416
416
1.187e+39
2.9
7.699e+38
1.9
1.957e+39
4.7
107
Bg
416
418
418
418
1.340e+39
3.2
1.476e+39
3.6
2.817e+39
6.8
108
Ag
418
420
421
419
1.345e+39
3.3
9.105e+38
2.2
2.255e+39
5.5
109
Bu
421
425
422
425
110
Bg
425
425
425
425
1.677e+38
0.4
2.422e+38
0.6
4.100e+38
1.0
111
Au
425
443
443
439
112
Bg
443
448
448
443
1.512e+38
0.4
1.607e+38
0.4
3.118e+38
0.8
113
Au
481
481
481
481
114
Bu
497
498
497
498
115
Bg
498
500
498
498
2.961e+37
0.1
4.385e+37
0.1
7.346e+37
0.2
116
Au
500
502
502
500
117
Ag
502
502
502
502
3.474e+38
0.8
8.483e+37
0.2
4.322e+38
1.0
118
Bu
502
506
505
510
119
Au
511
511
514
511
120
Ag
514
514
515
514
1.041e+39
2.5
7.417e+38
1.8
1.783e+39
4.3
121
Bg
515
515
516
515
3.398e+37
0.1
4.430e+37
0.1
7.828e+37
0.2
122
Bu
517
520
517
520
123
Bu
520
522
520
522
124
Ag
522
527
522
527
1.558e+39
3.8
6.021e+37
0.1
1.618e+39
3.9
125
Bg
527
527
527
527
6.851e+38
1.7
1.034e+39
2.5
1.719e+39
4.2
126
Au
527
533
533
531
127
Ag
534
534
534
534
2.687e+38
0.7
5.332e+37
0.1
3.220e+38
0.8
128
Bg
535
535
535
535
1.516e+38
0.4
2.145e+38
0.5
3.661e+38
0.9
129
Au
536
536
536
536
130
Au
536
543
541
536
131
Bu
543
547
543
546
132
Bg
547
556
547
547
4.072e+37
0.1
5.908e+37
0.1
9.980e+37
0.2
133
Bg
556
556
556
556
2.049e+37
0.0
2.817e+37
0.1
4.866e+37
0.1
134
Ag
558
558
558
558
1.470e+38
0.4
9.576e+37
0.2
2.427e+38
0.6
135
Ag
564
564
564
564
1.044e+39
2.5
6.554e+38
1.6
1.699e+39
4.1
136
Au
573
573
576
573
137
Ag
840
840
840
840
9.662e+38
2.3
1.514e+38
0.4
1.118e+39
2.7
138
Ag
840
840
840
840
5.481e+38
1.3
2.350e+38
0.6
7.831e+38
1.9
139
Bu
841
843
841
843
140
Au
843
843
845
843
141
Ag
845
845
846
845
1.610e+40
39.0
1.551e+38
0.4
1.625e+40
39.4
142
Bu
848
849
848
849
143
Bg
849
849
849
849
1.447e+38
0.4
2.248e+38
0.5
3.695e+38
0.9
144
Au
852
852
852
852
145
Ag
858
858
858
858
4.125e+40
99.9
3.951e+37
0.1
4.129e+40
100.0
146
Bg
860
860
860
860
4.463e+37
0.1
6.509e+37
0.2
1.097e+38
0.3
147
Au
864
864
864
864
148
Bu
864
866
876
877
149
Bu
884
886
884
886
150
Bg
886
886
886
886
151
Bg
886
886
888
888
2.033e+37
0.0
2.344e+37
0.1
4.378e+37
0.1
152
Ag
893
893
893
893
1.383e+40
33.5
3.966e+38
1.0
1.422e+40
34.4
153
Bg
896
896
896
896
3.824e+38
0.9
4.113e+38
1.0
7.937e+38
1.9
154
Ag
898
898
898
898
5.392e+39
13.1
3.946e+38
1.0
5.787e+39
14.0
155
Bu
902
912
902
916
156
Ag
916
916
916
916
4.628e+37
0.1
1.633e+36
0.0
4.791e+37
0.1
157
Ag
916
916
929
929
1.802e+39
4.4
6.357e+37
0.2
1.866e+39
4.5
158
Bg
929
929
945
945
2.476e+37
0.1
3.836e+37
0.1
6.312e+37
0.2
159
Au
945
945
960
947
160
Bu
960
966
967
960
161
Bu
969
975
969
975
162
Ag
975
981
975
981
7.897e+38
1.9
5.241e+38
1.3
1.314e+39
3.2
163
Bg
981
982
981
983
1.781e+36
0.0
2.450e+36
0.0
4.231e+36
0.0
164
Au
983
983
993
991
165
Ag
994
994
994
994
2.891e+39
7.0
2.224e+39
5.4
5.115e+39
12.4
166
Bu
999
1007
999
1002
167
Au
1007
1055
1019
1007
168
Bg
1055
1056
1055
1055
1.252e+39
3.0
1.685e+39
4.1
2.937e+39
7.1
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.