-    ARMALCOLITE     -    MgTi2O5

 

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:  63  Cmcm 
Lattice parameters (Å):  3.7504  9.7762  10.0341 
Angles (°):  90  90  90 

Symmetry (theoretical): 

Space group:  63  Cmcm 
Lattice parameters (Å):  5.1235  5.1235  9.7483 
Angles (°):  90  90  42.46 

Cell contents: 

Number of atoms:  16 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Mg:  0.8010  0.8010  0.2500 
Mg:  0.1350  0.1350  0.4365 
Mg:  0.2160  0.2160  0.2500 
Mg:  0.0482  0.0482  0.8859 
Mg:  0.3130  0.3130  0.9402 
Ti:  0.1990  0.1990  0.7500 
Ti:  0.8650  0.8650  0.9365 
O:  0.7840  0.7840  0.7500 
O:  0.9518  0.9518  0.3859 
0.6870  0.6870  0.4402 
0.1350  0.1350  0.0635 
0.0482  0.0482  0.6141 
0.3130  0.3130  0.5598 
0.8650  0.8650  0.5635 
0.9518  0.9518  0.1141 
0.6870  0.6870  0.0598 
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
126
126
126
126
5
B1u
132
132
132
132
6
B2g
153
153
153
153
5.783e+40
6.4
7.952e+40
8.8
1.374e+41
15.1
7
B1g
174
174
174
174
1.634e+40
1.8
2.246e+40
2.5
3.880e+40
4.3
8
B1g
188
188
188
188
1.748e+41
19.3
2.404e+41
26.5
4.152e+41
45.8
9
Ag
224
224
224
224
1.945e+40
2.1
1.420e+40
1.6
3.365e+40
3.7
10
B2g
224
224
224
224
5.193e+37
0.0
7.140e+37
0.0
1.233e+38
0.0
11
B2u
226
226
226
226
12
B3g
230
230
230
230
5.671e+39
0.6
7.798e+39
0.9
1.347e+40
1.5
13
B3u
267
267
267
267
14
B1g
272
272
272
272
2.069e+41
22.8
2.845e+41
31.4
4.913e+41
54.2
15
Au
278
278
278
278
16
B3u
286
303
286
286
17
B3g
303
304
303
303
2.133e+39
0.2
2.933e+39
0.3
5.065e+39
0.6
18
Ag
304
311
304
304
1.043e+41
11.5
6.958e+40
7.7
1.739e+41
19.2
19
B1u
312
312
312
338
20
B2u
338
338
343
346
21
B3g
346
346
346
349
6.553e+37
0.0
9.010e+37
0.0
1.556e+38
0.0
22
Ag
349
349
349
351
8.692e+40
9.6
5.981e+40
6.6
1.467e+41
16.2
23
B1u
363
363
363
382
24
B2u
382
382
389
389
25
Ag
389
389
389
392
2.613e+40
2.9
1.656e+40
1.8
4.269e+40
4.7
26
B2u
392
392
403
403
27
B1u
403
403
439
416
28
B3g
439
439
442
439
2.456e+40
2.7
3.377e+40
3.7
5.833e+40
6.4
29
B2u
466
466
473
466
30
Ag
473
473
484
473
9.531e+40
10.5
5.437e+40
6.0
1.497e+41
16.5
31
B3u
484
493
493
484
32
B3g
493
500
500
493
2.923e+40
3.2
4.019e+40
4.4
6.941e+40
7.7
33
B1g
500
524
524
500
5.414e+40
6.0
7.445e+40
8.2
1.286e+41
14.2
34
B1u
524
524
524
524
35
Ag
524
537
537
537
8.279e+39
0.9
5.904e+39
0.7
1.418e+40
1.6
36
B3g
537
548
567
567
1.694e+39
0.2
2.329e+39
0.3
4.022e+39
0.4
37
Ag
567
567
585
585
1.153e+40
1.3
8.086e+39
0.9
1.962e+40
2.2
38
Au
585
585
585
613
39
B3u
613
628
613
627
40
B1u
628
694
628
694
41
B3g
694
708
694
708
1.305e+39
0.1
1.795e+39
0.2
3.100e+39
0.3
42
B2g
708
712
708
712
3.192e+39
0.4
4.389e+39
0.5
7.582e+39
0.8
43
B2u
712
717
717
717
44
B1g
717
771
732
721
3.820e+41
42.1
5.252e+41
57.9
9.072e+41
100.0
45
B1u
771
802
771
802
46
B2u
802
819
819
819
47
B3g
819
833
833
821
7.807e+38
0.1
1.074e+39
0.1
1.854e+39
0.2
48
Ag
833
889
933
833
5.508e+41
60.7
2.325e+40
2.6
5.740e+41
63.3
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.