-    NORDENSKIOLDINE     -    CaSn(BO3)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:  148  R-3 
Lattice parameters (Å):  4.8580  4.8580  16.0800 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  148  R-3 
Lattice parameters (Å):  6.0957  6.0957  6.0957 
Angles (°):  46.69  46.69  46.60 

Cell contents: 

Number of atoms:  10 
Number of atom types:  4 
Chemical composition:  0 

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
Sn:  0.5000  0.5000  0.5000 
B:  0.2358  0.2358  0.2358 
O:  0.9363  0.2794  0.5000 
O:  0.2794  0.5000  0.9363 
O:  0.5000  0.9363  0.2794 
B:  0.7642  0.7642  0.7642 
O:  0.0637  0.7206  0.5000 
O:  0.7206  0.5000  0.0637 
O:  0.5000  0.0637  0.7206 
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
Eu
172
172
172
172
5
Eu
172
187
187
172
6
Au
202
202
202
207
7
Eg
207
207
207
207
2.091e+39
1.7
2.604e+39
2.1
4.695e+39
3.8
8
Eg
207
207
207
243
2.091e+39
1.7
2.637e+39
2.1
4.728e+39
3.8
9
Eu
243
243
243
243
10
Eu
243
271
271
271
11
Ag
271
273
273
271
3.458e+39
2.8
1.386e+39
1.1
4.844e+39
3.9
12
Au
287
287
287
287
13
Eu
370
370
370
370
14
Eu
370
381
381
370
15
Eg
381
381
381
381
3.617e+39
2.9
4.539e+39
3.6
8.155e+39
6.5
16
Eg
381
389
389
381
3.617e+39
2.9
2.778e+39
2.2
6.395e+39
5.1
17
Au
389
431
431
431
18
Ag
431
446
446
434
1.244e+41
99.7
4.323e+38
0.3
1.249e+41
100.0
19
Eg
634
634
634
634
5.719e+38
0.5
7.756e+38
0.6
1.348e+39
1.1
20
Eg
634
634
634
634
5.719e+38
0.5
8.428e+38
0.7
1.415e+39
1.1
21
Eu
649
649
649
649
22
Eu
649
656
656
649
23
Au
715
715
715
734
24
Ag
734
734
734
772
1.384e+40
11.1
1.909e+39
1.5
1.575e+40
12.6
25
Au
950
950
950
952
26
Ag
952
952
952
952
1.723e+39
1.4
8.851e+38
0.7
2.608e+39
2.1
27
Eg
1224
1224
1224
1224
1.284e+39
1.0
1.751e+39
1.4
3.035e+39
2.4
28
Eg
1224
1224
1224
1224
1.284e+39
1.0
1.382e+39
1.1
2.665e+39
2.1
29
Eu
1229
1229
1229
1229
30
Eu
1229
1382
1382
1229
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.