-    CALCITE     -    CaCO3

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:  167   R-3c  
Lattice parameters (Å):  2.6719  2.6719  9.1775 
Angles (°):  90  90  120  

Symmetry (theoretical): 

Space group:  167   R-3c  
Lattice parameters (Å):  6.4763  6.4763  6.4763 
Angles (°):  45.88  45.88  45.88  

Cell contents: 

Number of atoms:  10  
Number of atom types:  3  
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O :  0.5039  0.9961  0.2500 
O :  0.9961  0.2500  0.5039 
Ca:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O :  0.7500  0.4961  0.0039 
O :  0.2500  0.5039  0.9961 
O :  0.4961  0.0039  0.7500 
O :  0.0039  0.7500  0.4961 
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
0
0
0
0
2
0
0
0
0
3
0
0
0
0
4
111
111
111
121
5
121
121
121
121
6
121
137
137
148
7
149
149
149
149
4.313e+39
7.6
6.969e+39
12.2
1.128e+40
19.8
8
149
149
149
149
4.313e+39
7.6
5.434e+39
9.5
9.748e+39
17.1
9
159
159
159
159
10
222
222
222
222
11
222
237
237
222
12
273
273
273
273
1.462e+40
25.6
1.899e+40
33.3
3.361e+40
58.9
13
273
273
273
273
1.462e+40
25.6
1.775e+40
31.1
3.238e+40
56.7
14
283
283
283
283
15
297
297
297
297
16
297
302
302
297
17
302
312
312
302
18
312
376
376
397
19
696
696
696
696
1.510e+39
2.6
1.188e+39
2.1
2.698e+39
4.7
20
696
696
696
696
1.510e+39
2.6
1.852e+39
3.2
3.362e+39
5.9
21
698
698
698
698
22
698
700
700
698
23
851
851
851
856
24
856
856
856
865
25
1078
1078
1078
1078
5.538e+40
97.0
1.726e+39
3.0
5.710e+40
100.0
26
1078
1078
1078
1078
5.475e+39
9.6
1.706e+38
0.3
5.645e+39
9.9
27
1396
1396
1396
1396
28
1396
1421
1421
1396
29
1421
1421
1421
1421
2.746e+39
4.8
2.640e+39
4.6
5.387e+39
9.4
30
1421
1535
1535
1421
2.746e+39
4.8
2.840e+39
5.0
5.587e+39
9.8
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.