-    CALCITE     -    CaCO3

The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) at 2GPa starting from an experimental structure similar to the one reported in 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):  5.0492  5.0492  17.3430 
Angles (°):  90  90  120 

Symmetry (theoretical): 

Space group:  167  R-3c 
Lattice parameters (Å):  6.1655  6.1655  6.1655 
Angles (°):  47.73  47.73  47.73 

Cell contents: 

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

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O:  0.5056  0.9944  0.2500 
O:  0.9944  0.2500  0.5056 
Ca:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O:  0.7500  0.4944  0.0056 
O:  0.2500  0.5056  0.9944 
O:  0.4944  0.0056  0.7500 
O:  0.0056  0.7500  0.4944 
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: 


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.