-    DIOPSIDE     -    CaMg(SiO3)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:  15  C2/c 
Lattice parameters (Å):  9.7483  8.9246  5.2505 
Angles (°):  90  105.882  90 

Symmetry (theoretical): 

Space group:  15  C2/c 
Lattice parameters (Å):  6.6125  6.6125  5.2461 
Angles (°):  78.28  101.71  95.02 

Cell contents: 

Number of atoms:  20 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.3031  0.3031  0.2500 
Mg:  0.9083  0.9083  0.2500 
Si:  0.3786  0.8081  0.2267 
O:  0.2011  0.9701  0.1402 
O:  0.6101  0.8873  0.3125 
O:  0.3646  0.6657  0.9953 
Si:  0.8081  0.3786  0.2733 
O:  0.9701  0.2011  0.3598 
O:  0.8873  0.6101  0.1875 
O:  0.6657  0.3646  0.5047 
Ca:  0.6969  0.6969  0.7500 
Mg:  0.0917  0.0917  0.7500 
Si:  0.6214  0.1919  0.7733 
O:  0.7989  0.0299  0.8598 
O:  0.3899  0.1127  0.6875 
O:  0.6354  0.3343  0.0047 
Si:  0.1919  0.6214  0.7267 
O:  0.0299  0.7989  0.6402 
O:  0.1127  0.3899  0.8125 
O:  0.3343  0.6354  0.4953 
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.