-    PLAGIOCLASE     -    (Na,Ca)(Si,Al)4O8

ANDESINE - Theoretical structure, term in the plagioclase series treated as ideal solid solution using alchemical pseudopotentials. The crystal structure is fully relaxed (both unit cell parameters and atomic positions under symmetry constraints) 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:  P-1 
Lattice parameters (Å):  7.599  7.533  6.081 
Angles (°):  106.12  101.66  114.92 

Symmetry (theoretical): 

Space group:  P-1 
Lattice parameters (Å):  7.6269  7.5268  7.0355 
Angles (°):  105.7  101.9  114.7 

Cell contents: 

Number of atoms:  26 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Na:  0.2569  0.2747  0.1231 
Si:  0.8379  0.1753  0.2197 
Si:  0.1877  0.8238  0.2274 
Si:  0.5738  0.7990  0.3272 
Si:  0.8072  0.5691  0.3496 
O:  0.8686  0.1323  0.9896 
O:  0.5956  0.5840  0.2800 
O:  0.7010  0.9331  0.2046 
O:  0.9613  0.6809  0.2352 
O:  0.7259  0.3142  0.2699 
O:  0.3232  0.7031  0.2241 
O:  0.0783  0.3043  0.3909 
O:  0.3260  0.0617  0.4181 
Na:  0.7431  0.7253  0.8769 
Si:  0.1621  0.8247  0.7803 
Si:  0.8123  0.1762  0.7726 
Si:  0.4262  0.2010  0.6728 
Si:  0.1928  0.4309  0.6504 
O:  0.1314  0.8677  0.0104 
O:  0.4044  0.4160  0.7200 
O:  0.2990  0.0669  0.7954 
O:  0.0387  0.3191  0.7648 
O:  0.2741  0.6858  0.7301 
O:  0.6768  0.2969  0.7759 
O:  0.9217  0.6957  0.6091 
O:  0.6740  0.9383  0.5819 
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.