-    DICKITE     -    Al2Si2O5(OH)4

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:  Cc 
Lattice parameters (Å):  5.1610  8.9600  14.4590 
Angles (°):  90  96.77  90 

Symmetry (theoretical): 

Space group:  Cc 
Lattice parameters (Å):  5.0488  5.0488  14.0523 
Angles (°):  87.05  92.94  60.06 

Cell contents: 

Number of atoms:  34 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Si:  0.4116  0.3821  0.0298 
Si:  0.0703  0.0663  0.0293 
Al:  0.1556  0.3393  0.2238 
Al:  0.8267  0.9964  0.2226 
O:  0.1730  0.2948  0.9811 
O:  0.7288  0.1844  0.9811 
O:  0.2943  0.7330  0.9977 
O:  0.4644  0.3053  0.1426 
O:  0.0793  0.0762  0.1424 
O:  0.8476  0.6889  0.1476 
O:  0.5102  0.0232  0.2887 
O:  0.1458  0.6500  0.2891 
O:  0.8834  0.2746  0.2880 
H:  0.6546  0.6902  0.1403 
H:  0.5457  0.9766  0.3581 
H:  0.3366  0.6479  0.3042 
H:  0.8716  0.2834  0.3571 
Si:  0.6179  0.5884  0.5298 
Si:  0.9337  0.9297  0.5293 
Al:  0.6607  0.8444  0.7238 
Al:  0.0036  0.1733  0.7226 
O:  0.7052  0.8270  0.4811 
O:  0.8156  0.2712  0.4811 
O:  0.2670  0.7057  0.4977 
O:  0.6947  0.5356  0.6426 
O:  0.9238  0.9207  0.6424 
O:  0.3111  0.1524  0.6476 
O:  0.9768  0.4898  0.7887 
O:  0.3500  0.8542  0.7891 
O:  0.7254  0.1166  0.7880 
H:  0.3098  0.3454  0.6403 
H:  0.0234  0.4543  0.8581 
H:  0.3521  0.6634  0.8042 
H:  0.7166  0.1284  0.8571 
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.