-    WENDWILSONITE     -    Ca2Mg(AsO4)22H2O

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:  14  P2_1/c 
Lattice parameters (Å):  5.8060  12.9230  5.6280 
Angles (°):  90  107.49  90 

Symmetry (theoretical): 

Space group:  14  P2_1/c 
Lattice parameters (Å):  5.8123  12.9265  5.6318 
Angles (°):  90  107.85  90 

Cell contents: 

Number of atoms:  38 
Number of atom types:  5 
Chemical composition:  0 

Atomic positions (theoretical):

Ca:  0.5680  0.1202  0.2361 
Mg:  0.0000  0.0000  0.0000 
As:  0.2199  0.1209  0.5703 
O:  0.9498  0.1795  0.4978 
O:  0.2769  0.0530  0.8435 
O:  0.2361  0.0366  0.3422 
O:  0.4559  0.2024  0.5864 
O:  0.8174  0.1363  0.9648 
H:  0.9034  0.2069  0.0002 
H:  0.6927  0.1503  0.7988 
Ca:  0.4320  0.6202  0.2639 
Mg:  0.0000  0.5000  0.5000 
As:  0.7801  0.6209  0.9297 
O:  0.0502  0.6795  0.0022 
O:  0.7231  0.5530  0.6565 
O:  0.7639  0.5366  0.1578 
O:  0.5441  0.7024  0.9136 
O:  0.1826  0.6363  0.5352 
H:  0.0966  0.7069  0.4998 
H:  0.3073  0.6503  0.7012 
Ca:  0.4320  0.8798  0.7639 
As:  0.7801  0.8791  0.4297 
O:  0.0502  0.8205  0.5022 
O:  0.7231  0.9470  0.1565 
O:  0.7639  0.9634  0.6578 
O:  0.5441  0.7976  0.4136 
O:  0.1826  0.8637  0.0352 
H:  0.0966  0.7931  0.9998 
H:  0.3073  0.8497  0.2012 
Ca:  0.5680  0.3798  0.7361 
As:  0.2199  0.3791  0.0703 
O:  0.9498  0.3205  0.9978 
O:  0.2769  0.4470  0.3435 
O:  0.2361  0.4634  0.8422 
O:  0.4559  0.2976  0.0864 
O:  0.8174  0.3637  0.4648 
H:  0.9034  0.2931  0.5002 
H:  0.6927  0.3497  0.2988 
Atom type  X  Y  Z 

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.
   

Dielectric Properties 


We define:

  • The Born effective charges, also called dynamical charges, are tensors that correspond to the energy derivative with respect to atomic displacements and electric fields or, equivalently, to the change in atomic force due to an electric field: The sum of the Born effective charges of all nuclei in one cell must vanish, element by element, along each of the three directions of the space.
  • The dielectric tensors are the energy derivative with respect to two electric fields. They also relate the induced polarization to the external electric field.

Born effective charges (Z): 

Ca: 2.4140 -0.0347 0.0298 
-0.1223 2.2749 -0.1743 
-0.0102 -0.0010 2.3040 
Eig. Value: 2.4642 2.1869 2.3417 
Mg: 2.0081 0.0469 -0.1412 
0.2577 2.0596 0.1371 
-0.1546 -0.0563 2.4323 
Eig. Value: 1.8457 2.1754 2.4790 
As: 3.3724 0.0706 -0.0047 
-0.0276 3.0526 -0.0195 
0.1002 0.0803 3.1256 
Eig. Value: 3.3835 3.0416 3.1255 
O: -2.0085 0.5391 -0.3187 
0.4939 -1.8204 0.1005 
-0.3227 0.1090 -1.1862 
Eig. Value: -2.5141 -1.4347 -1.0663 
O: -1.3888 -0.1106 0.1167 
-0.0749 -1.5762 0.3752 
0.0801 0.3762 -2.0725 
Eig. Value: -1.3372 -1.4067 -2.2935 
O: -1.4691 0.0414 0.1536 
0.1187 -1.5677 -0.4314 
0.1732 -0.4059 -1.8803 
Eig. Value: -1.4303 -1.2724 -2.2143 
O: -1.9278 -0.3127 -0.1755 
-0.4169 -1.6861 -0.0975 
-0.2384 -0.0505 -1.4215 
Eig. Value: -2.2457 -1.4602 -1.3296 
O: -1.4334 -0.2429 -0.3636 
-0.2220 -1.7342 -0.1070 
-0.2069 -0.0430 -1.3936 
Eig. Value: -1.5076 -1.9458 -1.1078 
H: 0.5515 0.7134 0.0602 
0.4847 1.6679 0.1828 
0.0444 0.2081 0.3654 
Eig. Value: 0.2769 1.9537 0.3542 
H: 0.8856 -0.2324 0.5729 
-0.1243 0.3595 -0.0457 
0.4576 -0.1333 0.9429 
Eig. Value: 0.4386 0.2870 1.4623 
Ca: 2.4140 0.0347 0.0298 
0.1223 2.2749 0.1743 
-0.0102 0.0010 2.3040 
Eig. Value: 2.4642 2.1869 2.3417 
Mg: 2.0081 -0.0469 -0.1412 
-0.2577 2.0596 -0.1371 
-0.1546 0.0563 2.4323 
Eig. Value: 1.8457 2.1754 2.4790 
As: 3.3724 -0.0706 -0.0047 
0.0276 3.0526 0.0195 
0.1002 -0.0803 3.1256 
Eig. Value: 3.3835 3.0416 3.1255 
O: -2.0085 -0.5391 -0.3187 
-0.4939 -1.8204 -0.1004 
-0.3227 -0.1090 -1.1862 
Eig. Value: -2.5141 -1.4347 -1.0662 
O: -1.3888 0.1106 0.1167 
0.0749 -1.5762 -0.3752 
0.0801 -0.3762 -2.0725 
Eig. Value: -1.3372 -1.4067 -2.2935 
O: -1.4691 -0.0414 0.1536 
-0.1187 -1.5677 0.4314 
0.1732 0.4059 -1.8803 
Eig. Value: -1.4303 -1.2724 -2.2144 
O: -1.9278 0.3127 -0.1755 
0.4169 -1.6861 0.0975 
-0.2384 0.0505 -1.4215 
Eig. Value: -2.2457 -1.4602 -1.3296 
O: -1.4334 0.2429 -0.3636 
0.2220 -1.7342 0.1070 
-0.2069 0.0430 -1.3936 
Eig. Value: -1.5076 -1.9458 -1.1078 
H: 0.5515 -0.7134 0.0602 
-0.4847 1.6679 -0.1828 
0.0444 -0.2081 0.3654 
Eig. Value: 0.2769 1.9537 0.3542 
H: 0.8856 0.2324 0.5729 
0.1243 0.3595 0.0457 
0.4576 0.1333 0.9429 
Eig. Value: 0.4386 0.2870 1.4623 
Ca: 2.4140 -0.0347 0.0298 
-0.1223 2.2749 -0.1743 
-0.0102 -0.0010 2.3040 
Eig. Value: 2.4642 2.1869 2.3417 
As: 3.3724 0.0706 -0.0047 
-0.0276 3.0526 -0.0195 
0.1002 0.0803 3.1256 
Eig. Value: 3.3835 3.0416 3.1255 
O: -2.0085 0.5391 -0.3187 
0.4939 -1.8204 0.1005 
-0.3227 0.1090 -1.1862 
Eig. Value: -2.5141 -1.4347 -1.0663 
O: -1.3888 -0.1106 0.1167 
-0.0749 -1.5762 0.3752 
0.0801 0.3762 -2.0725 
Eig. Value: -1.3372 -1.4067 -2.2935 
O: -1.4691 0.0414 0.1536 
0.1187 -1.5677 -0.4314 
0.1732 -0.4059 -1.8803 
Eig. Value: -1.4303 -1.2724 -2.2143 
O: -1.9278 -0.3127 -0.1755 
-0.4169 -1.6861 -0.0975 
-0.2384 -0.0505 -1.4215 
Eig. Value: -2.2457 -1.4602 -1.3296 
O: -1.4334 -0.2429 -0.3636 
-0.2220 -1.7342 -0.1070 
-0.2069 -0.0430 -1.3936 
Eig. Value: -1.5076 -1.9458 -1.1078 
H: 0.5515 0.7134 0.0602 
0.4847 1.6679 0.1828 
0.0444 0.2081 0.3654 
Eig. Value: 0.2769 1.9537 0.3542 
H: 0.8856 -0.2324 0.5729 
-0.1243 0.3595 -0.0457 
0.4576 -0.1333 0.9429 
Eig. Value: 0.4386 0.2870 1.4623 
Ca: 2.4140 0.0347 0.0298 
0.1223 2.2749 0.1743 
-0.0102 0.0010 2.3040 
Eig. Value: 2.4642 2.1869 2.3417 
As: 3.3724 -0.0706 -0.0047 
0.0276 3.0526 0.0195 
0.1002 -0.0803 3.1256 
Eig. Value: 3.3835 3.0416 3.1255 
O: -2.0085 -0.5391 -0.3187 
-0.4939 -1.8204 -0.1004 
-0.3227 -0.1090 -1.1862 
Eig. Value: -2.5141 -1.4347 -1.0662 
O: -1.3888 0.1106 0.1167 
0.0749 -1.5762 -0.3752 
0.0801 -0.3762 -2.0725 
Eig. Value: -1.3372 -1.4067 -2.2935 
O: -1.4691 -0.0414 0.1536 
-0.1187 -1.5677 0.4314 
0.1732 0.4059 -1.8803 
Eig. Value: -1.4303 -1.2724 -2.2144 
O: -1.9278 0.3127 -0.1755 
0.4169 -1.6861 0.0975 
-0.2384 0.0505 -1.4215 
Eig. Value: -2.2457 -1.4602 -1.3296 
O: -1.4334 0.2429 -0.3636 
0.2220 -1.7342 0.1070 
-0.2069 0.0430 -1.3936 
Eig. Value: -1.5076 -1.9458 -1.1078 
H: 0.5515 -0.7134 0.0602 
-0.4847 1.6679 -0.1828 
0.0444 -0.2081 0.3654 
Eig. Value: 0.2769 1.9537 0.3542 
H: 0.8856 0.2324 0.5729 
0.1243 0.3595 0.0457 
0.4576 0.1333 0.9429 
Eig. Value: 0.4386 0.2870 1.4623 
Atom type  X  Y  Z 

Dielectric tensors: 

 X Y Z 
Ɛ∞: 2.9681 0.0000 0.0407 
0.0000 2.9221 0.0000 
0.0407 0.0000 2.8690 
Eig. Value: 2.9827 2.9221 2.8545 
Refractive index (N): 1.7228 0.0000 0.2018 
0.0000 1.7094 0.0000 
0.2018 0.0000 1.6938 
Eig. Value: 1.7270 1.7094 1.6895 
Ɛ0: 0.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
0.0000 0.0000 0.0000 
Eig. Value: 0.0000 0.0000 0.0000