-    ALACRANITE     -    As8S9

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:  13  P2/c 
Lattice parameters (Å):  5.2611  5.0806  4.8568 
Angles (°):  90.0  101.9  90.0 

Symmetry (theoretical): 

Space group:  13  P2/c 
Lattice parameters (Å):  10.6501  8.2818  9.7402 
Angles (°):  90.0  93.9  90.0 

Cell contents: 

Number of atoms:  34 
Number of atom types:  2 
Chemical composition:  0 

Atomic positions (theoretical):

As:  0.0479  0.2673  0.9301 
As:  0.1610  0.4853  0.7963 
As:  0.4226  0.3429  0.4253 
As:  0.3930  0.9992  0.1846 
S:  0.0000  0.1012  0.7500 
S:  0.0000  0.6571  0.7500 
S:  0.1438  0.3839  0.5781 
S:  0.2931  0.1462  0.3371 
S:  0.5000  0.4887  0.2500 
S:  0.4132  0.1780  0.0112 
As:  0.9521  0.2673  0.5699 
As:  0.8390  0.4853  0.7037 
As:  0.5774  0.3429  0.0747 
As:  0.6070  0.9992  0.3154 
S:  0.8562  0.3839  0.9219 
S:  0.7069  0.1462  0.1629 
S:  0.5868  0.1780  0.4888 
As:  0.9521  0.7327  0.0699 
As:  0.8390  0.5147  0.2037 
As:  0.5774  0.6571  0.5747 
As:  0.6070  0.0008  0.8154 
S:  0.0000  0.8988  0.2500 
S:  0.0000  0.3429  0.2500 
S:  0.8562  0.6161  0.4219 
S:  0.7069  0.8538  0.6629 
S:  0.5000  0.5113  0.7500 
S:  0.5868  0.8220  0.9888 
As:  0.0479  0.7327  0.4301 
As:  0.1610  0.5147  0.2963 
As:  0.4226  0.6571  0.9253 
As:  0.3930  0.0008  0.6846 
S:  0.1438  0.6161  0.0781 
S:  0.2931  0.8538  0.8371 
S:  0.4132  0.8220  0.5112 
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): 

As: 0.8048 -0.4652 -0.0122 
0.0101 0.8700 0.6623 
-0.2951 1.3832 1.7597 
Eig. Value: 0.7850 0.1806 2.4688 
As: 1.2917 -0.1774 -0.2527 
-0.0556 0.4588 0.4524 
-0.1115 0.9969 2.4405 
Eig. Value: 1.2636 0.2193 2.7082 
As: 2.0025 -0.0650 0.1852 
-0.2557 2.2274 -0.1816 
0.1809 -0.9324 1.7403 
Eig. Value: 1.9275 2.6740 1.3687 
As: 0.4315 -0.1911 -0.8308 
-0.6261 0.9737 0.4803 
-1.0001 0.2879 1.8869 
Eig. Value: -0.0545 0.8376 2.5091 
S: -0.9916 0.0000 0.0133 
0.0000 -1.1279 0.0000 
-0.1340 0.0000 -2.0802 
Eig. Value: -0.9882 -1.1279 -2.0835 
S: -1.1219 -0.0000 -0.1918 
-0.0000 -0.4996 -0.0000 
0.5386 -0.0000 -0.5489 
Eig. Value: -1.1703 -0.4996 -0.5005 
S: -1.0165 -0.0261 0.1033 
-0.1242 -0.7406 -0.0910 
0.2809 0.3402 -1.7750 
Eig. Value: -0.9781 -0.7156 -1.8384 
S: -0.8210 0.2386 0.1604 
0.1423 -1.5310 -0.4417 
0.1892 -0.5617 -1.8350 
Eig. Value: -0.7700 -1.1647 -2.2523 
S: -0.9106 0.0000 1.0503 
-0.0000 -1.1431 0.0000 
0.6230 -0.0000 -2.7569 
Eig. Value: -0.5878 -1.1431 -3.0796 
S: -1.1810 -0.6382 0.2109 
0.0143 -0.8730 0.1531 
0.2420 0.3112 -1.5244 
Eig. Value: -1.1310 -0.6706 -1.7767 
As: 0.8048 0.4652 -0.0122 
-0.0101 0.8700 -0.6623 
-0.2951 -1.3832 1.7597 
Eig. Value: 0.7850 0.1806 2.4688 
As: 1.2917 0.1774 -0.2527 
0.0556 0.4588 -0.4524 
-0.1115 -0.9969 2.4405 
Eig. Value: 1.2636 0.2193 2.7082 
As: 2.0025 0.0650 0.1852 
0.2557 2.2274 0.1816 
0.1809 0.9324 1.7403 
Eig. Value: 1.9275 2.6740 1.3687 
As: 0.4315 0.1911 -0.8308 
0.6261 0.9737 -0.4803 
-1.0001 -0.2879 1.8869 
Eig. Value: -0.0545 0.8376 2.5091 
S: -1.0165 0.0261 0.1033 
0.1242 -0.7406 0.0910 
0.2809 -0.3402 -1.7750 
Eig. Value: -0.9781 -0.7156 -1.8384 
S: -0.8210 -0.2386 0.1604 
-0.1423 -1.5310 0.4417 
0.1892 0.5617 -1.8350 
Eig. Value: -0.7700 -1.1647 -2.2523 
S: -1.1810 0.6382 0.2109 
-0.0143 -0.8730 -0.1531 
0.2420 -0.3112 -1.5244 
Eig. Value: -1.1310 -0.6706 -1.7767 
As: 0.8048 -0.4652 -0.0122 
0.0101 0.8700 0.6623 
-0.2951 1.3832 1.7597 
Eig. Value: 0.7850 0.1806 2.4688 
As: 1.2917 -0.1774 -0.2527 
-0.0556 0.4588 0.4524 
-0.1115 0.9969 2.4405 
Eig. Value: 1.2636 0.2193 2.7082 
As: 2.0025 -0.0650 0.1852 
-0.2557 2.2274 -0.1816 
0.1809 -0.9324 1.7403 
Eig. Value: 1.9275 2.6740 1.3687 
As: 0.4315 -0.1911 -0.8308 
-0.6261 0.9737 0.4803 
-1.0001 0.2879 1.8869 
Eig. Value: -0.0545 0.8376 2.5091 
S: -0.9916 -0.0000 0.0133 
-0.0000 -1.1279 -0.0000 
-0.1340 -0.0000 -2.0802 
Eig. Value: -0.9882 -1.1279 -2.0835 
S: -1.1219 -0.0000 -0.1918 
0.0000 -0.4996 0.0000 
0.5386 0.0000 -0.5489 
Eig. Value: -1.1703 -0.4996 -0.5005 
S: -1.0165 -0.0261 0.1033 
-0.1242 -0.7406 -0.0910 
0.2809 0.3402 -1.7750 
Eig. Value: -0.9781 -0.7156 -1.8384 
S: -0.8210 0.2386 0.1604 
0.1423 -1.5310 -0.4417 
0.1892 -0.5617 -1.8350 
Eig. Value: -0.7700 -1.1647 -2.2523 
S: -0.9106 0.0000 1.0503 
0.0000 -1.1431 -0.0000 
0.6230 0.0000 -2.7569 
Eig. Value: -0.5878 -1.1431 -3.0796 
S: -1.1810 -0.6382 0.2109 
0.0143 -0.8730 0.1531 
0.2420 0.3112 -1.5244 
Eig. Value: -1.1310 -0.6706 -1.7767 
As: 0.8048 0.4652 -0.0122 
-0.0101 0.8700 -0.6623 
-0.2951 -1.3832 1.7597 
Eig. Value: 0.7850 0.1806 2.4688 
As: 1.2917 0.1774 -0.2527 
0.0556 0.4588 -0.4524 
-0.1115 -0.9969 2.4405 
Eig. Value: 1.2636 0.2193 2.7082 
As: 2.0025 0.0650 0.1852 
0.2557 2.2274 0.1816 
0.1809 0.9324 1.7403 
Eig. Value: 1.9275 2.6740 1.3687 
As: 0.4315 0.1911 -0.8308 
0.6261 0.9737 -0.4803 
-1.0001 -0.2879 1.8869 
Eig. Value: -0.0545 0.8376 2.5091 
S: -1.0165 0.0261 0.1033 
0.1242 -0.7406 0.0910 
0.2809 -0.3402 -1.7750 
Eig. Value: -0.9781 -0.7156 -1.8384 
S: -0.8210 -0.2386 0.1604 
-0.1423 -1.5310 0.4417 
0.1892 0.5617 -1.8350 
Eig. Value: -0.7700 -1.1647 -2.2523 
S: -1.1810 0.6382 0.2109 
-0.0143 -0.8730 -0.1531 
0.2420 -0.3112 -1.5244 
Eig. Value: -1.1310 -0.6706 -1.7767 
Atom type  X  Y  Z 

Dielectric tensors: 

 X Y Z 
Ɛ∞: 6.1684 0.0000 -0.6248 
0.0000 6.2555 0.0000 
-0.6248 0.0000 7.4758 
Eig. Value: 5.9178 6.2555 7.7264 
Refractive index (N): 2.4836 -0.0000 -0.7905 
-0.0000 2.5011 -0.0000 
-0.7905 -0.0000 2.7342 
Eig. Value: 2.4327 2.5011 2.7796 
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