-    HORNBLENDE-Mg     -    []Ca2Mg4AlSi7AlO22(OH)2

 

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:  P1 
Lattice parameters (Å):       
Angles (°):       

Symmetry (theoretical): 

Space group:  P1 
Lattice parameters (Å):  0.5292  0.5292  0.5292 
Angles (°):  82.71  97.29  57.14 

Cell contents: 

Number of atoms:  41 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Mg:  0.0912  0.0829  0.4986 
Al:  0.1774  0.1702  0.0042 
Mg:  0.0056  0.9956  0.0046 
Ca:  0.2841  0.2748  0.5078 
Al:  0.3702  0.7997  0.3080 
Si:  0.4647  0.8840  0.8233 
O:  0.1946  0.9926  0.2037 
O:  0.2837  0.0578  0.7510 
O:  0.1120  0.8872  0.7156 
O:  0.6036  0.9086  0.7768 
O:  0.5038  0.7900  0.1246 
O:  0.4630  0.7747  0.6240 
O:  0.3354  0.6540  0.2864 
H:  0.2193  0.7863  0.7747 
Si:  0.8071  0.3649  0.6946 
Si:  0.8846  0.4612  0.1828 
O:  0.9842  0.1985  0.7875 
O:  0.0582  0.2861  0.2543 
O:  0.8892  0.1114  0.2837 
O:  0.8852  0.6144  0.2072 
O:  0.7896  0.4873  0.8818 
O:  0.7794  0.4546  0.3953 
O:  0.6663  0.3366  0.7045 
H:  0.7852  0.2156  0.2274 
Mg:  0.9130  0.9095  0.5000 
Mg:  0.8209  0.8271  0.9971 
Ca:  0.7106  0.7271  0.4959 
Si:  0.6354  0.1962  0.6974 
Si:  0.5347  0.1211  0.1851 
O:  0.8053  0.0248  0.7802 
O:  0.7067  0.9508  0.2700 
O:  0.3730  0.1276  0.1863 
O:  0.5137  0.2189  0.8902 
O:  0.5329  0.2276  0.4040 
Si:  0.1949  0.6299  0.3006 
Si:  0.1129  0.5329  0.8124 
O:  0.0221  0.8010  0.2187 
O:  0.9434  0.7067  0.7265 
O:  0.1160  0.3724  0.8042 
O:  0.2065  0.5071  0.1127 
O:  0.2202  0.5302  0.5963 
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.
 

Parameters of the Calculation 


All the calculations have been done using the ABINIT software. This is a list of the most representative parameteres used during the Raman calculation.


Number of electronic bands: 96
k-points  
   grid: 4 4 4 
   number of shifts: 
   shifts: 0.5 0.5 0.5 
Kinetic energy cut-off: 40 Ha  [=1088.464 eV ]
eXchange-Correlation functional: LDA pw90 

Pseudopotentials: 
Mg:  magnesium, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local 
Al:  aluminium, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local 
Ca:  calcium, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 0 local 
Si:  silicon, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local 
O:  oxygen, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local 
H:  hydrogen, fhi98PP : Trouiller-Martins-type, LDA Ceperley/Alder Perdew/Wang (1992), l= 2 local