Bilbao Crystallographic Server arrow Index of a group-subgroup pair Help

INDEX: Index of a group-subgroup pair


Index of a group-subgroup pair
The program INDEX calculates the index of a group subgroup pair. The index can be calculated in two different ways:
  • Option A

    • The space group ITA numbers.
    • The number of atoms per conventional unit cells.

    The number of atoms per conventional unit cell* Nc is simply related to the number N of atoms per primitive unit cell via the so-called centring factor f, N=Nc/f, with f=1 for primitive lattices, 2 for I-, C-, B-, A- centred, 3 for R-centred and 4 for F-centred lattice.

  • Option B

    • The space group ITA numbers.
    • The lattice parameters.

    In some cases, due to the lattice deformation, the data on the lattice parameters (option B) might not be sufficient for the calculation of the index.

*For us, the conventional cell for rhombohedral groups is the centred cell (hexagonal axes).
Please, enter the sequential number of group as given in International Tables for Crystallography, Vol. A :
Please, enter the sequential number of its subgroup as given in International Tables for Crystallography, Vol. A :

  • Option A: Introduce the number of atoms per conventional unit cell
Number of atoms per conventional unit cell of the high symmetry structure:
Number of atoms per conventional unit cell of the low symmetry structure:

  • Option B: Introduce the lattice parameters
The lattice parameters of the high symmetry structure:
The lattice parameters of the low symmetry structure:




[ Bilbao Crystallographic Server Main Menu ]

Bilbao Crystallographic Server
http://www.cryst.ehu.es		 Licencia de Creative Commons
For comments, please mail to
administrador.bcs@ehu.es