# Integral reflection conditions

### From Online Dictionary of Crystallography

Conditions de réflexion intégrales (*Fr*).

## Definition

The integral reflections are the general reflection conditions due to the centring of cells. They are given in the table below:

Reflection condition |
Centring type of cell | Centring symbol |
---|---|---|

None | Primitive | PR (rhombohedral axes) |

h + k = 2n | C-face centred | C |

k + l = 2n | A-face centred | A |

l + h = 2n | B-face centred | B |

h + k + l = 2n | body centred | I |

h + k, h + l and
| all-face centred | F |

− h + k + l = 3n | rhombohedrally centred, obverse |
R (hexagonal axes) |

h − k + l = 3n | rhombohedrally centred, reverse | |

h − k = 3n | hexagonally centred | H |

## See also

- Section 2.1.3.13 of
*International Tables of Crystallography, Volume A*, 6^{th}edition