Definition
The integral reflections are the general reflection conditions due to the centring of cells. They are given in the table below:
Integral reflection conditions for centred lattices.
Reflection condition |
Centring type of cell |
Centring symbol |
None | Primitive | P
R (rhombohedral axes) |
h + k = 2n | C-face centred | C</th>
|
<tr align=left>
<td>k + l = 2n</td> <td>A-face centred</td> <td>A</th>
</tr>
<tr align=left>
<td>l + h = 2n</td> <td>B-face centred</td> <td>B</td>
</tr>
<tr align=left>
<td>h + k + l = 2n</td> <td>body centred</td> <td>I</th>
</tr>
<tr align=left>
<td>h + k, h + l and
k + l = 2n or:
h, k, l all odd or all
even (‘unmixed’)</td> <td>all-face centred</td> <td> F</th>
</tr>
<tr align=left>
<td> − h + k + l = 3n</td> <td> rhombohedrally
centred, reverse
setting </td><td rowspan=2>R (hexagonal axes)</td></tr>
<tr align=left>
<td> h − k + l = 3n</td> <td> rhombohedrally
centred, obverse
setting (standard)</td>
</tr>
<tr align=left>
<td> h − k = 3n</td> <td>hexagonally centred</td> <td> H</td>
</table>