Difference between revisions of "Integral reflection conditions"
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BrianMcMahon (talk | contribs) (The selection rules for Obverse and Reverse setting for the Rhombehedrally centered cell were the wrong way round. Email from Alex Hubert; confirmed by Mois Aroyo.) |
(→Definition: D centred cell) |
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| − | < | + | <font color="blue">Conditions de réflexion intégrales</font> (''Fr''). <font color="red">Integrale Auslöschungen</font> (''Ge''). <font color="green">Ausencias integrales</font> (''Sp''). |
== Definition == | == Definition == | ||
| − | The integral reflections are the general [[reflection conditions]] | + | The integral reflections are the general [[reflection conditions]] appearing when a [[centred lattices|multiple (non-primitive) cell]] is used to describe the [[Bravais lattice]] of a crystal. They are given in the table below: |
<table border cellspacing=0 cellpadding=5 align=center> | <table border cellspacing=0 cellpadding=5 align=center> | ||
<caption align=top> '''Integral reflection conditions for centred lattices.''' </caption> | <caption align=top> '''Integral reflection conditions for centred lattices.''' </caption> | ||
<tr align=left> | <tr align=left> | ||
| − | <th> Reflection<br> condition </th> | + | <th>Reflection<br> condition </th> |
| − | <th> Centring type of cell </th> | + | <th>Centring type of cell </th> |
<th>Centring symbol</th> | <th>Centring symbol</th> | ||
</tr> | </tr> | ||
| Line 45: | Line 45: | ||
<tr align=left> | <tr align=left> | ||
<td> ''h'' − ''k'' = 3''n''</td> <td>hexagonally centred</td> <td> ''H''</td></tr> | <td> ''h'' − ''k'' = 3''n''</td> <td>hexagonally centred</td> <td> ''H''</td></tr> | ||
| + | <tr align=left> | ||
| + | <td> ''h'' + ''k'' + ''l'' = 3''n''</td> <td>D centred</td> <td> ''D''</td></tr> | ||
</table> | </table> | ||
==See also == | ==See also == | ||
| − | + | *Chapter 2.1.3.13 of ''International Tables for Crystallography, Volume A'', 6th edition | |
| − | |||
[[Category:X-rays]]<br> | [[Category:X-rays]]<br> | ||
Latest revision as of 12:59, 27 August 2018
Conditions de réflexion intégrales (Fr). Integrale Auslöschungen (Ge). Ausencias integrales (Sp).
Definition
The integral reflections are the general reflection conditions appearing when a multiple (non-primitive) cell is used to describe the Bravais lattice of a crystal. They are given in the table below:
| Reflection condition |
Centring type of cell | Centring symbol |
|---|---|---|
| None | Primitive | P R (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 k + l = 2n or: | 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 |
| h + k + l = 3n | D centred | D |
See also
- Chapter 2.1.3.13 of International Tables for Crystallography, Volume A, 6th edition