The Symmetry Principle in Crystal Chemistry

In crystalline solids a tendency to form arrangements of high symmetry is observable. The symmetry principle, put forward in this form by F. Laves, has been stated in a more exact manner by H. Barnighausen  

In the solid state the arrangement of atoms shows a pronounced tendency towards the highest possible symmetry. 

Counteracting properties of the atoms or atom aggregates may prevent the attainment of the highest possible symmetry, but in most cases the deviations from the ideal symmetry are only small (keyword pseudosymmetry). 

During a phase transition or a reaction in the solid state which results in one or more products of lower symmetry, very often the higher symmetry of the starting material is indirectly preserved by the orientation of domains formed within the crystalline matrix. 

Atoms of the same kind tend to be in equivalent positions. 

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