Centric and acentric distribution

Definition

Centric or acentric distribution usually refer to the X-ray diffracted intensity distribution. It is in general possible to distinguish between a centrosymmetric or a non-centrosymmetric space group by considering their intensity distribution. The figure below represents the theoretical cumulative intensity curves for the acentric, centric and hypercentric-distributions as fraction of the means intensity

In practice, it is not always possible to clearly distinguish between a centric and an acentric distribution. This is specifically the case for inorganic material with highly symmetric structures.

See also

Wilson, A. J. C. (1949). The probability distribution of X-ray intensities. Acta Cryst. 2, 318-321.