A statistical study on the measurability of Bijvoet differences in crystals with type-I and type-II degree of centrosymmetry

The probability distributions of the normalized Bijvoet differences x and Δ are derived for non-centrosymmetric crystals with type-I and type-II degree of centrosymmetry assuming that there is a single anomalous scatterer in the unit cell besides a sufficiently large number of similar normal scatterers. The theoretical results are used to study the influence of degree of centrosymmetry on the measurability of Bijvoet differences. It is found that, for given values of k and σ²₂, the measurability is in general poorer in the type-I case than in the type-II case.