Most of the AIIIBVsemiconducting compounds have the zincblende crystal structure. This structure is noncentrosymmetric and as a consequence the modulii ofF(hkl) andF(h¯k¯l¯), the geometrical structure factors, have different magnitudes. This difference results in a variation in the integrated intensities of certain x‐ray reflection from opposite sides of samples taken from crystals with the zincblende structure. X‐ray measurements of a series of {111} reflections from opposite sides of an InAs single crystal have been made and related to the etching characteristics of these surfaces.