The theory of the Huang scattering of point defects in hexagonal crystals was considered. The concept of so-called elementary defects, which was based upon group theoretical methods, was introduced. It was concluded that point defects in hexagonal crystals could be understood as being unique superpositions of 3 types of incoherent elementary scattering defect. These elementary defects reflected characteristic defect symmetries. This concept led to a simple analytical expression for the Huang intensity in the case of arbitrary scattering vectors.

T.Michelitsch, A.Wunderlin: Physica Status Solidi B, 1996, 198[2], 615-20