Powder diffraction multiplicity ($m_{hkl}$)

The number of symmetry-equivalent directed reciprocal-lattice normals belonging to a powder-reflection family. For a cubic crystal, $\{111\}$ has multiplicity eight, corresponding to four unoriented plane orientations; hexagonal $002$ has multiplicity two. Multiplicity contributes to integrated powder intensity alongside the structure factor, angular factors and sample-dependent corrections.