Table 4. Relations for the total length g_xyz, the out-of-plane component g_z and the in-plane component g_xy of the reciprocal-space vectors with indices hkl and of the vector uvw (g _spec) and the volume V in trigonal and hexagonal crystallographic systems.

Trigonal a = b = c, α = β = γ ≠ 90°

Hexagonal a = b ≠ c, α = β = 90°, γ = 120°