Bragg condition  QuasiBragg condition  Comment 
nλ ≈ dΘ  τ^{m}λ ≈ d'Θ'  Including metric, ('), n, m integral m = −infinity, −1, 0 1, 2, 3… or h' = 0, τ^{−1}, 1,τ, τ^{−1}, τ^{−2}, τ^{−3}… 
d = a/h  d' = a'/h'  r is fixed within known models 

 Diffraction depends on harmonic r. h in SF for Equation (1) & QSF for (2) 
c_{s} = 1  c_{s} < 1  In quasi Bragg h' c_{s} < h ${{d}^{\prime}}_{\tau 00}$ = 0.205 ´ c_{s} nm ${{d}^{\prime}}_{100}$ = 0.205 ´ c_{s} ´ τ = 0.296 nm, = a' 