Chemical ordering and body-centering extinction
= Chemical ordering and body-centering extinction
Sites at 000 and one half of each cubic coordinate give $F=f_A+(-1)^{h+k+l}f_B$. Identical sites produce a <body-centered cubic lattice> with absent odd-parity reflections. Distinct chemical species generally preserve only the <simple cubic lattice> translations, so those same odd reflections need not vanish. A geometric body center is not by itself a symmetry translation of the decorated crystal.