The relative intensities of partial spectral doublets A, B and C, corresponding to three distinct values of q.s., could be referred to three definite atomic configurations Fe - (Fe n Zn 12-n ), just if the Fe2+ and Zn ions are distributed random. When one takes into account, that the symmetric pairs of Zn ions do not disturb the electric field gradient at the central Fe2+ ion, the C-doublet is to be referred to neff = 0, B doublet - to neff = 1 and A doublet to - neff = 2 or more.
The values of q.s. of doublets A, B and C are changing
with composition a little, the isomer shift has the constant value for all doublets and does not depend on the composition. The data presented, at first prove the random distribution of Fe2+ and Zn2+ ions in the sphalerite solid solution FexZn1-xS, at least up to x = 0.32.