Vanadium interatomic distance

The interatomic distances found are V—S = 2.186 0.040 A and Cu—S — 2.285 i 0.014 A. The Cu—S distance is somewhat smaller than the sum of the tetrahedral radii2) for sulfur and univalent copper, 2.39 A. As in the case of chalcopyrite, this probably indicates that the valence states are not well defined as CuIiVvSi, but fluctuate, the copper resonating between cuprous and cupric states and the vanadium between quinquivalent and lower states. 

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