Comments on Divalent-Fe57mQuadrupolar Coupling Constants

The quadrupolar coupling constant for divalent ${\mathrm{Fe}}^{57m}$ in FeSi${\mathrm{F}}_6$·6${\mathrm{H}}_2$O is recalculated and compared with that in other compounds. One finds a correlation between the isomer shift and $〈\frac{1}{r^3}〉$ parameters brought on by covalency effects.