Mössbauer investigation on the crystal field splitting of Fe ion in zinc fluosilicate

The Mössbauer quadrupole interaction ΔE_Q of the Fe²⁺ ion has been measured with 2% at. ⁵⁷Fe in ZnSiF₆·6H₂O, between 1.3 and 20°K. The sign of ΔE_Q (< 0) has been determined by using a single crystal absorber. These results are interpreted in terms of a trigonal crystal field potential that splits the Fe²⁺ orbitals into a ground state singlet and a first excited doublet whose distance is much smaller than that reported for FeSiF₆·6H₂O, in reasonable agreement with previous EPR measurements.