Mössbauer spectroscopy of KrF2 and KrF2⋅MF5 ( M =As, Sb)

Mössbauer spectra of KrF2 and the recently synthesized compounds α- and β- [KrF]+[AsF6]− and [KrF]+[SbF6]− have been measured using the 9.4 keV transition of 83Kr produced in the decay of an 83RbF source. The results for the values of quadrupole coupling strengths and the isomer shifts indicate that the Kr–F bonding in all compounds studied is very similar. A slight increase of the quadrupole coupling in going from KrF2 to F–Kr–F–MF5 can be interpreted in terms of a shortening of the average Kr–F bond length. A very accurate value, Qex/Qgr=1.958±0.002 for the ratio of the quadrupole moments of the 9.4 keV state and the ground state has also been derived from the measurements.