Champ de forces de symetrie locale des composés oxyfluorés du phosphore (V)—I. Les difluorodioxophosphates (DFP) alcalins

Abstract

-Alkali phosphorofluoridates (DFP) were prepared by reaction between phosphoryl difluoride oxide P20~F4 and alkali fluorides. The caesium salt was obtained by reaction between HPO2F2 and caesium chloride. The aim was to establish a coherent description of the various vibrational modes of the PO2F2- ion, so as to use it for more complex molecules involving either of the PO2 and PF2 groups. For that purpose a local symmetric force field (LSFF) was chosen and good agreement found between calculated and observed frequencies. This investigation provided force constant values for the PO2F2- ion in RbPO;F2, and enabled us to test the transferability of the force field to the DFP whose cristallographic structures are known.