Analysis of Ground-State Zero-Field Splitting for Mn2+ in ZnNbOF5?6(H2O) and CoNbOF5?6(H2O)

The electron paramagnetic resonance spectra of trigonal Mn2+ centers in ZnNbOF5?6(H2O) and CoNbOF5?6(H2O) crystals are studied on the basis of the complete energy matrices for a d5 configuration ion in a trigonal ligand field. It is demonstrated that the local lattice structure around a trigonal Mn2+ center has an elongation distortion along the crystalline c3 axis, and when Mn2+ is doped in the ZnNbOF5?6(H2O) and CoNbOF5?6(H2O) crystals, there is a similar local distortion. From the EPR calculation, the local lattice structure parameters for trigonal Mn2+ centers in ZnNbOF5?6(H2O) and CoNbOF5?6(H2O) are determined.