Single crystal EPR of Cu(C 5H 5NO) 6(BF 4) 2: an example of admixed ground state

Abstract

Single crystal electron paramagnetic resonance (EPR) of Cu(C 5H 5NO) 6(BF 4) 2 is studied at 300 K. The spin Hamiltonian parameters obtained at 300 K are A 11=−149.8, A 22=−50.7 and A 33=−37.7 (all in units of 10 −4 cm −1), g 11=2.3452, g 22=2.0679 and g 33=2.0695. Angular variation of hyperfine structure lines shows the presence of a single magnetic site. The low magnitude of the A 11 value for Cu(C 5H 5NO) 6(BF 4) 2 is rationalized in terms of a mixed d x 2-y 2 d z 2 ground state.