VO2+ doped single crystal of Ba2Zn(HCOO)(6)(H2O)(4) (BZFA) were investigated using electron paramagnetic resonance (EPR) technique at ambient temperature. Detailed investigation of EPR spectra indicated that the VO2+, substitutes the Zn2+ in the structure. The sites with different orientations were observed for VO2+ in Ba2Zn(HCOO)(6)(H2O)(4)center dot single crystal, but the only intense site among these sites was evaluated to obtain spin-Hamiltonian parameters, which are the principal axis values of the g and the hyperfine tensors. The covalent bonding parameter for VO2+ and Fermi contact term were calculated using the spin-Hamiltonian parameters. (c) 2006 Elsevier B.V. All rights reserved.