An EPR study of various compounds of copper (II) and silver (II)

Abstract

The electron paramagnetic resonance (EPR) spectra in the three-centimeter and decimeter wavelength ranges have been studied in liquid and frozen solutions of copper(II) and silver(II) in ortho-, pyro-, and metaphosphoric acids, sulfuric acid, and nitric acid, and also in liquid and frozen solutions of Cu(II) in fluorosilicic acid. The parameters of the spin Hamiltonian have been determined. It has been shown that the magnetic ion M(II) in these compounds is situated in an axially distorted octahedron, formed by six oxygen atoms. The EPR spectra of frozen solutions of M(II) in ortho-, pyro-, and metaphosphoric acids, obtained by the procedure described in the present paper, do not differ from one another. Study of the EPR spectra over a wide range of frequencies has shown that for the Cu(II) compounds the condition of strong fields is satisfied as far as 800–1000 MHz, but on going to lower frequencies the condition of intermediate fields is satisfied. For the Ag(II) compounds the condition of strong fields is satisfied throughout the entire range of frequencies studied. It can be seen from the experimental results obtained that the values of the anisotropic hyperfine splitting (HFS) constants, reduced to unit magnetic moment of the corresponding nuclei, increase on going from the Cu(II) ions with n=3 to the Ag(II) ions with larger principal quantum number (n=4).