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Electron paramagnetic resonance (EPR) and optical studies of VO(II) doped cadmium sodium sulphate hexahydrate (CSSH) are carried out at room temperature. The EPR spectra, recorded in the three orthogonal planes, indicate that the paramagnetic impurity has entered the lattice site both in substitutional and interstitial positions. The spin Hamiltonian parameters, calculated from the spectra for the two sites, are: site I: gxx=1.984, gyy=1.975, gzz=1.938; Axx=6.56, Ayy=7.50, Azz=18.61 mT; site II: gxx=1.982, gyy=1.978, gzz=1.940; Axx=6.88, Ayy=7.56, Azz=18.57 mT. The EPR spectrum of the powder sample also reveals the presence of two sites in the host lattice, suggesting that the two sites are chemically and magnetically inequivalent. The optical absorption spectrum exhibits three characteristic bands. Crystal field, tetragonal field, admixture coefficients and bonding parameters are evaluated, which suggest that the complex is fairly covalent in nature.

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Single crystal Electron Paramagnetic Resonance studies on Mn(II) doped cadmium ammonium phosphate hexahydrate were carried out at room temperature. The angular variation spectra of the crystal in three orthogonal planes show that the paramagnetic impurity Mn(II) has entered the host lattice substitutionally. The spin Hamiltonian parameters calculated from the EPR data are g = 2.002, A = 9.25 mT, D = 32.7 mT, a = 0.3 mT and F = 0.6 mT. These Hamiltonian parameter values (g, A and D) match fairly well with those calculated from the powder spectrum. The percentage covalency of Mn-O bond has been estimated to be 8.5.

Single crystal electron paramagnetic resonance studies on VO(II) doped cadmium ammonium phosphate hexahydrate were carried out at room temperature. The paramagnetic impurity VO(II) was found to enter the host lattice both substitutionally and interstitially. The spin Hamiltonian parameter values calculated from crystal rotations for both the locations are; Site1: g∥ = 1.939, g⟂ = 1.992, A∥ = 16.3mT, A⟂ = 7.7mT and site2: g∥ = 1.933, g⟂ = 1.998, A∥ = 16.2mT, A⟂ = 7.7mT. The powder spectra values agree well with the single crystal data. The two sites have been identified as at right angles to each other. The admixture coefficients and other parameter values (κ and P) were evaluated from the spin Hamiltonian parameters. The complex was found to be fairly covalent in nature.

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