EPR OF MN2-ION-DOPED SINGLE-CRYSTALS OF MG[C4H3O4](2)CENTER-DOT-6H2O()

Electron paramagnetic resonance of Mn2+-ion-doped single crystals of m agnesium bis(hydrogen maleate) hexahydrate, Mg[C4H3O4](2) . 6H(2)O, ha s been studied at room and liquid nitrogen temperatures using X-band f requencies. Two differently oriented but otherwise identical complexes of Mn2+ ions are found in these crystals. From the observed EPR spect ra, spin-Hamiltonian parameters were calculated. It was found that the Mn2+ ions substitute for ions. The observed negative shift in g(paral lel to)-value of Mn2+ at room temperature may be due to the polarizati on effects of the host Mg2+ ions which produce a local static magnetic field at the Mn2+ sites. The observation of resolved Mn2+ spectra at room temperature and its broadening on lowering the temperature in Mg( C4H3O4). 6H(2)O:Mn2+ single crystals has been explained. The percentag e of covalency in the Mn-O bond has been estimated to be 8%. (C) 1997 Elsevier Science B.V.