PRECISION X-RAY-DIFFRACTION STUDY OF THE GARNETS NA3SC2V3O12 AND NA0.90CA2.38MN1.72V3O12

The distribution of electron density and electrostatic potential in the compounds Na3Sc2V3O12 (ScVG) and Na0.90Ca2.38Mn1.72V3O12 (MnVG) with garnet structure was studied by precision x-ray diffraction. Refinement of the structure using reflections chosen by a special method from the outer region of reciprocal space led to R = 0.0085, R(w) = 0.0071, S = 1.006 (ScVG) and R = 0.0058, R(w) = 0.0049, S = 1.079 (MnVG). Maps of deformed electron density and deformed electrostatic potential were constructed and their interpretation given in terms of MO. Features of the electronic structure in the crystals studied have a confidence level not lower than 95%.