121Sb nuclear gamma-ray resonance study of crystal chemical structures in U---Sb---O acrylonitrile catalysts

Abstract

121Sb Nuclear-gamma-ray resonance measurements have been made at 77 [deg]K on USb2O10, USbO5 and on a commerical supported catalyst preparation 60 wt% USb4.6Ox-40 wt% SiO2. The NGR spectrum of USbO5 is consistent with a single Sb site. The spectrum of USb3O10 is interpreted as resulting from more than one Sb site. In both materials, the covalency of the Sb sites is greater than that in pure Sb---O phases such as Sb2O4 and Sb2O5. The NGR data are consistent with both USbO5 and USb3O10 being catalytically active and with previous conclusions based on kinetic data that differences in the selectivity of USbO5 and USb3O10 result from differences in atomic topologies and geometries.