FORMATION OF CUBIC DEFINED SM-SN PYROCHLORE STRUCTURES - APPLICATION TO OCM

A series of Sm-Sn pyrochlores were synthesized from propionic acid sol utions of Sm2O3, SnCl2 and BaCO3. The addition of increasing amounts o f water during preparation is shown to influence the BaCl2 precipitati on and the nature of the Sm, Sn containing species remaining in the so lution. The mastership on this parameter permits the synthesis of dope d Sm-Sn pyrochlores with well-known contents of barium and chlorine. T he changes in conversion and C-2 selectivity observed in the oxidative coupling reaction is interpreted in the light of a better knowledge o f the preparation procedure (species present on the surface and in the bulk).