Redetermination of the crystal structure of alpha -Bi sub(2)O sub(3).3MoO sub(3) by neutron diffraction and the catalytic oxidation of propene

The powder profile obtained by neutron diffraction was analysed by the Rietveld method. The catalytic oxidation of propene over alpha -Bi sub(2)O sub(3).3MoO sub(3) is examined. The high activity is related to the fact that the principal cleavage plane contains together Bi and Mo ions. On the contrary gamma -Bi sub(2)O sub(3).MoO sub(3) is less active, probably because only small faces are active. The lone pairs disposition is not favorable to oxygen ionic conductivity; this rather low conductivity may favor a rather high selectivity in acrolein.