Etude de la solution solide Pb2O(S1?xWxO4) et structure cristalline de la variete alpha du monooxodiplomb (II) tetraoxotungstate (VI) Pb2O(WO4) par diffraction X sur poudres

The Pb₂O(S_1?xW_xO₄) solid solution has been investigated by X-ray diffraction in the 0<x<1 range. Direct synthesis of monooxodilead(II)tetraoxotungstate(VI) by heating 2PbO+WO₃ mixtures at different temperatures, reveals the existence of two polymorphs: alpha-Pb₂ O(WO₄) is obtained for 823<T<833K and beta-Pb₂ O(WO₄) for T>1073K. For 833<T<1073K, mixtures of both polymorphs are obtained. In the present work the alpha-Pb₂O(WO₄) species is characterized for the first time, and crystal structure investigations by X-ray diffraction on polycristalline samples show that this phase is isostructural with its Pb₂O(AO₄) homologues for A = S, Cr and Mo (1).