A new structural model for Pb-deficient PbWO4

Abstract A previously reported structure proposal for Pb-deficient PbWO 4 (Pb 7 W 8 O 32− x , space group P 4/ nnc ) could be rejected based on neutron powder diffraction data. A new model in agreement with X-ray and neutron diffraction data is proposed (tetragonal, tP 48, space group P -4- h 10 g 2 dcba , a =7.7208(1), c =12.0417(2) A). It is a superstructure of the scheelite type with partial vacancies on a one-fold lead site, leading to the composition Pb 7.5 W 8 O 32 .