The microstructural and luminescent properties of H1.77[Sr0.8Bi0.21Ta2O7] powders under different dehydrating conditions were investigated. The powders were obtained by protonating Bi2SrTa2O9 powders in 3 M aqueous HCl solution, and were dehydrated by a post-annealing in air from 250 to 700 degrees C. The photoluminescence was enhanced for all dehydrated powders, especially for the sample annealed at 400 degrees C. The thermogravimetric analysis showed that there is an obvious dehydration temperature range from 200 to 400 degrees C, which was corresponding to the changing of the microstructure and photoluminescence in the same temperature range. The mechanism behind the experimental results was discussed. (C) 2010 Elsevier Ltd. All rights reserved.