[en] Short note

[en] The title compound was first prepared in solid state from its aqueous solution by means of the cryogenic method and characterized by chemical and thermal analyses, IR and UV spectroscopy. From X-ray heating patterns the formation of a new cubic phase 1/2 Al₂O₃ · 12 WO₃(I) at 400 ⁰C was found, being stable till 830 ⁰C: a = 378 pm (600 ⁰C). High-resolution ²⁷Al NMR (MAS-technique) was used to determine the tetrahedral coordination of aluminium in the title compound and the octahedral coordination in I. The degradation of the doped WO₃-phase I into Al₂(WO₄)₃ begins at 600 ⁰C. Above 830⁰C tetragonal WO₃ and Al₂(WO₄)₃ coexist. (author)