Exploration of New Bismuth Oxides with Controlled Valence

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We have obtained the following results by hydrothermal reactions using a hydrated sodium bismuth oxide (NaBiO_3・nH_2O) as a strating material.I. When alkaline chromate solution was used, a new compound, CrBi_8O_15 was found and its crystalstructure was determined by using single crystal X-ray diffraction data. The crystal structure hasa slab built up by (CrO_4)^<2-> tetrahedra and bismuth polyhedra formed by coordination of 5 〜 8 oxygen atoms. The distance of lone pair from nucleus for bismuth atoms ranges from 0.53 to 1.32A, depending on the coordination environment.II. Several new bismuth compounds have been obtained when manganese, vanadium molybdenum and tungsten solutions were used. The characterization of these new compounds are under investigation.III. New bismuth oxides are attempted to use as oxidation catalysis.New bismuth compounds were also prepared by using AgBiO_3 which was obtained by hydrothermal reactions using NaBiO_3・nH_2O and these new compounds are tried to solve their crystal structure.New compounds were obtained in the MgO-Nb_2O_5-Bi_2O_3 system by high temperature solid state reactions as well as hydrothermal reactions. The characterization of these new compounds are under investigation.