Crystal Structural Change and Disorder of Bismuth Oxide

抄録

Structural change of bismuth oxide (Bi₂O₃) was studied in situ by high-temperature neutron and synchrotron powder diffraction techniques. The alpha-delta phase transition of Bi₂O₃ was confirmed between 994 and 1013K. Crystal structure was refined by Rietveld method. The lattice parameters, a, b, c and unit-cell volume V of Bi₂O₃ almost linearly increased and beta angle decreased with an increase of temperature. The nuclear density distribution of delta-Bi₂O₃ measured at 1051K was obtained by the maximum entropy method(MEM).Then MEM-based pattern fitting was performed to study the accurate nuclear density distribution of delta-Bi₂O₃. The position of oxygen atoms distributed forming a shape like tetrahedra.