Related Experiment Video
Updated: May 26, 2026

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries
Published on: November 10, 2014
Phase and electrical behaviour in Bi4NbO8.5
M Holdynski1, M Sintyureva, X Liu
1Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland. mholdinski@ichf.edu.pl
Abstract:
A study of phase and electrical behaviour in the bismuth niobate, Bi(4)NbO(8.5), using x-ray and neutron powder diffraction, thermogravimetric analysis (TGA), x-ray photoelectron spectroscopy (XPS) and ac impedance spectroscopy is presented. Two polymorphs were identified in this composition, a tetragonal phase (type III), which can appear at temperatures above 800 °C and a pseudo-cubic phase (type II) evident at lower temperatures. The defect structure analysis of the type II phase is consistent with the existence of chains of niobate polyhedra, which facilitate electronic conduction at low temperatures. The appearance of the type III phase is strongly dependent on experimental conditions and TGA and XPS measurements suggest a likely association with change in oxygen stoichiometry.
More Related Videos
08:12Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
Published on: September 8, 2017
08:00Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain
Published on: March 27, 2018
Related Concept Videos
Phase Diagram
Phase Diagram
Valence Bond Theory
Phase Diagrams
Phase Transitions
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...