Computational prediction and experimental confirmation of rhombohedral structures in Bi_1.5CdM_1.5O₇ (M = Nb, Ta) pyrochlores

Abstract

We present theoretical predictions for the electronic band and crystal structure of Bi1.5CdM1.5O7 (M = Nb, Ta) using DFT. The DFT calculated band gaps are in very good agreement with optical band gaps estimated from UV-Vis spectra.

Enhancement of dielectric and electric-field-induced polarization of bismuth fluoride nanoparticles within the layered structure of carbon nitride

“…Concentration driven structural distortion and phase transition behaviour is usually associated with a peak splitting and broadening effects. These phenomenon has been reported to study the ferroelectric and electromechanical properties of bismuth based dielectric material 32,33 . In the present system the transformation from cubic to pseudo-cubic/rhombohedral structural is mainly observed in the region of {111, 311, 222} diffraction peaks.…”

Synthesis and Characterization of a Novel Hydrated Layered Vanadium(III) Phosphate Phase K3V3(PO4)4·H2O: A Functional Cathode Material for Potassium-Ion Batteries

“…Our approach to crystal structure determination in this work is similar in philosophy to an earlier study on precise determination of the site occupancy, structure, and space group for bismuth-based pyrochlore photocatalysts. 25 In the pyrochlore series, substitution of a larger ion ( e.g ., Cd) can lead to changes in symmetry from cubic to rhombohedral with consequent implications for experimental and theoretical determinations of band gap values. 25 In this study, clarity on the structure and composition of the KVP phase influences our models on potassium transport in electrode materials for batteries.…”

“… 25 In the pyrochlore series, substitution of a larger ion ( e.g ., Cd) can lead to changes in symmetry from cubic to rhombohedral with consequent implications for experimental and theoretical determinations of band gap values. 25 In this study, clarity on the structure and composition of the KVP phase influences our models on potassium transport in electrode materials for batteries. We elaborate below on synthesis conditions for the optimum production of K 3 V 3 (PO 4 ) 4 ·H 2 O, key influences on ion transport, and spectroscopic interpretation of this important phase.…”

Lattice dynamics and high‐pressure properties of K‐ionic conducting system KNbTeO6

“…(and citations in there), the authors demonstrated that although the substituted pyrochlore structure for certain substitutions may appear cubic in XRD, it is likely already slightly distorted towards structures with reduced symmetry. [13] This work is a continuation of the systematic study of defect pyrochlore with the composition ABB 0 O 6 , where А-K + , Rb + , and Cs + ; B-Ta + , Nb 5+ , and Sb 5+ ; B 0 -Te 6+ and W 6+ . [14][15][16][17] We present results from Raman scattering studies at high pressures, on the ionic conducting system KNbTeO 6 (KNT), as well as results of lattice dynamics (LD) calculations for this compound.…”

“…For instance, in the work of Perenlei et al (and citations in there), the authors demonstrated that although the substituted pyrochlore structure for certain substitutions may appear cubic in XRD, it is likely already slightly distorted towards structures with reduced symmetry. [ 13 ]…”