Crystallographic and Reference Pattern Determination of the Thermoelectric Oxyselenides (Bi1-xAxCuOSe) (A=Ba and Ca)

Published

August 3, 2017

Author(s)

Winnie K. Wong-Ng, Yonggao Yan, James A. Kaduk, Xinfeng Tang

Abstract

The crystal structures, solid solution limit, and powder X-ray reference diffraction patterns for two ‘natural superlattice’ series Bi1-xBaxCuOSe (x = 0.05, 0.075, 0.1, 0.2, and 0.3), and Bi1-xCaxCuOSe (x=0, 0.05, 0.075, 0.1, 0.2 and 0.3) have been determined. The structure/property relationships of these thermoelectric materials are summarized. As the ionic radius of Ba2+ is greater than that of Bi3+, the unit cell volume, V, of Bi1-xBaxCuOSe increases progressively from x=0 to x=0.2 (from 137.868(5) Å3 to 141.194(10) Å3, respectively). However, even though the ionic radius of Ca2+ is smaller than that of Bi3+, the unit cell volumes, V, of Bi1-xCaxCuOSe also show an increasing trend as a function of x (137.868(5) Å3 to 139.295(12) Å3 from x=0 to 0.3, respectively) due to the relatively large increase in c parameter. The structure of Bi1-xAxCuOSe (A=Ba and Ca) can be considered as built from [Bi2(1-x)A2xO2]2(1-x)+ layers normal to the c-axis alternating with fluorite-like [Cu2Se2]2(1-x]- layers in the c-direction. The substitutions of Ba and Ca on the Bi site of Bi1-xAxCuOSe lead to the weakening of the ‘bonding’ between the [Bi2(1-x)A2xO2]2(1-x)+ and the [Cu2Se2]2(1-x]- layers (a decrease of Columbic force), resulting in an increase of the c-axis parameter and V. Powder X-ray diffraction patterns of Bi1-xAxCuOSe were submitted for inclusion in the Powder Diffraction File (PDF).

Citation

Crystals

Volume

72

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.solidstatesciences.2017.08.006

Keywords

thermoelectric material, Bi1-xBaxCuOSe, Bi1-xCaxCuOSe, powder X-ray reference patterns, structure/property relationships.

Citation

Wong-Ng, W. , Yan, Y. , Kaduk, J. and Tang, X. (2017), Crystallographic and Reference Pattern Determination of the Thermoelectric Oxyselenides (Bi1-xAxCuOSe) (A=Ba and Ca), Crystals, [online], https://doi.org/10.1016/j.solidstatesciences.2017.08.006 (Accessed December 15, 2024)