Crystallographic Studies and X-Ray Diffraction Patterns of Ba5R8Zn4O21 by Rietveld Refinements

Published

September 1, 2001

Author(s)

Winnie K. Wong-Ng, James A. Kaduk, J Dillingham

Abstract

The structure of the Ba₅R₈Zn₄O₂₁ series (R =lanthanides) was investigated using x-ray Rietveld refinements. The compounds were successfully prepared for R = Eu, Gd, Dy, Ho, Er, Tm, and Yb. For larger R, Ba₅R₈Zn₄O₂₁ was not stable, and tetragonal BaR₂ZnO₅ (La,Nd) and orthorhombic BaR₂ZnO₅ (Sm) phases were observed instead. Ba₅R₈Zn₄O₂₁ crystallizes in the tetragonal space group 14/m; for R=Yb to Eu, a ranges from 13.63502(5) to 13.96062(9) ³. The Zn²⁺ ions adopt a 5-fold distorted square pyramidal coordination. The 7-coordinate R³⁺ reside in monocapped trigonal prisms. These prisms share edges, and form layers stacked along the c-axis. There are two types of BaO polyhedra: bicapped square prisms (BaO₁₀), and irregular BaO₁₀ polyhedra.

Citation

Powder Diffraction

Volume

16

Issue

No. 3

Pub Type

Journals

Keywords

Ba₅R₈Zn₄O₂₁, crystallography, reference x-ray patterns, rietveld refinements

Citation

Wong-Ng, W. , A., J. and Dillingham, J. (2001), Crystallographic Studies and X-Ray Diffraction Patterns of Ba₅R₈Zn₄O₂₁ by Rietveld Refinements, Powder Diffraction (Accessed April 30, 2024)