Related Experiment Video
Updated: Jun 13, 2026

Picometer-Precision Atomic Position Tracking through Electron Microscopy
Published on: July 3, 2021
Al14Ba8La(26.3)Ru18Sr(53.7)O167: a variant of cubic perovskite with isolated RuO6 units
F J Zúñiga1, F J García-García, M Hoelzel
1Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apartado 664, 48080 Bilbao, Spain. javier.zuniga@ehu.es
Abstract:
The crystal structure of the title aluminium barium lanthanum ruthenium strontium oxide has been solved and refined using neutron powder diffraction to establish the parameters of the oxygen sublattice and then single-crystal X-ray diffraction data for the final refinement. The structure is a cubic modification of the perovskite ABO(3) structure type. The refined composition is Ba(0.167)La(0.548)Sr(1.118)Ru(0.377)Al(0.290)O(3.480), and with respect to the basic perovskite structure type it might be written as (Ba(8)La(13.68)Sr(34.32))(Al(13.92)La(12.64)Ru(18.08)Sr(19.36))O(192-x), with x = 24.96. The metal atoms lie on special positions. The A-type sites are occupied by Ba, La and Sr. The Ba atoms are located in a regular cuboctahedral environment, whereas the La and Sr atoms share the same positions with an irregular coordination of O atoms. The B-type sites are divided between two different Wyckoff positions occupied by Ru/Al and La/Sr. Only Al and Ru occupy sites close to the ideal perovskite positions, while La and Sr move away from these positions toward the (111) planes with high Al content. The structure contains isolated RuO(6) octahedra, which form tetrahedral substructural units.
Related Concept Videos
Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Imperfections in Crystal Structure: Non-Stoichiometric Defects
Imperfections in Crystal Structure: Stoichiometric Point Defects
Lattice Centering and Coordination Number
Types of Unit Cells
Imagine taking a large number of identical...
Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...

