Related Experiment Video
Updated: Jun 20, 2026

High Pressure Single Crystal Diffraction at PX^2
Published on: January 16, 2017
Eu3Si(15-x)Al(1 + x)OxN(23-x) (x approximately 5/3) as a commensurate composite crystal
Yuichi Michiue1, Kousuke Shioi, Naoto Hirosaki
1National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. michiue.yuichi@nims.go.jp
Abstract:
A new Eu-SiAlON crystal, Eu3Si(15-x)Al(1 + x)O(x)N(23-x) (x approximately 5/3), was found and the structure was determined by an X-ray diffraction technique using a twinned sample. The structure consists of a host framework, which is constructed by the connection of MX4 tetrahedra (M: Si or Al; X: O or N), and Eu ions as the guest ions. The structure is considered to be a commensurate composite crystal. The basic vectors are a1 = a/3, b and c for the first substructure, and a2 = a/5, b and c for the second substructure. The first substructure consists of part of the host framework and the Eu ions, while the remainder of the host structure is taken as the second substructure. Possible phases belonging to the series are proposed using the composite crystal model in (3 + 1)-dimensional superspace. Chemical composition, possible space groups, cell parameters, and the basic model for those phases are presented.
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...
Symmetry Elements in a Crystal
Unit Cells
Law of Rational Indices
Lattice Energies of Ionic Crystals
Determination of Crystal Structures

