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Updated: Jul 20, 2026

Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
Published on: May 10, 2021
KCaEr2CuS5: a new pentanary rare-earth layered chalcogenide without substitutional disorder
Hui-Yi Zeng1, Hansjürgen Mattausch, Arndt Simon
1State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China.
Abstract:
A new pentanary rare-earth chalcogenide without substitutional disorder, KCaEr2CuS5, was obtained from reaction of the Er-Ca-Cu-S precursor with KBr flux by either a two-step flux method or a direct reaction of the mixture of the binary components (1Cu2S:2Er2S3:3CaS) with excess KBr as flux. KCaEr2CuS5 crystallizes in the orthorhombic space group Cmcm (No. 63) with a = 3.9327(5) A, b = 13.410(2) A, c = 17.042(2) A, V = 898.8(3) A(3), Z = 4, R = 0.0632, and Rw = 0.0627. The KCaEr2CuS5 structure consists of four different building units: ErS6 octahedra, CaS6 octahedra, CuS4 tetrahedra, and KS6 trigonal prisms; it is characterized by [Er2CuS5]3- layers that are formed by the interconnection of double ErS6 octahedral chains with CuS4 tetrahedral chains in the a-c plane. K+ and Ca2+ cations are located in the cavities defined by S2- anions between the [Er2CuS5]3- layers. KCaEr2CuS5 is a semiconductor with an estimated band gap of 2.4 eV and shows a Curie-Weiss paramagnetic behavior in the 5-300 K range.
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