Buckle-Layered, Decorated Square-Kagome System KCu 7 BiO 4 (SO 4 ) 5

作者：Larisa Shvanskaya, T. D. Bushneva, Д. А. Чареев, Leonid S. Taran, В. В. Мазуренко, S. V. Streltsov, A. N. Vasiliev · 发表于：Inorganic Chemistry · 年份：2025 · DOI：10.1021/acs.inorgchem.5c04285 · 被引用次数：1 · 研究领域：Advanced Condensed Matter Physics、Physics of Superconductivity and Magnetism、Topological Materials and Phenomena

We report the gas-transport synthesis, crystal structure, and magnetic properties of the buckle-layered KCu 7 BiO 4 (SO 4 ) 5, which enriches few in number the family of decorated square-kagome systems consisting of the rare mineral nabokoite KCu 7 TeO 4 (SO 4 ) 5 Cl and synthetic Na 6 Cu 7 BiO 4 (PO 4 ) 4 (Cl,OH) 3 . The title compound crystallizes in the tetragonal space group P 4/ ncc with unit cell parameters a = 9.7731(1) and c = 20.4094(6) Å, Z = 4, and differs from nabokoite-like phases in the arrangement of Cu-centered polyhedra within the square-kagome-like layer, as well as in their connection with decorating ions. Although the square-kagome motif is clearly visible in the crystal structure of KCu 7 BiO 4 (SO 4 ) 5, from the magnetic perspective, it is a much more complex network. It evidences no indications on the formation of the short-range order, but KCu 7 BiO 4 (SO 4 ) 5 experiences a long-range order at Neel temperature T N = 12 K. In comparison with negative Weiss temperature Θ = −219 K, it gives the frustration ratio F = |Θ|/ T N ≥ 18. This very large value points to both fierce competition of antiferromagnetic exchange interactions and the low dimensionality of the magnetic subsystem. Density functional theory calculations identify pathways of leading exchange interactions between Cu 2+ ions in both buckled layers and between them.