Crystal Structures of the Perovskite‐Related System A/Rb/Cu(II)/Br (A=BA, Gu, PEA, 5‐AVA, H2en) with Winners, Losers and Compromises – Versatility from 0D to 3D on Different Levels

Abstract

AbstractBy precipitation from aqueous solutions in HBr we have synthesised new ternary compounds of the systems Rb/Cu(II)/Br and A/Cu(II)/Br with the organic cations A=BA, PEA, H2en, 5‐AVA. In addition, we have obtained several quaternary compounds A/Rb/CuBr2. All of the 11 new compounds represent the first Cu(II) bromides of the corresponding systems. The coordination of Cu2+ is dominated by corner‐sharing CuBr6 octahedra, which have four shorter (square‐planar) and two longer distances, due to the Jahn‐Teller effect. There are also representatives with CuBr4 tetrahedra. The dimensionality ranges from 3D (RbCuBr3), over 2D with single (BA2CuBr4, PEA2CuBr4, 5‐AVA2CuBr4, H2enCuBr4,) or double layers (Rb3Cu2Br7, 5‐AVA2RbCu2Br7), to 0D (Rb3CuBr5, Gu2CuBr4). A layer structure with edge‐sharing octahedra is found in GuCu2Br5. Unique structures are found for Rb7Cu3Br13, with a linear chain of elongated (4+2) and compressed (2+4) octahedra, and BACuBr3, with a chain of edge‐sharing tetrahedra. All compounds were characterised by single crystal XRD.