Synthesis, crystal structure and properties of [Sr2Cu(C2O4)3(H2O)7]: precursor of Sr2CuO3 oxide

Abstract

[Sr₂Cu(C₂O₄)₃(H₂O)₇](C₂O₄^2–= oxalate ion) has been synthesized and characterized. The structure has been determined by X-ray diffraction methods. It crystallizes in the triclinic system, space group Pī with a= 6.349(2)Å, b= 10.258(2)Å, c= 15.737(2)Å, α= 73.21(1)°, β= 93.66(2)°, γ= 76.44(2)°, V= 944.3(4)ų, Z= 2. The structure consists of an intricate network of Sr²⁺ and Cu²⁺ ions linked by oxalate and H₂O groups. A nonacoordinated arrangement around the two strontium ions and a distorted octahedral geometry for the copper(II) ions are observed. The thermal decomposition of this complex yields a unique and homogeneous phase at comparatively short reaction times and lower temperatures than the ceramic method. Conductivity measurements of the oxide obtained show semiconductor behaviour.