Structure and Magnetism of Novel Copper Molybdenum Oxides η-CuMoO4and β-Cu3Mo2O9

Abstract

Single crystals of the novel copper molybdenum oxides η-CuMoO4 and β-Cu3Mo2O9 are synthesized by a hydrothermal method. Both oxides have triclinic unit cells (space group \(P\bar{1}\)). The lattice constants of η-CuMoO4 are \(a = 6.352\) Å, \(b = 6.986\) Å, \(c = 7.447\) Å, α = 73.53 °, β = 72.98 °, and γ = 84.95 °; those of β-Cu3Mo2O9 are \(a = 7.391\) Å, \(b = 7.587\) Å, \(c = 7.971\) Å, α = 67.133 °, β = 89.67 °, and γ = 66.20 °. η-CuMoO4 contains the Cu4O16 cluster composed of four corner-shared CuO6 octahedra, while β-Cu3Mo2O9 contains the Cu6O16 cluster composed of six CuO4 squares. The magnetic susceptibility reveals that the magnetism of β-Cu3Mo2O9 reflects the cluster structure.