Crystal growth and reinvestigation of the crystal structure of crednerite, CuMnO2

Abstract

Abstract Single crystals of nearly stoichiometric CuMnO2 were grown using a LiBO2 flux. They crystallize in the monoclinic space group C2/m with cell parameters a = 557.8(6) pm, b = 288.1(2) pm, c = 588.6(7) pm, β = 104.00(5)° and Z = 2. The structure can be described as a close packing of linear [O–Cu–O]3− groups parallel to the c-axis where MnIII-ions occupy edge sharing MnO6 octahedra forming layers perpendicular to the c-axis. It is closely related to that of delafossite, CuFeO2, but the Jahn-Teller effect of MnIII-ions breaks the three-fold symmetry.