Crystal structures of CCa2CuO5 and CSr1.9Ca1.1Cu2O7 refined from single crystal data

Single crystals were grown for new layered oxycarbonates CCa2CuO5 and CSr1.9Ca1.1Cu2O7 at 6 GPa using a belt-type apparatus. Their crystal structures were determined using single crystal X-ray diffraction data with R1(wR2) = 0.0294(0.0659) and 0.0199(0.0457) for CCa2CuO5 and CSr1.9Ca1.1Cu2O7, respectively. These phases crystallize in the space group P4/mmm (No. 123), Z = 1 with a = 3.8157(1) Angstrom, c = 7.1426(3) Angstrom for CCa2CuO5 and a = 3.8753(1) Angstrom, c = 10.6765(5) Angstrom for CSr1.9Ca1.1Cu2O7. In contrast to CSr2CuO5, no ordering in the orientation of the triangular CO3 groups was revealed in CCa2CuO5 and CSr1.9Ca1.1Cu2O7. (C) 2002 Elsevier Science B.V. All rights reserved.