CRYSTAL STRUCTURE OF A COBALT OXIDE LuBaCo4O7

Crystals of LuBaCo4O7+δ (114Lu) have been obtained by spontaneous crystallization of slowly cooled nonstoichiometric melt of the system Lu-Ba-Co-O. The crystals have been characterized by EDX microprobe and synchrotron radiation powder diffraction. Structure refinement has been carried out (automated diffractometer Bruker X8 APEX with a CCD detector, MoKα, graphite monochromator, ϑmax = 32.54°). Parameters of the hexagonal unit cell: space group P63mc, a = 6.2601(1) A c = 10.2017(3) A V = 346.23(1) A3, Z = 2, dcalc = 6.331 g/cm3. Framework structure of the wurtzite type has been refined anisotropically to R-factor 0.0174. Charge balance in the compound and geometrical matching of structural fragments are discussed.