THE CRYSTAL-STRUCTURE OF CU(2)M(BO3)O-2 ( M=FE3+, GA3+)

Single Crystals of the compounds Cu(2)M(BO3)O-2 (M = Fe3+(I), Ga3+(II) ) were obtained by a B2O3 flux-technique. They crystallize in a monocl inic distorted variant of a Ludwigite structure with a partly ordered metal distribution. X-ray investigations on single crystals led to the space group C-2h(5)-P2(1)/c (No.14); I: a = 3.108(1); b = 12.003(1); c = 9.459(3) Angstrom; P = 96.66(3)degrees; Z = 4 and II: a = 3.1146(2 ); b = 11.921(3); c = 9.477(2) Angstrom; beta = 97.91(2)degrees; Z = 4 . All metal-sites are distorted octahedraly coordinated by oxygen-ions . The structure contains isolated planar BO3-units and oxygen which is not coordinated to boron.