PREPARATION AND CRYSTAL-STRUCTURE OF BALI[BO3]

For the first time colourless lamellar single crystals of BaLi[BO3] ha ve been prepared from intimate mixtures of BaO2, Li2O and B2O3. The st ructure determination from four-circle diffractometer data (MoKalphaBA R, 882 independent reflections, R = 2.4%, R(w) = 1.9%) confirms the sp ace group P2(1)/c with Z = 4; a = 646.1(3), b = 710.7(2), c = 740.3(3) pm, beta = 117.99(3)-degrees. Characteristic units of the structure a re layers infinity2{Li[BO3]} parallel to (100) consisting of trigonal planar [BO3] groups and distorted [LiO5] pyramids. Effective Coordinat ion Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Par t of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are c alculated and discussed.