Crystal growth at high pressure and the problem of characterization of theinterstitial phases in the B-C-O system

Different crystal growth methods were used to obtain single crystals of int erstitial phases based on the alpha -boron structure in the B-O and B-C-O s ystems at pressures of 3-7 GPa. and temperatures of 1500-2000 K. Boron subo xide carbide B(C,O)(0.16) crystals with sizes up to 250 mum, suitable for c omplete structure analysis, were prepared by chemical reaction between B4C and B2O3 (molar ratio 1:1). The hexagonal unit cell parameters of the B(C,O )(0.16) compound are: a = 5.618(1) Angstrom, c = 12.122(1) Angstrom, c/a = 2.158, Z = 38.54 and space group R (3) over barm. The analytical method for estimation of the chemical composition and the number of atoms per unit ce ll is presented for this kind of compound. (C) 2001 Elsevier Science B.V. A ll rights reserved.