Crystal structure of tetragonal (CeB2C2)-B-11

Neutron powder diffraction experiments were performed in order to determine the crystal structure of (CeB)-B-11 C-2(2), since the structure of CeB2C2 has been examined only by X-ray techniques and the positions of the B and C atoms in this compound are suspicious. The neutron diffraction pattern rev eals that the crystal structure of (CeB)-B-11 C-2(2) has a symmetry with th e space group of P4/mbm, where the Ce atoms occupy the 2(a) sites (0,0,0) a nd the B and C atoms 4(h) sites (x,x + 0.5,0.5) with positional parameters of X-B = 0.361(1) and x(C) = 0.160(1) at 15.0 K. (C) 1999 Elsevier Science Ltd. All rights reserved.