New quaternary carbon and nitrogen stabilized polyborides: REB 15.5CN ( RE: Sc, Y, Ho, Er, Tm, Lu), crystal structure and compound formation
Abstract
A new family of quaternary carbon and nitrogen containing Rare Earth ( RE: Sc, Y, Ho, Er, Tm and Lu) borides: REB 15.5CN, has been synthesized and structurally characterized by powder X-ray diffraction data. They are all isotypic with Sc 1- xB 15.5CN whose structure was solved based on single-crystal X-ray data and HRTEM investigations. The structure refinement converged at a R( F2) value of 0.044 for 364 reflections. The new structure type of Sc 1- xB 15.5CN is composed of a three-dimensional network based on interconnected slabs of boron (B 12) ico icosahedra and (B 6) oct octahedra. A linear [CBC] chain and nitrogen tightly bridges icosahedra. Sc partially occupies voids in the sheets of boron octahedra. It crystallizes with the trigonal space group P3m1, with Z=2. Lattice parameters (nm) are as follows: for RE: Sc, a, b=0.5568(4), c=1.0756(2); Y, a, b=0.55919(6), c=1.0873(2); Ho, a, b=0.55883(7), c=1.0878(6); Er, a, b=0.55889(5), c=1.0880(6); Tm, a, b=0.5580(1), c=1.0850(6); Lu, a, b=0.55771(9), c=1.0839(4). Magnetic characterization of ErB 17C 1.3N 0.6 has been performed.
- Publication:
-
Journal of Solid State Chemistry France
- Pub Date:
- February 2004
- DOI:
- 10.1016/j.jssc.2003.02.003
- Bibcode:
- 2004JSSCh.177..431L