Structure and preparation of boron-rich borides

Journal Article · Tue Apr 15 00:00:00 EST 1986 · AIP Conf. Proc.; (United States)

DOI:https://doi.org/10.1063/1.35595· OSTI ID:5541551

Higashi, I

The B/sub 12/ icosahedral compounds may be classified into 8 types: 1. ..cap alpha..-rhombohedral boron type; 2. ..beta..-rhombohedral boron type; 3. ..cap alpha..-tetragonal boron type; 4. ..beta..-tetragonal boron type; 5. AlB/sub 10/ (or AlC/sub 4/B/sub 26/) type; 6. NaB/sub 15/ type; 7. YB/sub 66/ type; and 8. ..gamma..-AlB/sub 12/ type. Both ..cap alpha..-AlB/sub 12/ and ..gamma..-AlB/sub 12/ consist of B/sub 12/ icosahedra and B/sub 20/ units, and have a B/sub 12/ icosahedral framework analogous to that in ..beta..-rhombohedral boron. Charge balance among the boron polyhedral units in these phases was investigated by counting the number of contacts between the metal atoms and the boron units. Precision X-ray diffraction studies on B/sub 13/ C/sub 2/, ..cap alpha..-AlB/sub 12/ and LiAlB/sub 14/ revealed the difference electron densities, demonstrating three-center and two-center bonds in the B/sub 12/ icosahedral structures. A net charge of (B/sub 12/)/sup 1.2-/ was observed for LiAlB/sub 14/. The single crystal growth of some B/sub 12/ icosahedral borides from metal solution is discussed.

• Research Organization: The Institute of Physical and Chemical Research, Wako-shi, Saitama, 351-01 Japan
• OSTI ID: 5541551
• Report Number(s): CONF-850786-
• Journal Information: AIP Conf. Proc.; (United States), Vol. 140:1; Conference: International conference on the physics and chemistry of boron and boron-rich borides, Albuquerque, NM, USA, 29 Jul 1985
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORIDES
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
CHARGE DISTRIBUTION
CRYSTAL GROWTH
ELECTRON DENSITY
METALS
MONOCRYSTALS
ORTHORHOMBIC LATTICES
SOLUTIONS
TETRAGONAL LATTICES
X-RAY DIFFRACTION
BORON COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTALS
DIFFRACTION
DISPERSIONS
ELEMENTS
MIXTURES
SCATTERING
SYNTHESIS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication