Structure and preparation of boron-rich borides

Journal Article · Tue Apr 15 04:00:00 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), Journal Name: AIP Conf. Proc.; (United States) Vol. 140:1; ISSN APCPC
• Country of Publication: United States
• Language: English

Related Subjects

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