Structure of icosahedral borides by Raman spectroscopy

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5844867

Tallant, D R; Aselage, T L; Emin, D

We have obtained Raman spectra of icosahedral boron-rich solids. The spectra of {alpha}-rhombohedral boron, boron arsenides, and boron phosphide are consistent with highly-ordered materials. Polarization studies have resulted in symmetry assignments for most of the Raman bands of {alpha}-rhombohedral boron. In contrast, the Raman spectra of the boron carbides reveal local substitutional disorder. They also change progressively as a function of carbon content. A structural model for the boron carbides has been developed to explain the Raman and infrared absorption spectra, x-ray data, and electrical and thermal transport properties. Raman spectra of boron carbide samples enriched in {sup 10}B, {sup 11}B, and {sup 13}C reveal details of the atomic motions. The vibrational frequencies and exceptionally narrow linewidths of certain Raman modes are discussed in terms of a strong'' bond model. In this model certain vibrational modes involving relatively stiff bonds between chain atoms, chain and icosahedral atoms, and atoms on different icosahedral are decoupled from the boride lattice by weak, intraicosahedral bonds. 15 refs., 8 figs., 1 tab.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5844867
• Report Number(s): SAND-91-0236C; CONF-910885-1; ON: DE91010872
• Resource Relation: Conference: 10. international symposium on boron, borides and related compounds, Albuquerque, NM (USA), 27-30 Aug 1991
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON CARBIDES
OSCILLATION MODES
RAMAN SPECTRA
BORON 10
BORON 11
BORON ARSENIDES
CARBON 13
ELECTRICAL PROPERTIES
INFRARED SPECTRA
POLYCRYSTALS
SPIN ORIENTATION
STRUCTURAL MODELS
SYMMETRY
VIBRATIONAL STATES
X-RAY SPECTRA
ARSENIC COMPOUNDS
ARSENIDES
BORON COMPOUNDS
BORON ISOTOPES
CARBIDES
CARBON COMPOUNDS
CARBON ISOTOPES
CRYSTALS
ENERGY LEVELS
EVEN-ODD NUCLEI
EXCITED STATES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORIENTATION
PHYSICAL PROPERTIES
PNICTIDES
SPECTRA
STABLE ISOTOPES
360204* - Ceramics
Cermets
& Refractories- Physical Properties
360603 - Materials- Properties