Structure of icosahedral borides by Raman spectroscopy

Conference · Mon Jul 01 04:00:00 EDT 1991 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.40841· OSTI ID:5844867

Tallant, D. R. ^[1]; Aselage, T. L. ^[1]; Emin, D. ^[1]

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1. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

We have obtained Raman spectra of icosahedral boron-rich solids. The spectra of α-rhombohedral boron, boron arsenide, and boron phosphide are consistent with highly-ordered materials. Polarization studies have resulted in symmetry assignments for most of the Raman bands of α-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 ¹⁰B, ¹¹B, and ¹³C 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 icosahedra are decoupled from the boride lattice by weak, intraicosahedral bonds.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5844867
• Report Number(s): SAND--91-0236C; CONF-910885--1; ON: DE91010872
• Conference Information: Journal Name: AIP Conference Proceedings Journal Volume: 231
• Country of Publication: United States
• Language: English

Related Subjects

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