Chemical bonding in refractory transition metal compounds with 8, 9, and 10 valence electrons

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(87)90056-9· OSTI ID:5926596

Blaha, P; Schwarz, K; Kubel, F; Yvon, K

The chemical bonding in the refractory transition metal compounds TiC, TiN, and VN is investigated by experimental and theoretical techniques. High-precision x-ray diffraction is used to determine the electron densities in these three compounds experimentally. The x-ray structure factors and the respective valence electron densities are used twice, once to understand the chemical bonding and once to relate the experimental charge densities to those obtained from band structure calculations. These calculations, which in general are in very good agreement with experimental data, utilize the linearized augmented plane wave (LAPW) method. Theory and experiment lead to a detailed analysis of the chemical bonding in these compounds with 8, 9, and 10 valence electrons. By decomposition of the theoretical charge density into contributions from different states (energy regions), it was possible to show the strong covalent nonmetal p-metal d interaction, which is otherwise apparent only in TiC, but not in TiN or VN. In the latter two compounds the additional electrons occupy mainly metal d states with t/sub 2g/ symmetry, so that in the total valence charge densities the most important bonding feature is covered. In addition to covalent interactions all compounds have a metallic bonding contribution as well as a considerable charge transfer from the metal to the nonmetal site. This mixture in chemical bonding accounts for the unusual combination of properties such as ultrahardness, high melting points, and good conductivity.

• Research Organization: Institut fuer Technische Elektrochemie, Vienna, Austria
• OSTI ID: 5926596
• Journal Information: J. Solid State Chem.; (United States), Vol. 70:2
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
TITANIUM CARBIDES
CHEMICAL BONDS
ELECTRON DENSITY
TITANIUM NITRIDES
VANADIUM NITRIDES
BAND THEORY
BINDING ENERGY
ELECTRIC CONDUCTIVITY
EXPERIMENTAL DATA
MELTING POINTS
X-RAY DIFFRACTION
CARBIDES
CARBON COMPOUNDS
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTRICAL PROPERTIES
ENERGY
INFORMATION
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
PHYSICAL PROPERTIES
PNICTIDES
SCATTERING
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VANADIUM COMPOUNDS
400201* - Chemical & Physicochemical Properties
360204 - Ceramics
Cermets
& Refractories- Physical Properties