Accession Number : ADA186691

Title :   Cohesive Energies of Transition Metal Silicides and Phosphides.

Descriptive Note : Final technical rept. 2 Jul 82-30 Jun 87,

Corporate Author : STATE UNIV OF NEW YORK AT BINGHAMTON DEPT OF CHEMISTRY

Personal Author(s) : Myers, Clifford E

PDF Url : ADA186691

Report Date : 30 Sep 1987

Pagination or Media Count : 50

Abstract : Vaporization studies have been carried out by mass loss Knudsen effusion on the Ni-P and chromium-phosphorus systems and by Knudsen effusion mass spectrometry on the V-Si, Cr-Si and Ti-Si systems. The experimental data were used to calculate enthalpies of formation of the intermediate phases in these systems. The stabilities of the 1:1 compounds, expressed as enthalpies of atomization, have been compared with each other and with data on silicides, phosphides, and sulfides from the literature to assess factors for inclusion in a phenomenological model for stability. These factors include a) the number and type of bonding electrons, b) effective nuclear charges, c) valence state energies, d) the degree of partial electron transfer with a resulting Made lung energy, and e) contributions from Lewis acid-base interactions involving back-donation of electrons. Keywords: Transition metal silicides, Transition metal phosphides, Mass loss knudsen effusion, Knudsen effusion mass spectrometry, Vaporization behavior, Congruent vaporization, Thermodynamic activities, Phase equilibria, Free energy of formation, Enthalpy, Formation, Stability.

Descriptors :   *FREE ENERGY, *PHOSPHIDES, *SILICIDES, ACID BASE EQUILIBRIUM, ATOMIZATION, BEHAVIOR, BONDING, COHESION, EFFUSION, ELECTRON TRANSFER, ELECTRONS, ENERGY, ENTHALPY, EQUILIBRIUM(GENERAL), EXPERIMENTAL DATA, INTERACTIONS, KNUDSEN NUMBER, LOSSES, MASS, MASS SPECTROMETRY, METAL COMPOUNDS, PHASE, PHASE STUDIES, SULFIDES, THERMODYNAMICS, TRANSITION METALS, VALENCE, VAPORIZATION

Subject Categories : Inorganic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE