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Author Wiedemeier, Heribert
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CADMIUM COMPOUNDS ♦ CHALCOGENIDES ♦ ENTHALPY ♦ FREE ENTHALPY ♦ HALIDES ♦ IONIZATION ♦ MAGNESIUM COMPOUNDS ♦ MERCURY COMPOUNDS ♦ POTASSIUM COMPOUNDS ♦ SODIUM COMPOUNDS ♦ STRONTIUM COMPOUNDS ♦ VACANCIES ♦ ZINC COMPOUNDS ♦ ALKALI METAL COMPOUNDS ♦ ALKALINE EARTH METAL COMPOUNDS ♦ CRYSTAL DEFECTS ♦ CRYSTAL STRUCTURE ♦ ENERGY ♦ HALOGEN COMPOUNDS ♦ PHYSICAL PROPERTIES ♦ POINT DEFECTS ♦ THERMODYNAMIC PROPERTIES
Abstract Correlations of computed Schottky constants (K{sub S}=[V''{sub Zn}][V{sub S}{sup ..}]) with structural and thermodynamic properties showed linear dependences of log K{sub S} on the lattice energies for the Zn-, Cd-, Hg-, Mg-, and Sr-chalcogenides and for the Na- and K-halides. These findings suggest a basic relation between the Schottky constants and the lattice energies for these families of compounds from different parts of the Periodic Table, namely, {Delta}H{sub T,L}{sup o}=-(2.303nRT log K{sub S})+2.303nRm{sub b}+2.303nRTi{sub b}. {Delta}H{sub T,L}{sup o} is the experimental (Born-Haber) lattice energy (enthalpy), n is a constant approximately equal to the formal valence (charge) of the material, m{sub b} and i{sub b} are the slope and intercept, respectively, of the intercept b (of the log K{sub S} versus {Delta}H{sub L}{sup o} linear relation) versus the reciprocal temperature. The results of this work also provide an empirical correlation between the Gibbs free energy of vacancy formation and the lattice energy. - Graphical abstract: For the Zn-chalcogenides, the quantities n and I{sub e} are 2.007 and 650.3 kcal (2722 kJ), respectively. For the other groups of compounds, they are approximately equal to the formal valences and ionization energies of the metals: Log K{sub S{approx}}-(2.303nRT){sup -1} (0.99{Delta}H{sup o}{sub T,L}-I{sub e}).
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2010-10-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 183
Issue Number 10


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