Thermodynamics and electrons

ALTHOUGH MORE THAN ONE DEFECT REACTION MAY BE APPLICABLE TO A GIVEN SITUATION, ONLY ONE IS USUALLY FAVORED BY THE PREVAILING THERMODYNAMIC AND ELECTRON-COMPENSATION CONDITIONS. 

Gonzalez-Calbet, J.M. Alario-Franco, M.A. (1982) A thermodynamic and electron microscopic study of the decomposition of akaga-neite. Thermochim. Acta 58 45-51 Gonzalez-Calbet, J.M., Alario-Franco, M.A. Gayoso-Andrade, M. (1981) The porous structure of synthetic akaganeite. J. inorg. nucl. Chem. 43 257-264... 

Log P and MR are considered thermodynamic descriptors, pR a combined thermodynamic and electronic index, and a an electronic property index, E is designed to account for steric effects. Corrections for non-additivity, based upon the chemical bonding topology, have been suggested and used. These include proximity, bond type, ring, and group shape correction features. (8-10)... 

Forster cycle Indirect method of determination of excited state equilibria, such as pK values, based on ground state thermodynamics and electronic transition energies. This cycle considers only the difference in molar enthalpy change (AAH) of reaction of ground and excited states, neglecting the difference in molar entropy change of reaction of those states (AAS). 

All thermodynamic and electronic properties of molecules are closely linked to the quantum potential. Many of these, for instance electronegativity, only known from empirical relationships before, can now be demonstrated to be of fundamental theoretical importance. The close similarity between chemical potential of a system and the quantum potential of component molecules establishes a direct link between quantum mechanics and thermodynamics, without statistical considerations. This relationship has direct bearing on the nature, mechanism and kinetics of chemical bond formation, including sterically improbable intramolecular rearrangements. 

We will first describe the common structures of crystals and then give the molecular orbital explanation of their bonding. Finally, we will describe some of the thermodynamic and electronic properties of these materials and their uses. 

Actinide elements (Z = 89 - 103) include the heaviest natural and most of the synthetic transuranium elements. They form a series of transition elements, characterized by the filling of an inner - the 5f-electron shell. The elements from Ac (Z = 89) to Es (Z = 99) are available in quantities sufficient for solid state studies. Elemental actinides are metallic. The methods of metal preparation and characterization have been improved to yield samples of known purity and crystal structure, sometimes in the form of single crystals. Recent measurements of structural, thermodynamic and electronic properties have emphasized elements in the beginning and in the centre of the actinide series. 

Aromaiiciiy as a special propeity of molecules like benzene is covered in (his section. Structural, thermodynamic, and electronic considerations are presented and serve as an introduction to the more general di.scussion that is presented in Section 15-7. For now, note simply that the aromaticity of benzene is renccied in (1) its symmetrical structure (as a resonance hybrid), (2) its unexpectedly enhanced thermodynamic stability, and (3) its unusual electronic structure with a completely filled. set of strongly stabilized bonding molecular orbitals. 

Cluster condensation begins with two clusters sharing one or more atoms. At present, oligomers with endohedral transition metal atoms are only known with octahedral clusters, TRs. Obviously, T atoms are too big to be accommodated in tetrahedra or trigonal bipyramids. On the other hand, oligomers always compete both thermodynamically and electronically with chains the more cluster atoms are shared, the lesser the electron cotuit has to be, scaled to one endohedral atom. 

A discussion of the surface tension, y, of the liquid R s must involve a discussion of mechanical, thermodynamic, and electronic properties. Nonetheless, we include it at this point in our review. 

Radialenes have been and are still objects of study for a variety of reasons. Their particular structures, the high chemical reactivity of the parent systems, and the quest for derivatives with specific functionalization have spurred the interest of synthetically oriented chemists. Molecular properties such as structure, bonding, thermodynamics, and electronic properties have attracted... 

Measurements in the gas phase offer several advantages, among them the direct comparison to quantum-chemical calculation and the broad availability of thermodynamic and electronic parameters for the gas phase. However, data on the gas phase reactivity of n,7i -excited ketones are rare [172,233-239]. This is mainly caused by experimental difficulties since most ketones such as benzophenone are not sufficiently volatile and therefore require elevated temperatures to be studied experimentally, which limits the comparison with the ubiquitous solution measurements at room temperature [236,237]. In contrast, a comprehensive data set on the gas-phase photoreactivity of azoalkanes has recently become available [65], motivated by the observation of Steel and cowoikers that the fluorescence of DBO can be easily monitored in the gas phase [33]. 

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