Gastone Gilli and Paola Gilli
- Published in print:
- 2009
- Published Online:
- September 2009
- ISBN:
- 9780199558964
- eISBN:
- 9780191720949
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199558964.003.0004
- Subject:
- Physics, Crystallography: Physics
Crystallographic databases collect some 300,000 structures, tens of thousands including one or more H-bonds. This impressive archive take in all varieties of inter- and intra-molecular H-bonds of any ...
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Crystallographic databases collect some 300,000 structures, tens of thousands including one or more H-bonds. This impressive archive take in all varieties of inter- and intra-molecular H-bonds of any strength made by all possible atoms and can be asked any question on the H-bond nature provided we know how to do it. This chapter selects appropriate methods (crystal-structure correlations, Pauling's bond number, bond-number conservation, and Lippincott and Schroeder's method) and applies them to large sets of structural data representative of the most important H-bond classes. Particular attention is paid to strong O-H···O, N-H···N, and N-H···O/O-H···N resonance-assisted H-bonds (RAHBs) and their interpretation by different theoretical models. Three other classes of strong charge-assisted H-bonds (CAHBs) are identified and the H-bond classification is completed in six classes (the chemical leitmotifs). Results are interpreted in terms of electrostatic-covalent H-bond model (ECHBM) and PA/pKa equalization principle. A general equation linking H-bond energies and geometries is attempted.Less
Crystallographic databases collect some 300,000 structures, tens of thousands including one or more H-bonds. This impressive archive take in all varieties of inter- and intra-molecular H-bonds of any strength made by all possible atoms and can be asked any question on the H-bond nature provided we know how to do it. This chapter selects appropriate methods (crystal-structure correlations, Pauling's bond number, bond-number conservation, and Lippincott and Schroeder's method) and applies them to large sets of structural data representative of the most important H-bond classes. Particular attention is paid to strong O-H···O, N-H···N, and N-H···O/O-H···N resonance-assisted H-bonds (RAHBs) and their interpretation by different theoretical models. Three other classes of strong charge-assisted H-bonds (CAHBs) are identified and the H-bond classification is completed in six classes (the chemical leitmotifs). Results are interpreted in terms of electrostatic-covalent H-bond model (ECHBM) and PA/pKa equalization principle. A general equation linking H-bond energies and geometries is attempted.
ANGELO GAVEZZOTTI
- Published in print:
- 2006
- Published Online:
- January 2010
- ISBN:
- 9780198570806
- eISBN:
- 9780191718779
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198570806.003.0008
- Subject:
- Physics, Atomic, Laser, and Optical Physics
Structure correlation studies were first carried out on intramolecular parameters, a classic work of which involved molecular deformations at a carbonyl center as a function of the intermolecular ...
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Structure correlation studies were first carried out on intramolecular parameters, a classic work of which involved molecular deformations at a carbonyl center as a function of the intermolecular distance to an incoming nucleophile. In further applications, the term ‘structure correlation’ was extended to include all studies in which molecular or crystal properties are analysed in a systematic way over the database, to reveal correlations between structural or energetic properties of crystallised molecules. This chapter discusses correlation studies in organic solids, the Cambridge Structural Database (CSD) of organic crystals, structure correlation, retrieval of crystal and molecular structures from the CSD, the SubHeat database, geometrical categorisation of intermolecular bonding, space analysis of molecular packing modes, empty space versus filled space, close packing in crystals, calculation of intermolecular energies in crystals, basic concepts on lattice energies, sublimation entropies and vapor pressures of crystals, general-purpose force fields for organic crystals, correlation between molecular and crystal properties, and acceptable crystal structures.Less
Structure correlation studies were first carried out on intramolecular parameters, a classic work of which involved molecular deformations at a carbonyl center as a function of the intermolecular distance to an incoming nucleophile. In further applications, the term ‘structure correlation’ was extended to include all studies in which molecular or crystal properties are analysed in a systematic way over the database, to reveal correlations between structural or energetic properties of crystallised molecules. This chapter discusses correlation studies in organic solids, the Cambridge Structural Database (CSD) of organic crystals, structure correlation, retrieval of crystal and molecular structures from the CSD, the SubHeat database, geometrical categorisation of intermolecular bonding, space analysis of molecular packing modes, empty space versus filled space, close packing in crystals, calculation of intermolecular energies in crystals, basic concepts on lattice energies, sublimation entropies and vapor pressures of crystals, general-purpose force fields for organic crystals, correlation between molecular and crystal properties, and acceptable crystal structures.
Sergry V. Krivovichev
- Published in print:
- 2009
- Published Online:
- May 2009
- ISBN:
- 9780199213207
- eISBN:
- 9780191707117
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213207.003.0006
- Subject:
- Physics, Crystallography: Physics
This chapter analyses ‘structure-composition’ correlations in inorganic oxysalts by means of dimensional reduction. It is shown that the dimensionality of structural units in inorganic oxysalts is ...
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This chapter analyses ‘structure-composition’ correlations in inorganic oxysalts by means of dimensional reduction. It is shown that the dimensionality of structural units in inorganic oxysalts is controlled by the incorporation of ionic component (e.g., alkali metal salt or oxide) into parent structure. This allows for compositional diagrams with fields of units of different dimensionality or different connectedness values of polyhedra. For hydrated oxysalts, it is shown that incorporation of water and acid also reduces dimensionality.Less
This chapter analyses ‘structure-composition’ correlations in inorganic oxysalts by means of dimensional reduction. It is shown that the dimensionality of structural units in inorganic oxysalts is controlled by the incorporation of ionic component (e.g., alkali metal salt or oxide) into parent structure. This allows for compositional diagrams with fields of units of different dimensionality or different connectedness values of polyhedra. For hydrated oxysalts, it is shown that incorporation of water and acid also reduces dimensionality.