Crystal packing analysis

Mechanistic investigations of gas-solid and solid-solid reactions as well as their proper engineering require identifiable crystal surfaces for atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) [1,3, 13-15] in combination with X-ray diffraction data, which are the basis of crystal packing analyses [1,3,16-18]. 

A. Bruggink, Red. Trav. Chim. Pays Bas, 111, 111 (1992). Towards a Rational Design of Resolving Agents. Part IV. Crystal Packing Analyses and Molecular Mechanics Calculations for Five Pairs of Diastereomeric Salts of Ephedrine and a Cyclic Phosphoric Acid. 

NDI 5 is an eloquent example of the delicate balance between the intermolecular forces that determine crystal packing. Analysis of the X-ray structures of 5 crystallised from three different solvents - acetone, acetonitrile and benzene - reveals that the solid state arrangement of this L-phenylalanine methyl ester derivative of NDI is... 

The crystal packing analysis clearly shows, that there is nothing special with these examples. Anthracene 14 has a layered structure with a (100) cleavage plane... 

Dance 1 (2003) Distance criteria for crystal packing analysis of supramolecular motifs. New J Chem 27 22-27... 

The above shows that 20-50% of the crystal structures stored in the database do not lend themselves to automatic renormalization of hydrogen atom positions and to immediate and unchecked use in crystal packing analysis studies. True, the checks... 

The image of a single molecule, the structure of which has been determined by crystal structure analysis, shows a molecular structure, but not a crystal structure , an X-ray structure , or even worse an X-ray . The packing and the spatial arrangement of the molecules in a crystal are always an indispensable part of a crystal structure. 

An additional packing analysis of the crystal lattices demonstrates that also intermolecular distances C(H3)---(H3)C are sometimes rather small, for instance down to 361 pm in hexa-... 

A derived crystal packing model proved to be useful in resolving the crystal structure of a metastable polymorph of racemic modafinil, where details of the solved crystal structure of one polymorph was used as a basis for developing the structure of the other [12]. It was found that the calculated XRPD pattern matched well with the experimental data, indicating the correctness of the analysis. The powder diffraction of two polymorphs of chlorothalonil were solved to obtain... 

Plots of melting point against optical purity are commonly referred to as phase-composition diagrams. The direct proportionality of melting point with heat of fusion has also been employed to construct similar plots based on thermal analysis data. The classification of racemic modifications into three different types with regard to their crystal packing (32) can be made based on the overall shape of these plots as follows ... 

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