Solid state diffraction

Dichalcogenolene complexes have been characterised by means of a large number of techniques. Nonetheless, solid-state diffraction techniques play a primary role, also in view of the importance of solid-state properties of metal... 

It is finally assumed that with all force constants and potential functions correctly specified in terms of the electronic configuration of the molecule, the nuclear arrangement that minimizes the steric strain corresponds to the observed structure of the isolated (gas phase) molecule. In practice however, the adjustable parameters, in virtually all cases, are chosen to reproduce molecular structures observed by solid-state diffraction methods. The parameters are therefore conditioned by the crystal environment and the minimized structure corresponds to neither gas phase nor isolated molecule [109],... 

The theory of chemical bonding is overwhelmed by a host of insurmountable obstacles the real orbitals and hybrids of LCAO have no physical, chemical or mathematically useful attributes - certainly not in the quantum-mechanical sense the distribution of electron density between atoms, in the form of spin pairs, is an overinterpretation of the empirical rules devised to catalogue chemical species the structures, assumed in order to generate free-molecule potential fields, are only known from solid-state diffraction experiments the assumption of directed bonds is a leap of faith, not even supported by crystal-structure analysis. The list is not complete. 

Another important point is the phase of the material. The ease of deterrnining structures of crystalline materials has changed the viewpoint of chemistry, so that often the structure and behavior of a compound examined in the solid state are thought also to be representative of the liquid, solution and gas phases. This is clearly not the case. There are always differences to be found between structures of the same material across the different phases. Crystalline phases are clearly the most relevant for typical applications in materials chemistry, but for chemical reactions of molecular compounds it is the solution phase that is most important. So we should not rely solely upon solid-state diffraction measurements to derive the structures of molecular compounds, but should also draw upon data available from chemical, spectroscopic, diffraction and other methods from other phases in order to get a better understanding of the structural form(s) of the molecule we are actually using. 

Neutron Diffraction, Instrumentation Photoelectron Spectrometers Proton Microprobe (Method and Background) Structure Refinement (Solid State Diffraction) X-ray Absorption Spectrometers... 

See also Inelastic Neutron Scattering, Applications Inelastic Neutron Scattering, Instrumentation Inorganic Compounds and Minerals Studied Using X-Ray Diffraction Materials Science Applications of X-Ray Diffraction Neutron Diffraction, Theory Powder X-Ray Diffraction, Applications Structure Refinement (Solid State Diffraction). 

See also Chiroptical Spectroscopy, General Theory Laboratory Information Management Systems (LIMS) Microwave Spectrometers Structure Refinement (Solid State Diffraction). 

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