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In chemistry, the Sabatier principle is a qualitative concept in heterogeneous catalysis named after the French chemist Paul Sabatier. It states that the interactions between the catalyst and the reactants should be "just right"; that is, neither too strong nor too weak. If the interaction is too weak, the molecule will fail to bind to the ...
One of Pauling's examples is olivine, M 2 SiO 4, where M is a mixture of Mg 2+ at some sites and Fe 2+ at others. The structure contains distinct SiO 4 tetrahedra which do not share any oxygens (at corners, edges or faces) with each other. The lower-valence Mg 2+ and Fe 2+ cations are surrounded by polyhedra which do share oxygens.
A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds, or some combination of these effects.
Structural chemistry is a part of chemistry and deals with spatial structures of molecules (in the gaseous, liquid or solid state) and solids (with extended structures that cannot be subdivided into molecules). For structure elucidation [1] a range of different methods is used.
The rightmost structure in the diagram has a charge of -2 on the nitrogen atom. Applying the principle of electroneutrality this can be identified as only a minor contributor. Additionally as the most electronegative atom should carry the negative charge, then the triple bonded structure on the left is predicted to be the major contributor. [7]
Enantiotopic groups are identical and indistinguishable except in chiral environments. For instance, the CH 2 hydrogens in ethanol (CH 3 CH 2 OH) are normally enantiotopic, but can be made different (diastereotopic) if combined with a chiral center, for instance by conversion to an ester of a chiral carboxylic acid such as lactic acid, or if coordinated to a chiral metal center, or if ...
ALADDIN [14] is a pharmacophore matching program that uses SMARTS to define recognition points (e.g. neutral hydrogen bond acceptor) of pharmacophores. A key problem in pharmacophore matching is that functional groups that are likely to be ionised at physiological pH are typically registered in their neutral forms in structural databases.
Physical chemistry, in contrast to chemical physics, is predominantly (but not always) a supra-molecular science, as the majority of the principles on which it was founded relate to the bulk rather than the molecular or atomic structure alone (for example, chemical equilibrium and colloids).