Subject index chemical bonds

Fig. 1.4. Number of papers abstracted by Chemical Abstracts under the subject index Hydrogen Bonding ...

In order to locate items of interest in the book, the subject index lists, in addition to chemical operations, types of compounds rather than specific compounds (with a few exceptions). If, for example, readers do not find what they are looking for under the entry fluoroolefins , they may try olefins , double bonds, additions of , etc. 

If a polymer mass containing only truly covalent bonds free from dipoles is placed in an electric field there is an instantaneous electron shift (electron polarization) but no actual movement of the molecules themselves. If this field is between two charged plates the polymer acts as a dielectric in a capacitor and the capacity of the charged plates is increased. The factor by which the capacity is increased is known as the dielectric constant or permittivity. Because it depends on virtually instantaneous electron movement the value of the dielectric constant is not dependent on temperature nor on the frequency (if the field is subject to alternation). The dielectric constant of such materials is frequently equal to the square of the refractive index and both properties may be calculated from a knowledge of the chemical bonds present. The method of making such a computation is given in most standard texts on physical chemistry. 

As annotated databases, WOMBAT and WOMBAT-PK continue to evolve in time - not only with the addition of more entries but also with updates and restructuring of the biological, clinical, and chemical information, which is subject to revision even after the data are captured and indexed. The inclusion of the precomputed properties panel allows the users to quickly identify rule-of-five or rule-of-three compliant datasets, or to constrain the query with respect to, for example, flexible bonds, PSA, computed solubility or LogP, and so on. WOMBAT and WOMBAT-PK are currently available in the MDL Isis/Base format. WOMBAT is also integrated in CABINET (Chemical And Biological... 

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