Hydrogen bonding classification

TABLE 13-20 Hydrogen Bonding Classification of Chemical Families... 

Keywords Hydrogen bonding definition of hydrogen bond classification of hydrogen bonding... 

Most of hydrogen-bonded molecules exhibit to a larger or lesser extent all of the properties described in section VI. There exist cases, however, when some of these features are not present or even the trend is opposite. An example are complexes in which the X-H vibrations are blue shifted (see Hobza et al, 1999, and Gu et al, 1999). Some authors questioned if such complexes should be considered hydrogen bonded. According to the definition adopted in this article, the hydrogen-bonded classification will be appropriate if the equilibrium geometry has a nearly linear X-H- -Y shape, and the bond is reasonably strong (i.e., not much weaker than about 1 kcal/mol). 

On the basis of the hydrogen-bonding classification, specify a solvent which will be selective for the organic substance in the following mixtures. Substantiate the choice by calculating selectivities from observed ternary data. 

The term polarity includes parameters such as dipole moment, hydrogen bonding, polarisability, entropy and enthalpy. Since the term polarity cannot be defined unambiguously in physical terms, a classification on this basis is not meaningful. 

Another type of classification of hydrogen bonds is based upon the relative strength of the interaction ... 

Table 4.8 Classification of solvent based on hydrogen bonding...

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