Читать книгу Foundations of Chemistry - Philippa B. Cranwell - Страница 130

One final intermolecular force should be considered, although it follows the same rules and conventions as the intermolecular forces already discussed: the ion–dipole force. The ion can be either positively charged (a cation) or negatively charged (an anion). The dipole that it interacts with can be induced, instantaneous, or permanent. It really depends upon the molecules involved.

For example, a sodium ion (Na⁺) could interact with ethane (a non‐polar molecule) through either of the following:

 An instantaneous dipole, where the ethane itself could develop an instantaneous dipole due to random electron movement within the bonds in the ethane molecule

 An induced dipole, where the ethane itself could develop an induced dipole due to the close proximity of the sodium ion to it

Another example could be the sodium ion (Na⁺) ion interacting with methanol (a polar molecule). The methanol itself has a permanent dipole, so the interaction would be between the δ− of the oxygen on methanol and the Na⁺ ion itself.