Читать книгу Foundations of Chemistry - Philippa B. Cranwell - Страница 127

Intermolecular forces are the weak forces of attraction formed between simple covalently bonded molecules. There are three types of intermolecular forces:

 London dispersion forces: instantaneous dipole–induced dipole forces

 Permanent dipole–permanent dipole forces

 Hydrogen bonding

The order of strengths of these forces is:

instantaneous–induced dipole forces < permanent dipole–permanent dipole forces < hydrogen bonding. Table 2.2 gives approximate values for the strengths or energies of different types of intermolecular forces and bond types.

Table 2.2 Approximate strengths of different types of bonds and intermolecular forces.

Bond type/intermolecular force type	Strength (approx.)/kJ mol−1
Ionic bond (e.g. NaCl)	771
Single covalent bond (e.g. Cl—Cl)	242
Instantaneous dipole–induced dipole	0–10
Permanent dipole–permanent dipole	5–20
Hydrogen bond	20–45