Steric repulsion effect

The X—N bond distances (Tables 4-8) in XH3NNN and XH3NCZ show the azide being consistently the larger. This is probably because of the smaller XNN bend angle which can introduce steric repulsion effects, and shows that structures with X=N double... 

Investigations of a large number of complexes indicate that the sfructure changes of the acceptor molecule generally are in the direction predicted by the VSEPR model while the structure changes of the donor are due to a combination of VSEPR and steric repulsion effects. 

When there is an excess of polymer (cf. Fig. 3.13d), each particle is surrounded by a saturated layer of adsorbed polymer. If two particles approach one another, the loops fixed onto each particle enter into contact, interact and generally repel one another, long before the electrostatic repulsion can become relevant. This steric repulsion effect can be traced to a combination of two factors schematised in Fig. 3.14. 

---