Illustrated Glossary of Organic Chemistry

Gauche: The relationship between two atoms or groups whose dihedral angle is more than 0^o (i.e., eclipsed) but less than 120^o (i.e., the next eclipsed conformation). A conformation which has one or more gauche interactions is can be called a gauche conformation.

	The anti-staggered conformation of butane has six gauche relationships.

	This is a gauche conformation because the methyl groups are gauche. This conformation has a total of six gauche relationships.