@[email protected] due to a departure in bond @[email protected] from 'normal' values. The term is often used in the context of non-aromatic cyclic compounds in which the internal angles differ from the regular tetrahedral @[email protected] of \(109^{\,\unicode{x26ac}}\,28^{\prime }\); in this sense @[email protected] @[email protected] is also known as @[email protected]