@S06037-1@ due to a departure in bond @A00346@ 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 @A00346@ of \(109^{\,\unicode{x26ac}}\,28^{\prime }\); in this sense @A00346@ @S06037-2@ is also known as @B00586@.