Anti-Periplanar Conformation Definition

Two of the terms you may encounter in organic chemistry are anti-periplanar and syn-periplanar. Both refer to the geometry of chemical bonds in a molecule. Key Takeaways: Anti-Periplanar Definition Anti-periplanar and syn-periplanar are a pair of terms used to describe chemical bond geometry of a molecule.The anti-periplanar conformation is a periplanar conformation in which the dihedral angle between two atoms or groups of atoms is  between  ±150 ° and 180 °. In this conformation, the groups are anti-coplanar.The syn-periplanar conformation is a periplanar conformation in which the dihedral angle between the atoms or groups is between  ±30 °. In this conformation, both groups are on the same side of the molecule. Anti-Periplanar Definition Anti-periplanar refers to a periplanar conformation where the dihedral angle between two atoms or groups of atoms is  between  ±150 ° and 180 °. In texts, anti-periplanar means bonds are anti-coplanar. The image shows butane (C4H10) in a syn-periplanar conformation where the two methyl groups (-CH3) are lined up with a 180 ° angle. Syn-coplanar is related to anti-periplanar. The dihedral angle between the atoms or groups is between  ±30 °Ã‚  and the groups are both on the same side of the plane as each other. Sources Eliel, Ernest; Wilen, Samuel; Mander, Lewis (September 1994).  Stereochemistry of Organic Compounds. New York: Wiley-Scientific.Kane, Saul; Hersh, William (1 October 2000). Periplanar or Coplanar?. Journal of Chemical Education. 77 (10): 1366.