Alkane stereochemistry#Definitions

Pitzer voltage is called the Kenneth Sanborn Pitzer after the chemist (1914-1997, USA ) named ring strain of a molecule, the neighboring atoms is caused by van der Waals repulsion of eclipsed and gauche arranged substituents ( hydrogen atoms). Per eclipsed this interaction are about four to five kcal / mol ( 17 to 21 kJ / mol).

Due to the Pitzer - voltage is not planar, for example, cyclopentane, although it would be as a planar molecule having a C-C bond angle of 108 °, almost free from Valenzwinkelspannung but preferably a bent shape envelope ( " envelope" form).

In cyclic compounds, the Pitzer - voltage part of the total ring voltage is, the more components the Baeyer strain or Valenzwinkelspannung (mainly represented in the three-ring and four- ring ), the Newman - voltage ( 1.5 - repulsion of non-hydrogen atoms) and the Prelog voltage or transannular interaction (especially with larger rings, the maximum ten-membered ring ) are.