Structure of Tetrahydrofuran

Tetrahydrofuran is abbreviated THF. THF is a very common ether solvent. Note that the 5-membered ring is not planar so that the CH bonds are less eclipsing. Note that there is one plane of symmetry in this structure. The molecule is symmetric about the plane that is perpendicular to the frame of C-atoms and cuts through the O-atom and the midpoint of the CC bond opposite to the oxygen.


Figure. The RHF/6-31G* optimized structure of tetrahydrofuran (THF). While this is a stable minimum structure of THF, this is not the best structure. THF prefers the structure with the twofold axis instead of the symmetry plane.