# Cycloalkanes: Structural Variety

## Cycloalkanes: Cyclobutane

3D Model
Bond lengths and bond angles of cyclobutane

Cyclobutane is a non-planar, bent molecule. By deviating from planarity, the eight hydrogen atoms are eclipsed resulting in decreased strain. Part of the molecule is rotated out of the plane by 26°. However, this does not imply that the structure is rigid; it interconverts rapidly from one bent to another. The C-C-C angle of 88.5° still is clearly different from a tetrahedral angle (109.5°) indicating high ring strain.

Fig.1
Schematic depiction
Fig.2
Animation

The of the C-C bond in cyclobutane is very small with a value of 264 $kJmol-1$. As in cyclopropane, ring opening eliminates the ring strain and allows the formation of new bonds with larger orbital overlap. Though less reactive than cyclopropane, cyclobutane undergoes similar reactions.

Fig.3
Cracking to ethylene
Fig.4
Hydrogenation to butane
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