Electron diffraction by gases: The molecular structure of bicyclo[3.1.1]heptane

The molecular structure of bicyclo[3.1.1]heptane has been investigated by means of electron diffraction of the vapour. The molecule has one plane of symmetry and an average carbon‐carbon bond length of 1.537 Å. Details of the structure are compared with those in similar molecules and differences between the carbon‐carbon bond lengths are discussed with reference to semi‐empirical predictions based on the results of MO calculations.