Аннотация:Based on gas electron diffraction experiments supported byquantum chemical simulations, the molecular structure of6-phenyl-1,5-diazabicyclo[3.1.0]hexane (PhDBH) in the gasphase was determined, which is characterized by the puckeringmotion of the five-membered ring typical of bicyclo[3.1.0]hexanes. It was found that the previously determined crystalpacking is accompanied by a certain torsional twisting of themolecule, requiring activation energy. Based on the simulationsof PhDBH clusters, it was shown that the energy is compensatedby intermolecular interactions.