The molecular structure of phosphabenzene. A theoretically predicted correction to the experimentally determined CC bond lengths

Abstract Quantum-mechanical calculations at the Hartee—Fock and MP2 level of theory using various basis sets predict that the CC interatomic distances are nearly identical ( r C 2 C 3 = 1.396 A, r C 3 C 4 = 1.398 A). This is at variance with the results of a combined electron diffraction and microwave study, which suggest that the C 2 C 3 bond is longer (1.413 A) than the C 3 C 4 bond (1.384 A).