Flexibility of the Carbodiphosphorane, (Ph₃P)₂C: Structural Characterization of a Linear Form

X-ray diffraction studies demonstrate that crystals of the carbodiphosphorane, (Ph₃P)₂C, obtained from solutions in benzene, exhibit a linear P–C–P interaction. This observation is in contrast to the highly bent structures that have been previously reported for this molecule, thereby providing experimental evidence that the coordination geometry at zerovalent carbon may be very flexible. Density functional theory calculations support the experimental observations by demonstrating that the energy of (Ph₃P)₂C varies relatively little over the range 130–180°.