The gas-phase thermochemistry of PCl4+: A test of lattice energy calculations

The bond dissociation energy for loss of Cl atom from PCl4+ has been measured to be 411 ± 17 kJ mol−1 at 0 K using energy-resolved collision-induced dissociation in a flowing afterglow-guided ion beam tandem mass spectrometer. Density functional calculations give bond energies that are lower than experiment, while MP2 calculations are in good agreement. The bond energy can be combined with the ionization energy of PCl3 to derive the 0 K heat of formation of PCl4+, 378 ± 18 kJ mol−1. This value is in good agreement with the value derived from lattice energy calculations.