A vibrational study of the dinuclear gold ylide complexes [Au(CH 2) 2PPh 2] 2 and [Au(CH 2) 2PPh 2] 2X 2 (X = Cl, Br or I) has been undertaken by Raman spectroscopy. The non-bonding AuAu interaction in the Au I dimer, [Au(CH 2) 2PPh 2) 2, at 64 cm −1 shifts to higher wavenumber in the single-bonded Au II halogen complexes, with bands at 162, 132 and 103 cm −1 for X = Cl, Br and I, respectively, being assigned to ν(AuAu). The Au-X vibration was also identified. The general trends in AuAu and Au-X stretching vibrations with changing halogen are compared with those for other dinuclear metal-metal bonded complexes, with a metal-metal bond order of one, and with those for mononuclear gold-halogen complexes.