Bis(trifluoroaceto) disulfide CF3C(O) OSSOC(O) CF3 was prepared and studied by Raman, photoelectron spectroscopy (PES), and theoretical calculations. This molecule exhibits gauche conformation with both C=O groups cis to the S-S bond; the structure of the OSSO moiety is characterized by dihedral angle delta(OSSO)=-95.1 degrees due to the sulfur-sulfur lone pair interactions. The contracted S-S bond (1.979 angstrom) and relatively high rotational barrier (19.29 kcal mol(-1) at the B3LYP/6-31G* level) of the delta(OSSO) indicate the partial resonance-induced double bond character in this molecule. After ionization, the ground cationic-radical form of CF3C(O) OSSOC(O) CF3 center dot(+) adopts a trans planar main-atom structure (delta(OSSO) = 180 degrees and delta(OCOS) = 0 degrees) with C-2h symmetry. The S-S bond elongates to 2.054 angstrom, while the S-O bond shortens from 1.755 angstrom in neutral form to 1.684 angstrom in its corresponding cationic-radical form. The adiabatic ionization energy of 9.91 eV was obtained accordingly. The first two HOMOs correspond to the electrons mainly localized on the sulfur 3p lone pair MOs: 3p pi {36a (n(S)(A))}(-1) and 3p pi* {35b (n(S)(B), n(O(C=O))(B))}(-1), with an experimental energy separation of 0.16 eV. The first vertical ionization energy is determined to be 10.81 eV.