The synthesis of CF3OC(O)OOC(O)F is accomplished by the photolysis of a mixture of (CF3CO)(2)O, FC(O)C(O)F, CO, and O-2 at -15 degreesC using a low-pressure mercury lamp. The new peroxide is obtained in pure form in low yield after repeated trap-to-trap condensation and is characterized by NMR, IR, Raman, and UV spectroscopy. Geometrical parameters were studied by ab initio methods [B3LYP/6-311+G(d)]. At room temperature, CF3OC(O)OOC(O)F is stable for many days in the liquid or gaseous state. The melting point is -87 degreesC, and the boiling point is extrapolated to 45 degreesC from the vapor pressure curve log p = 8.384 - 1715/T (p/mbar, T/K). A possible mechanism for the formation of CF3OC(O)OOC(O)F is discussed, and its properties are compared with those of related compounds.