Pure, highly explosive CF3C(O)OOC(O)CF3 is prepared for the first time by low-temperature reaction between CF3C(O)Cl and Na2O2. At room temperature CF3C(O)OOC(O)CF3 is stable for days in the Liquid or gaseous state. The melting point is -37.5 degreesC, and the boiling point is extrapolated to 44 degreesC from the vapor pressure curve log p = -1875/T + 8.92 (P/mbar, T/K). Above room temperature the first-order unimolecular decay into C2F6 + CO2 occurs with an activation energy of 129 kJ mol(-1). CF3C(O)OOC(O)CF3 is a clean source for CF3 radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G* basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) Angstrom and dihedral angle phi (C-O-O-C) = 86.5(32)degrees. The density functional calculations reproduce the experimental structure very well.