Zr(tfpm)(4) (tfpm = 1,1,1-trifluro-5,6-dimethylheptanedionate) (1), was prepared and characterized by FT-IR, FABMS (Mol.Wt. = 869) and TG-DTA analyses. The TG-DTA curve exhibited a single step volatilization commencing from its melting point of 121, C and volatilizes with a nil residue at 210 degrees C; ZrCp2Cl2 (2) melts at 241 degrees C and it completely volatile at 310,C leaving nil residue. The equilibrium vapor pressure of (1) and (2) over the range of 121.4-152 degrees C and 135.4-176 degrees C were determined to be log(p(e)/mPa) = 12 +/- 1 -3700 +/- 260/T (degrees C) and log(p(e)/mPa) = 13.1 +/- 0.1 - 4533 +/-40/T(degrees C), respectively by employing a TG-based transpiration technique. The enthalpies of vaporization (Delta H degrees(vap)) for (1) and (2) as calculated from the slope of the curve were found to be 71 +/- 5 and 87 +/- 1 kJ mol(-1), respectively. The entropies of vaporization (Delta S-vap) for (1) and (2) as calculated by using Trouton's rule were found to be 180.2 +/- 13 and 169.3 +/- 0.2 J mol(-1) K-1, respectively. (C) 2008 Published by Elsevier B.V.