The viscosity and vapor pressure of the reactive chelating ligand, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (H(+)hfac) have been determined. The viscosity of liquid H(+)hfac was determined to be (1.39 +/- 0.19) x 10(-3) Pa.s at 24 degrees C and (8.35 +/- 0.25) x 10(-4) Pa.s at 35 degrees C. The vapor pressure of H(+)hfac was found to range from 4 kPa at 0 degrees C to 49.5 kPa at 57 degrees C. The viscosity was measured using a capillary tube viscometer, and the vapor pressure was measured using a mass transfer gas saturation apparatus. These methods were employed because conventional methodologies would have produced unreliable data due to the formation of the tetrol hydrate of H(+)hfac inside the apparatus and potentially exposed laboratory personnel to hazardous working conditions.