Saturated Vapor Pressure and Sublimation Enthalpy of Fluorine Derivatives of C₆₀

Abstract

Knudsen cell mass spectrometry and Knudsen effusion method were used to determine the saturated vapor pressures of fluorine derivatives C 60 F 36 and C 60 F 48 in the temperature intervals 408−539 K and 395−528 K, respectively; the recommended values are described by the temperature equations: ln( p {C 60 F 36 }/Pa) = (−16292 ± 939)/( T /K) + (30.90 ± 1.97) and ln( p {C 60 F 48 }/Pa) = (−13146 ± 827)/( T /K) + (24.34 ± 1.71). The sublimation enthalpies were also determined: Δ sub H o 466 {C 60 F 36 } = (135 ± 8) kJ/mol and Δ sub H o 476 {C 60 F 48 } = (109 ± 7 ) kJ/mol. Ancillary experiments demonstrated that C 60 F 48 vaporizes without decomposition.