The enthalpy of sublimation of cubane

The sublimation enthalpy of cubane, a key reference material for force field and quantum mechanical computations, was measured by combining the vaporization enthalpy at T = 298.15 K to the sum of the fusion enthalpy measured at T = 405 K and a solid-solid phase transition that occurs at T = 394 K. The fusion and solid-solid phase transitions were measured previously. A sublimation enthalpy value of (55.2 +/- 2.0) kJ mol(-1) at T = 298.15 K was obtained. This value compares quite favorably the value obtained by comparing the sublimation enthalpy of similar substances as a function of their molar masses but is at odds with earlier measurements. (C) 2004 Elsevier B.V. All rights reserved.