Measurements leading to the calculation of the standard thermodynamic properties for gaseous bicyclopentyl (Chemical Abstracts registry number [1636-39-1]) are reported. Experimental methods include adiabatic heat-capacity calorimetry, comparative ebulliometry, and differential-scanning calorimetry (d.s.c.). The critical temperature was determined by d.s.c. and the critical pressure and critical density were estimated. Standard molar entropies, standard molar enthalpies, and standard molar Gibbs free energies of formation are reported at selected temperatures between T = (298.15 and 600) K. Formation properties were calculated with a literature value for the enthalpy of combustion in the liquid phase. All results are compared with available literature values. (C) 2004 Elsevier Ltd. All rights reserved.