Endo-Tricyclo[5.2.1.0(2,6)]decane (CAS 6004-38-2) is an important intermediate compound for synthesizing diamantane. The lack of data on the thermodynamic properties of the compound limits its development and application. In this study, endo-Tricyclo[5.2.1.0(2,6)]decane was synthesized and the low temperature heat capacities were measured with a high-precision adiabatic calorimeter in the temperature range from (80 to 360) K. Two phase transitions were observed: the solid-solid phase transition in the temperature range from (198.79 to 210.27) K, with peak temperature 204.33 K; the solid-liquid phase transition in the temperature range from 333.76 K to 350.97 K, with peak temperature 345.28 K. The molar enthalpy increments, DeltaH(m), and entropy increments, DeltaS(m), of these phase transitions are DeltaH(m) = 2.57 kJ(.)mol(-1) and DeltaS(m) = 12.57 J(.)K(-1.)mol(-1) for the solid-solid phase transition at 204.33 K, and, Delta(fus)H(m) = 3.07 kJ(.)mol(-1) and Delta(fus)S(m) = 8.89 J(.)K(-1.)mol(-1) for the solid-liquid phase transition at 345.28 K. The thermal stability of the compound was investigated by thermogravimetric analysis. TG result shows that endo-Tricyclo[5.2.1.0(2,6)]decane starts to sublime at 300 K and completely changes into vapor when the temperature reaches 423 K, reaching the maximal rate of weight loss at 408 K. (C) 2003 Elsevier Ltd. All rights reserved.