Thermodynamic properties of silicides. VI. Pentamolybdenum trisilicide (Mo5Si3). Fluorine combustion calorimetric determination of the standard molar enthalpy of formation at the temperature 298.15 K

Abstract The standard molar enthalpy of formation Δ f H m o of pentamolybdenum trisilicide Mo 5 Si 3 has been determined by fluorine combustion calorimetry to be −(314.3 ± 8.3) kJ·mol −1 at T = 298.15 K and p o = 101.325 kPa. Conventional thermodynamic properties of Mo 5 Si 3 are tabulated to T = 2100 K. Thermodynamic quantities to the same temperature maximum are also given for the high-temperature oxidation reactions: 2MoSi 2 (s) + 70 2 (g) = 2MoO 3 (s) + 4SiO 2 (s), and 5MoSi 2 (s) + 70 2 (g) = Mo 5 Si 3 (s) + 7SiO 2 (s) on the basis of the most up-to-date thermodynamic values.