Thermodynamic properties of silicides. VI. Pentamolybdenum trisilicide (Mo 5Si 3). Fluorine combustion calorimetric determination of the standard molar enthalpy of formation at the temperature 298.15 K

• Published in: The Journal of chemical thermodynamics 1997, Vol.29 (1), p.87-98
• Main Authors: Tomaszkiewicz, Iwona, Hope, G.A., Beck II, Charles M., O'Hare, P.A.G.
• Format: Article
• Language: English
• Subjects: calorimetry; Chemistry; Elements and non-metal compounds (oxides, hydroxides, hydrides, sulfides, carbides, ...); enthalpy of formation; Exact sciences and technology; fluorine bomb combustion; Inorganic chemistry and origins of life; pentamolybdenum trisilicide; Preparations and properties; thermodynamic properties
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1006/jcht.1996.0146

The standard molar enthalpy of formation Δ f H m oof pentamolybdenum trisilicide Mo 5Si 3has been determined by fluorine combustion calorimetry to be −(314.3 ± 8.3) kJ·mol −1at T= 298.15 K and p o= 101.325 kPa. Conventional thermodynamic properties of Mo 5Si 3are 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 5Si 3(s) + 7SiO 2(s) on the basis of the most up-to-date thermodynamic values.