Standard molar enthalpy of formation of FeGe(s) and FeGe2(s) intermetallic compounds

• FeGe(s) and FeGe2(s) have been synthesized and characterized.
• The heat of dissolutions of Fe(s), Ge(s), FeGe(s) and FeGe2(s) in liquid tin have been measured.
• Δf  H298° of FeGe, FeGe2 were found to be to −15.56 ± 0.92 and −36.89 ± 1.17 kJ mol−1, respectively.

Thermodynamics plays an important role in predicting long term stability of the materials under different reactive conditions. The present paper describes determination of standard molar enthalpies of formation of FeGe(s) and FeGe2(s) compounds employing a high temperature solution calorimeter. The reaction enthalpies of Fe(s), Ge(s), FeGe(s) and FeGe2(s) in liquid Sn at 986 K were measured using a Calvet calorimeter. The standard molar enthalpy of formation of the compounds at 298 K (Δf  H298°) were calculated using the measured reaction enthalpy data. The values of Δf  H298° of FeGe(s) and FeGe2(s) at 298 K were found to −15.56 ± 0.92 and −36.89 ± 1.17 kJ mol−1, respectively. The standard molar enthalpy of formation of FeGe(s) and FeGe2(s) at 298 K obtained experimentally has been compared with the calculated values derived using Vienna ab initio simulation package (VASP).