Thermodynamic properties of LaCrO 3

Abstract

The nano powders of LaCrO 3 were prepared by a sol-gel route. The heat capacity of LaCrO 3 nano powders from 350 to 550 K was measured by DSC method and expressed as: C p(LaCrO3) (±0.112) = 166.844 − 8.500 × 10 −3 T − 1.022 × 10 6 T −2 (J/(mol·K)) (350–550 K). An EMF measurement assembly was developed with CaF 2 as an electrolyte for the galvanic cell. From measured EMF data of the reversible cell, (−) Pt, La 2O 3, LaF 3, O 2 (1 atm)|CaF 2|O 2(1 atm), LaF 3, LaCrO 3, Cr 2O 3, Pt(+), and the relevant value of Gibbs free energy, the Gibbs free energy of formation of LaCrO 3 was calculated from 700 to 885 K: Δ G f,LaCrO 3 ▪ = −1555.364 + 0.354 T (kJ/mol) (700–885 K). And the Gibbs free energy change of reaction from simple oxides La 2O 3 and Cr 2O 3 was calculated to be: Δ G f,ox(LaCrO 3) ▪ = −94.758 + 8.530 × 10 −2 T(kJ/mol) (700–885 K).