Electrochemical and calorimetric data for the fluorite trigadolinium ruthenium heptaoxide Gd₃RuO₇(s)

Abstract

The fluorite trigadolinium ruthenium heptaoxide, Gd₃RuO₇(s), an interesting ternary oxide containing two magnetic cations and known to show complex magnetic behavior was synthesized by the solid-state reaction route. A solid-state galvanic cell was set up to determine the standard molar Gibbs energy of formation of Gd₃RuO₇(s) from elements in their standard state, employing oxide ion–conducting electrolyte. A differential scanning calorimeter was employed to determine the isobaric standard molar heat capacity of this ternary oxide. Low-temperature standard molar heat capacity measurements were measured in the temperature range from 126 to 299 K while the high-temperature range was from 307 to 846 K and revealed a first-order phase transition, the smoothed values could be fitted to a mathematical expression:

C°_p,m (Gd₃RuO₇,s,T)(J⋅K⁻¹⋅mol⁻¹) = 252.05 + 3.72 ∙10⁻² T(K)—31.49 ∙10⁵/T²(K).

The isobaric standard molar heat capacity of the titled oxide, C°_p,m, at 298.15 K is 227.7 J⋅K⁻¹⋅mol⁻¹. The calorimetric values along with the Gibbs energy determined were used to determine all other thermodynamic functions for Gd₃RuO₇.

Graphic Abstract

Combined isobaric standard molar heat capacity of Gd3RuO7(s) in the entire temperature range from 126 K to 846 K