Standard enthalpies of formation of Sr2CuO3 and Ca2CuO3

The enthalpies of reactions between alkaline-earth cuprates M2CuO3 (M = Ca, Sr) and hydrochloric acid were measured in a hermetic swinging calorimeter at 298.15 K. The M2CuO3 samples were prepared by solid-phase synthesis from calcium or strontium carbonate and copper oxide and characterized by X-ray powder diffraction, EDX and wet analysis. The standard enthalpies of formation obtained for the cuprates, −1431 ± 4 kJ mol−1 for Ca2CuO3 and −1374 ± 3 kJ mol−1 for Sr2CuO3, are discussed and compared with previous experimental and assessed values.