Mixing enthalpies of solid solutions (Cs1−x, Rbx)NO3 at T = (298.15 and 473.15) K

•Several calorimetric measures are realized on Cs1−xRbxNO3 at T = (298.15 and 473.15) K.•Solution enthalpies of Cs1−xRbxNO3 at T = 473.15 K are measured, for the first time.•Solution enthalpies of Cs1−xRbxNO3 at T = 298.15 K are obtained, for the first time.•Mixing enthalpies of the Cs1−xRbxNO3 solid solutions are determined, for the first time.•Both mixing enthalpies of solid solutions present a positive deviation from ideality.

A previous investigation of the binary phase diagram (Cs, Rb)NO3 has confirmed the existence of two continuous solid solutions α(Cs1−x, Rbx)NO3 and β(Cs1−x, Rbx)NO3 stable in the temperature ranges T = (298 to 421) K and T = (439 to 503) K respectively. The mixing enthalpies of these solid phases, determined by a calorimetric method at T = (298.15 and 473.15) K, are presented for the first time. A positive and asymmetric deviation from ideality is observed.