Heats of solution of TlI in TlNO3 and TlBr in TlI crystals. Phase diagrams of TlNO3–TlI and TlBr–TlI systems

From differential scanning calorimetry (DSC) measurements of the decrease in the heat (enthalpy) of transition in the solid phase, the partial molar heats of solution at infinite dilution, χ, and the heats of solution or substitution, ΔHs° of I− in TlNO3 crystal, Br− and NO3− in TlI crystal along with their recovered lattice energies ΔHL° are reported. The phase diagram of the TlNO3–TlI system with details of the subsolidus region along with subsolidus region of the TlBr–TlI diagram are reported. The TlIx(NO3)1−x compositions exhibit properties, viz. structure, transition temperatures and melting temperature characteristic of a “mixed crystal” or “crystalline solid-solution” paralleling Tl(1−x)RbxNO3 behavior.