Enthalpy of Phase Transitions and Heat Capacity of Stoichiometric Compounds in LaBr3-MBr Systems (M=K, Rb, Cs)

摘要: Molar enthalpies of solid-solid and solid-liquid phase transitions the LaBr 3 , K 2 5 Rb 6 Cs compounds were determined by differential scanning calorimetry. exist at ambient temperature melt congruently 875 864 K, respectively, with corresponding 81.5 77.2 kJ mol -1 . are only 3:1 existing in investigated systems. The first one forms from RbBr 700 an enthalpy 44.0 melts 940 46.7 second exists room temperature, undergoes a transition 725 9.0 1013 57.6 Two other CsBr-based systems (Cs CsLa Br 7 ) decompose peritectically 765 828 respectively. heat capacities above solid as well liquid A special method - 'step method' developed SETARAM was applied these measurements. capacity experimental data fitted polynomial dependence.