Enthalpies of Mixing in the LaI3鈥揗I (M = Li, Na, K, Rb, Cs) Binary Systems
文摘
The molar enthalpy of mixing (螖mixHm) in the LaI3鈥揗I (M = Na, K, Cs) liquid systems was measured over the whole composition range at 1060 K with a Calvet-type high temperature microcalorimeter. The mixing of two liquid components was achieved by using the 鈥渂reak-off ampoule technique鈥? The dependence of the interaction parameter on composition 位 = A + Bx + Cx2 + Dx3 (x = mole fraction of LaI3) was determined. Unknown molar enthalpy of mixing (螖mixHm) in the LaI3鈥揕iI and LaI3鈥揜bI liquid systems was calculated using the conformal solution theory of Davis. In all systems under investigation the enthalpies of mixing are negative except the LaI3鈥揕iI system at LaI3-rich compositions. The minimum of enthalpy is shifted toward the alkali metal iodide-rich part and is located at the composition of x(LaI3) 鈮?0.35鈥?.40. Measured and calculated molar enthalpies of mixing were compared with the molar enthalpies of mixing in the LaCl3鈥揗Cl and LaBr3鈥揗Br (M = Li, Na, K, Rb, Cs) liquid systems.