Although aqueous lanthanum chloride solutions have been well studied at room temperature , studies targeting hydrothermal temperatures and pressures are quite scarce in available literature. In the absence of experiments at high temperatures, earlier studies relied on extrapolations of room temperature data using a species-based equation of state (EOS), such as the Helgeson-Kirkham-Flowers (HKF) model . Haas et al. fitted a set of parameters for the HKF model at 25 • C, 1 bar. Mayanovic et al. performed in situ X-ray absorption spectroscopy (XAS) of La 3+ in Cl-bearing solutions up to 500 • C. They predicted a gradual increase in chloride complexation from zero at 25 • C to 3.1 at 500 • C. Migdisov et al. performed high-temperature solubility experiments and published a set of HKF parameters that can be used up to 300 • C. As far as computational studies are concerned, Guan et al. is the only study available in literature.