Solvate Complex LiAlCl₄·SO₂: Synthesis and Physical-Chemical Properties

This work describes the synthesis of the LiAlCl₄·SO₂ solvate complex and its properties. Its composition was determined using thermogravimetric analysis, Raman spectroscopy, and UV-vis spectroscopy. The specific ionic conductivity of LiAlCl₄·SO₂ is 4.7 × 10^-2 S·cm^-1. The dynamic viscosity is 19 cP at 25 °C, and the lithium transference number is 0.78. The melting point (+2.5 °C) and decomposition temperature (+60 °C) of LiAlCl₄·SO₂ were determined by simultaneous thermogravimetric analysis and differential scanning calorimetry. The structure of the solvate complex LiAlCl₄·SO₂ has been studied using a molecular dynamics method. A lithium cation is coordinated by one atom of Cl of the anion AlCl₄^- and one oxygen atom of SO₂. The coordination number of lithium ions of LiAlCl₄·SO₂ is 4. The lithium cation is coordinated by three anions of AlCl₄^- and one molecule of SO₂. Anion AlCl₄^- acts as a bridging ligand and binds different lithium cations.