Structural analysis of AlCl3–n-butylpyridinium chloride electrolytes by X-ray diffraction

Abstract

The structures of AlCl₃–n-butylpyridinium chloride (BPC) mixtures have been investigated using the radial distribution function (r.d.f.) based on X-ray scattered intensity data and have been analysed by the correlation method. By an analysis of r.d.f., it was confirmed that the AlCl₄ tetrahedron is the fundamental structural unit in AlCl₃–BPC melt. The nearest-neighbour distances of Al—Cl and Cl—Cl pairs for AlCl^–₄ in a 1:1 AlCl₃–BPC melt at 60 °C and for Al₂Cl^–₇ in a 2:1 AlCl₃–BPC melt at 20 °C were 2.15 and 3.51 Å, respectively. The Al₂Cl^–₇ ion in a 2:1 AlCl₃–BPC melt at 150 °C decomposed partly to AlCl^–₄ and Al₂Cl₆.