Crystal structures of the tetrachloridoaluminates(III) of rubidium(I), silver(I), and lead(II)

Abstract

Abstract The reactions of the binary metal chlorides AgCl, RbCl and PbCl2 at T = 180°C in the ionic liquid [BMIm]Cl · 4AlCl3 (BMIm = 1-n-butyl-3-methylimidazolium) yielded air-sensitive, colorless, high-quality crystals of their tetrachloridoaluminate(III) salts. Thereby, the obstructions that hinder proper crystallization of these compounds from pristine AlCl3 melts were circumvented. X-ray diffraction on single-crystals revealed a monoclinic structure (space group P21/c) for Ag[AlCl4], which unexpectedly has a closer relation to Cu[AlCl4]2 than to Cu[AlCl4]. Rb[AlCl4] crystallizes in the baryte structure type (orthorhombic, Pnma), and Pb[AlCl4]2 is isotypic to α-Sr[GaCl4]2 (orthorhombic, Pbca).