A simple synthesis of tetrahydrofuran complexes of lanthanoid trichlorides: convenient substitutes for anhydrous lanthanoid chlorides

Reaction of lanthanoid metals with hexachloroethane in tetrahydrofuran under ultrasonication conditions gives LnCl3(thf)n(Ln = La, Nd, Sm, n= 2; Ln = Gd, Yb, n= 3; Ln = Er, n= 3.5, thf = tetrahydrofuran) in good yield; the X-ray crystal structure of [YbCl3(thf)2]2, derived from YbCl3(thf)3 by prolonged treatment with pentane, reveals a chloride-bridged octahedral dimer with trans thf ligands.