Identification of erbium(III) chloride solvate ErCl3(thf)(3.5): Crystal and molecular structure of the ion-pair [trans-ErCl2(thf)(5)][trans-ErCl4(thf)(2)]

ErCl3(thf)(3.5) has been identified by an X-ray diffraction study as the ionic salt [trans-ErCl2(thf)(5)] [trans-ErCl4(thf)(2)]. The monocation features a seven-coordinate erbium atom with a trans-ErCl2 unit (Er-Cl, 2.563(2) Angstrom) surrounded by five tetrahydrofuran molecules (Er-O, in the range 2.383(8)-2.393(8) Angstrom) in a regular pentagonal bipyramidal geometry. The anion is six-coordinate with an octahedral metal geometry comprising four equatorial chlorine atoms (Er-Cl, 2.593(3) and 2.609(3) Angstrom) and two axial tetrahydrofuran molecules (Er-O, 2.313(9) Angstrom)