The weak ligand field in lanthanoid(III) hydrogensulfate‐sulfates

Abstract

AbstractThe hydrogensulfate‐sulfates Ln(HSO4)(SO4) (Ln: Sm, Eu, Gd, Tb, Dy) have been crystallized from sulfuric acid and their thermal decomposition behavior has been studied. The crystal structures for all members of the series were refined from X‐ray single‐crystal diffraction data (for all: Tb(HSO4)(SO4) structure type, P21, Z=2, a≈6.66 Å, b≈6.63 Å, c≈6.82 Å, β≈104.6°). Optical spectra (Sm–Dy) and magnetic susceptibilities (Eu–Dy) have been measured. For comparison the octahydrates Ln2(SO4)3 ⋅ 8 H2O (Sm, Eu) and the anhydrous sulfates Ln2(SO4)3 (Sm, Eu) have also been characterized by optical spectroscopy and magnetic measurements. Ligand field analyses (angular overlap model) based on these data suggest for the square‐antiprismatic [LnIIIO8] chromophores in the hydrogensulfate‐sulfates a rather weak ligand field, which is comparable only to that in ultraphosphates LnP5O14 and in contrast to the much stronger field observed for most other lanthanoid(III) oxo‐compounds studied so far.