New Open-Framework Mixed-Valence Chromium(III) Cerium(III)/(IV) Sulfate: CrCeIII7CeIV6(HSO4)6(SO4)21·75H2O
Journal article, 2007
The title compound, synthesized from CrVI and CeIV species, crystallizes in the space group P63 with a = 19.3015(2), c = 25.2684(4) Å, and Z = 2. The structural design of the title compound differs essentially from structures of known mixed-valence cerium compounds which all form three-dimensional networks. In the title compound the cerium atoms, interlinked by sulfate groups, extend to form layers held together by hydrogen-bonding contacts. Perpendicular to these layers there are 10 Å wide channels. One third of the channels host solvent water only, while the other two thirds of the channels also host [Cr(H2O)6]3+ and [Ce(SO4)3(H2O)6]3- units, blocking each of these channels once per unit cell, resulting in 14 Å long voids.