Crystal structure of poly[μ₃-acetato-diaqua-μ₃-sulfato-cerium(III)]: serendipitous synthesis of a layered coordination polymer exhibiting interlayer O—H...O hydrogen bonding

Single crystals of the title compound, [Ce(CH₃COO)(SO₄)(H₂O)₂] _<i>n</i> , were obtained serendipitously by the reaction of Ce(NO₃)₃·6H₂O with 2,5-thio-phenedi-carb-oxy-lic acid (H₂TDC) and acetic acid in a mixture of ethanol and water, where it is assumed that the sulfate ions leached from the Teflon reactor, which was treated with per-oxy-monosulfuric acid prior to its use. Its asymmetric unit consists of one Ce^III cation, one sulfate dianion, one acetate anion and two crystallographically independent water mol-ecules, all of them located in general positions. The cerium cations are coordinated by three acetate anions (one <i>O</i>,<i>O</i>-chelating) and three sulfate dianions that are related by symmetry as well as two independent water mol-ecules within an irregular CeO₉ coordination geometry. The Ce^III cations are linked by the acetate ions into [010] chains, which are further connected into (001) layers by the sulfate dianions. Intra-layer and inter-layer O-H⋯O hydrogen bonds are observed. Powder X-ray diffraction shows that only traces of the title compound have formed together with a large amount of an unknown crystalline phase. Attempts to prepare the title compound in larger amounts and as a pure phase were unsuccessful.