Calcium chloride rhenate(VII) dihydrate

The crystal structure of calcium chloride rhenate(VII) dihydrate, CaCl(ReO₄)·2H₂O, investigated at 85 K, consists of calcium cations, chloride anions, rhenate(VII) anions and water molecules. In the nearly tetrahedral rhenate(VII) anion, all constituent atoms lie on special positions of m2m (Re) and m (O) site symmetries. The Cl⁻ anion and water O atom lie on special positions of m2m and 2 site symmetries, respectively. The Ca²⁺ ion, also on a special position (m2m), is eight‐coordinated in a distorted square‐antiprismatic coordination mode. The crystal has a layered structure stabilized by Ca—O coordination bonds and O—H...Cl hydrogen bonds.