| Abstract: | This study presents the coordination modes and crystal organization of a calcium–potassium coordination polymer, polyhexaaquabis(μ4‐4‐carboxybenzenesulfonato‐κ4O1:O1′:O1′′:O4)bis(μ3‐4‐carboxybenzenesulfonato‐κ2O1:O1′)calcium(II)dipotassium(I)], CaK2(C7H5O5S)4(H2O)6]n, displaying a novel two‐dimensional framework. The potassium ion is seven‐coordinated by four sulfonate and one carboxyl O atom located on five different acid ligands, two of which are unique, and by two symmetry‐independent water O atoms. A pair of close potassium ions share two inversion‐related sulfonate O‐atom sites to form a dimeric K2O12 unit, which is extended into a one‐dimensional array along the a‐axis direction. The six‐coordinate Ca2+ ion occupies a special position () at (0, , ) and is surrounded by four sulfonate O atoms from two inversion‐related pairs of unique acid monoanions and by two O atoms from aqua ligands. The compound displays a layered structure, with K2O12 and CaO6 polyhedra in the layers and aromatic linkers between the layers. The three‐dimensional scaffold is open, with nano‐sized channels along the c axis. |
