Counter cation Al3+ assisting formation of a 2D water sheet that contains both cyclic water hexamers in boat and chair conformations and cyclic water tetramers in an Anderson-type polyoxometalate [Al(H2O)6][Al(OH)6Mo6O18]·10H2O

For the first time, a 2D water sheet that contains both cyclic water hexamers around Al3+ in boat and chair conformations and cyclic water tetramers was crystallographically observed in an Anderson-type supramolecular complex, [Al(H2O)6][Al(OH)6Mo6O18]·10H2O 1, in which the element type of both the counter cation and the heteroatom of the polyanion are the same, that is Aluminum. The counter cation Al3+ is coordinated by six water molecules forming a nearly ideal octahedron. The octahedron is then hydrogen-bonded to its surrounding lattice water molecules producing a novel Al3+-containing 1D water chain composed of both boat- and chair-like water hexamers. More interestingly and importantly, the water chains further on join together through a parallelogram composed of four water molecules to yield a unique 2D water sheet.