A unique polyoxotungstate constructed by parallel stacking helices

In this paper, we reported a novel polyoxotungstate, H6[Ni3W4P4O28]·en·4H2O, which is the first 3-D racemic network that incorporates helical WO6-octahedral chains of different handedness as building blocks. The helices are held together by helically distributed phosphorus and nickel atoms, this steric orientation leads to the generation of a small square hole with the dimensions of 0.85 × 0.85 Å and an irregular pentagonal porous channel with the dimensions of 4.08 × 5.26 Å, in which some water and ethylenediamine molecules filled.