Heptasodium tetra­aluminium tetra­kis­(diphosphate) orthophosphate Na7Al4(P2O7)4(PO4)

摘要

The asymmetric unit of title compound contains three Na⁺, one Al³⁺, three P⁵⁺ and eight O²⁻ atoms, with one Na⁺ atom lying on a twofold rotation axis and one Na⁺ and one P⁵⁺ atom on fourfold rotoinversion axes. The fundamental building units of the title structure are isolated PO4 tetra­hedra, AlO6 octa­hedra and P2O7 groups, which are further inter­locked by corner-sharing O atoms, forming a three-dimensional framework structure. The Na⁺ atoms are located within the cavities of the framework, showing coordination numbers of 4, 6 and 7.