Heptasodium tetra­aluminium tetra­kis­(diphosphate) orthophosphate, Na(7)Al(4)(P(2)O(7))(4)(PO(4))

The asymmetric unit of title compound contains three Na(+), one Al(3+), three P(5+) and eight O(2−) atoms, with one Na(+) atom lying on a twofold rotation axis and one Na(+) and one P(5+) atom on fourfold rotoinversion axes. The fundamental building units of the title structure are isolated PO(4) tetra­hedra, AlO(6) octa­hedra and P(2)O(7) 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.