Na-4[In-8(HPO4)(14)(H2O)(6)]. 12(H2O) (trigonal, Pc1, a = 13.8500(2), c = 18.4930(3) Angstrom, V = 3072.12(4) Angstrom(3), and Z = 2), was prepared directly in its sodium form by hydrothermal methods at 398 K, and its structure solved by single crystal methods. The three-dimensional framework structure consists of a network of InO6 and InO5(OH2) octahedra, and PO3(OH) tetrahedra forming layers, which are held in position by InO6 octahedra acting as pillars forming 12-membered ring channels. The extra-framework sodium cations are located at the sides of the 12-rings within this framework structure and are coordinated by framework oxygen atoms and extra-framework water molecules. The structure was solved using room-temperature single-crystal X-ray diffraction data from 1732 observed reflections (I > 3.0 sigma(I), R = 0.025, and R-w = 0.030).