The single phase compound Na 3SbO(PO 4) 2 was prepared by a solid state reaction. It crystallizes in the orthorhombic system, space group P2 12 12 1 with a = 6.964(1) Å, b = 9.284(2) Å, c = 12.425(2) Å, Z = 4. The structure was determined from 968 reflections collected on a Nonius CAD4 automatic diffractometer with Mo Kα radiation. The final R index and weighted Rw index are 0.031 and 0.039, respectively. The structure is built up from strings of corner-sharing SbO 6 octahedra to which phosphate groups are linked by two of their vertices. These chains, running parallel to the a-axis, are separated from each other by sodium atoms.