Synthesis and complete structural characterization by X-ray diffraction and IR are given for sodium-bismuth polyphosphate NaBi(PO3)(4). This compound is monoclinic P2(1)/n with a structural type 11 and with the following unit-cell dimensions: a = 0.7194(1) nm, b = 1.3097(2) nm, c = 0.9858(2) nm, beta = 90.43(1)degrees, V = 0.9288(3) nm(3), Z = 4 and d(cal) = 3.918. The structure was solved from 3097 independent reflections with R-1 = 0.0211 and WR2 = 0.0527, refined with 164 parameters. The atomic arrangement can be described as a long chain polyphosphate organization, helical ribbons (PO3)(n). The ribbons run along the shortest unit-cell directions with a period of four tetrahedra. Bismuth atoms have an eight-fold coordination while sodium atoms have seven oxygen neighbours. IR spectra at room temperature, was investigated in the frequency range 400-1500cm (1),show clearly some characteristic bands of infinite chain structures of PO4 tetrahedra linked by a bridge oxygen. (C) 2004 Elsevier B.V. All rights reserved.