Synthesis and crystal structure of sodium-bismuth polyphosphate NaBi(PO3)4

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 400-1500 cm-1, show clearly some characteristic bands of infinite chain structures of PO4 tetrahedra linked by a bridge oxygen.