Abstract
The new niobium phosphates Ba3(NbO)2(PO4)4 (1) and Co3(NbO)2(PO4)4(H2O)10 (2) have been synthesized in single crystal form by hydrothermal reactions at 250 °C and 170 °C respectively. The crystal structures have been determined from X-ray diffraction data. Both compounds contain NbP2O9 complex chains as a fundamental structural unit. The chains are similar to those of the known compound K3NbP2O9 and structurally may be considered similar to a slice of the Zr(HPO4)2 layer in α-zirconium phosphate. In compound 1 the chains are separated and are held together by Ba–O bonds while in 2 the chains are linked by CoO6 octahedra to form a framework structure.