A new Rubidium - Bismuth polyphosphate RbBi(PO3)4: Growth, X-ray single crystal and vibrational study

Abstract

Solid-solution studies in the ternary Rb2O – Bi2O3 – P2O5 system, carried out in a search for inorganic materials have a considerable interest mainly for their optical properties, specifically in laser technology, yielded the new compound RbBi(PO3)4. Single-crystal X-ray measurement revealed that RbBi(PO3)4 crystallizes in space group P21/c with a structural type IV and has lattice parameters a = 10.430, b = 8.984, c = 12.967 Ã…, ï¢ = 126.1°, Z = 4 and V = 981.6 Ã…3. The all eighteen atoms were located in the asymmetric unit. Refinement using anisotropic temperature factors for all atoms yielded weighted residuals based on F and F2 values, respectively, of R1 = 0.0131 and WR2 = 0.0252 for all observed reflections. The atomic arrangement can be described as a long chain polyphosphate organization, helical ribbons (PO3)n. Two types of infinite chains, with a period of eight PO4 tetrahedra run along the longest unit-cell directions. Infrared and Raman spectra at room temperature, were investigated, show clearly some characteristics bands of infinite chains structure of PO4 tetrahedra linked by a bridge oxygen.