X-RAY-POWDER STRUCTURE AND RIETVELD REFINEMENT OF THE MONOSODIUM-EXCHANGED MONOHYDRATE OF ALPHA-ZIRCONIUM PHOSPHATE, ZR(NAPO4)(HPO4).H2O Academic Article uri icon

abstract

  • The crystal structure of the partially hydrated monosodium-exchanged phase of a-zirconium phosphate, Zr(HPO4)2H2O, has been determined by using data collected on a conventional computer-controlled X-ray powder diffractometer. The positions of all atoms in the layer were determined by using 40 unambiguously indexed reflections, obtained by pattern decomposition, in a conventional single-crystal type analysis. Whole-pattern (Rietveld) analysis was then conducted to Rwp= 0.156 and resulted in the location and refinement of the exchanged Na+ion and the water oxygen in the interlamellar space. Zr(NaPO4)(HPO4)H2O is monoclinic, P21/c, with cell parameters a = 8.8264 (2) , b = 5.3494 (1) , c = 16.0275 (6) , = 101.857 (4), and Z = 4. The structure is a modification of the parent a-zirconium phosphate with a shift of adjacent layers and twisting of the phosphate groups. This results in an altered cavity arrangement. Na+lies in a distorted octahedral environment, as does the water oxygen, 012. This arrangement of atoms in the interlamellar region is in an ordered manner similar to that in Zr(NH4PO4)2H2O. Loss of the 1 mol of water results in a change in space group, and a mechanism for this transformation as well as that of the exchange process will be described. 1989, American Chemical Society. All rights reserved.

published proceedings

  • INORGANIC CHEMISTRY

author list (cited authors)

  • RUDOLF, P. R., & CLEARFIELD, A.

citation count

  • 44

complete list of authors

  • RUDOLF, PR||CLEARFIELD, A

publication date

  • May 1989