Rietveld powder structure refinement of Na₂Al₂Ti₆O₁₆; Comparison of synchrotron radiation and conventional x-ray tube datasets

The crystal structure of Na2Al2Ti6O16 was refined by the Rietveld method using synchrotron radiation and conventional x-ray powder data, and the agreement factors were Rp = 3.35%, Rwp = 4.30 %, and RBragg = 6.39% for synchrotron data. The formula based on the chemical analysis and 16 O atoms is Na1.97Al1.82Ti6.15O16. The crystal data are monoclinic, C2/m, a = 12.1239(3) Å, b = 3.7749(1) Å, c = 6.4180(2) Å, β = 107.59(1)°, V = 280.00(4) Å3, Z = 1, and Dx = 3.82 g cm–3. The site occupancy refinement showed a partial ordering of Al3+ and Ti4+ ions in the two-crystallographically independent octahedral sites. © 1990, Materials Research Society. All rights reserved.