The structure and luminescent properties of Mn05Zr2(PO4)(3)

The phosphate Mn0.5Zr2(PO4)(3) can be obtained at high temperature (1400 de grees C). It crystallizes in the rhombohedral system (space group R (3) ove r bar) with parameters a(h) = 8.85(1) and c(h) = 21.80(5) Angstrom in the e quivalent hexagonal cell. Its structure, determined by the Rietveld method, is typical of the Nasicon-type arrangement with a partial occupation of th e two M(1) sites [(3a) and (3b)] generated by the space group. The magnetic and luminescent properties are consistent with the crystallographic data a nd give evidence of the existence of a small amount of Mn3+ in such as-prep ared samples, the actual composition being Mn2+ Mn-0.5-x(3+) Zr-2x/3(2)(PO4 )(3) With x congruent to 0.03. (C) 2000 Elsevier Science Ltd. All rights re served.