SINGLE-CRYSTAL STRUCTURE REFINEMENT AND LUMINESCENCE ANALYSIS OF BETA-NAEUF4

The crystal structure of beta-NaEuF4 has been refined from single-crys tal diffraction data. The obtained results confirm the previous descri ption in the hexagonal P (6) over bar-C-3h(1) space group reported by Burns. Three Eu3+ centres could have been identified analysing the int ense luminescence corresponds to the 2h cationic site (Na+) (half occu pied in the structure) partially substituted by Eu3+. Occurrence of th is third EU3+ Site obscures the features due to the other sites in lum inescence spectra and explains the disagreement already noted between the optical study results and the crystallographic data for NaYF4:Eu3. (C) 1997 Elsevier Science S.A.