X-RAY-POWDER STRUCTURE OF SR2CEO4 - A NEW LUMINESCENT MATERIAL DISCOVERED BY COMBINATORIAL CHEMISTRY

A new luminescent inorganic oxide with the composition Sr2CeO4 has bee n discovered using combinatorial chemical methodologies. A combinatori al library consisting of more than 25 000 chemically distinct composit ions was prepared by an automated thin film physical vapor deposition method. The lead compound responsible for the luminescence in the Sr-C e-O region of the library was prepared in bulk quantity for structural investigation. The three-dimensional structure of the compound was so lved ab initio from X-ray powder diffraction data and refined by the R ietveld method. The structure consists of one-dimensional chains of ed ge-sharing CeO6 octahedra that are linked together by Sr2+ ions. A bul k sample prepared with the same elemental composition as above but hea ted for a shorter time was analyzed for the presence and amount of dif ferent phases formed in the initial stages of the reaction. The result s show that this sample consists of SrCO3, CeO2, SrCeO3, and Sr2CeO4. Upon prolonged heating the former three phases convert to the final pr oduct, Sr2CeO4. (C) 1998 Elsevier Science B.V. All rights reserved.