STRUCTURE AND LUMINESCENT PROPERTIES OF Y-17.33(BO3)(4)(B2O5)(2)O-16

Yttrium berate Y-17.33(BO3)(4)(B2O5)(2)O-16, known as Y3BO6 previously , was prepared from stoichiometric starting materials of H3BO(3) and Y 2O3 by a solid-state reaction at high temperatures. Y-17.33 (BO3)(4)(B 2O5)(2)O-16 crystallizes in the monoclinic space group Cm with the lat tice constants a = 1816.62(3), b = 365.16(1), c = 1397.75(3) pm, and b eta = 119.75(2)degrees. The structure of Y-17.33(BO3)(4)(B2O5)(2)O-16 was determined using the direct methods applied to X-ray powder diffra ction data and consists of BO33- and B2O54- borate groups and seven-an d eight-coordinated yttrium atoms. The composition obtained from the s tructure determination corresponds to Y3BO6 with a slight excess of B2 O3. The luminescent properties of the Eu3+ doped Y-17.33(BO3)(4) (B2O5 )(2)O-16 materials were studied and the Eu3+ emission appears as super imposed bands with a high self-quenching concentration. (C) 1997 Acade mic Press.