Structure of a new compound KBaB[sub 5]O[sub 9] and photoluminescence characteristics of KBaB[sub 5]O[sub 9]:Eu[sup 3+]

Crystal structure of a new compound KBaB5O9 has been investigated from X-ray powder diffraction data. This compound is isostructural with KSrB5O9 and crystallizes in the monoclinic system with space group P2(1)/c. Unit-cell parameters are a=6.7200(2) angstrom, b=8.3256(2) angstrom, c=14.3674(4) angstrom, and beta=92.6103(3) deg. Its structure contains both B3O7 and B3O8 rings, which share a common B atom to form a complex two dimensional network constituting the basic B5O9 unit in the formula. Adjacent networks are bound together by Ba and K atoms, which have eight- and nine-coordinate sites, respectively. In addition, DTA and TGA curves reveal that KBaB5O9 decomposes at 798 degrees C. Photoluminescence (PL) characteristics of KBaB5O9:Eu3+ have been studied. The PL spectra show the strongest emission at 618 nm and the quench concentration of Eu3+ is 4 at. %. (C) 2007 International Centre for Diffraction Data.