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A New Oxyborate in the Ternary Phase Diagrams Li

Journal Article · · Journal of Solid State Chemistry
A new type of lithium rare earth oxyborate of formula Li{sub 2}Ln{sub 5}O{sub 4}(BO{sub 3}){sub 3} (Ln=Yb, Lu) has been discovered in the ternary phase diagrams Li{sub 2}O-Ln{sub 2}O{sub 3}-B{sub 2}O{sub 3}: Li{sub 2}Ln{sub 5}O{sub 4}(BO{sub 3}){sub 3}. Single crystals of Li{sub 2}Yb{sub 5}O{sub 4}(BO{sub 3}){sub 3} were grown by the flux method. The structure of this oxyborate was solved from a data collection with a four circle automatic diffractometer and with MoKa radiation. The cell is monoclinic (space group P21/m, Z=2) with a=10.095(2) {angstrom}, b=3.519(2) {angstrom}, c=15.647(11) {angstrom}, b=105.45(3){degree}, V=535.7(5) {angstrom}{sup {minus}3}. Refinement of 86 parameters using 3298 independent reflections having intensity I > 2s(I) led to R=0.037 (wR=0.091). The structure of Li{sub 2}Yb{sub 5}O{sub 4}(BO{sub 3}){sub 3} is made up of a bidimensional framework of edge or corner-sharing YbO{sub 7} polyhedra parallel to the (10-1) plane and connected by three-coordinated boron atoms and lithium ions. It can also be described as a bidimensional assembly of OYb{sub 4} tetrahedra, ((Yb{sub 10}O{sub 8}){sup 14+}){sub n}, separated by borate groups and lithium coordination polyhedra forming ribbons, ((Li{sub 4}B{sub 6}O{sub 18}) Li{sub 2}O-Ln{sub 2}O{sub 3}-B{sub 2}O{sub 3}: Li{sub 2}Ln{sub 5}O{sub 4}(BO{sub 3}){sub 3}({sup 14-}){sub n}), along the b direction. The presence of oxygen atoms sharing only Yb polyhedra justifies the oxyborate label.
Research Organization:
Institut de Chimie de la Matiere Condensee de Bordeaux, Universite Bordeaux I, Pessac (FR)
Sponsoring Organization:
None (US)
OSTI ID:
784337
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 156; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English