Synthesis, structure and luminescence property of two lanthanum phosphite hydrates: La2(H2O)x(HPO3)3 (x=1,2)

Two new lanthanum phosphite hydrates, La2(H2O)(HPO3)3 (1) and La2(H2O)2(HPO3)3 (2), were synthesized by a hydrothermal method. Their crystal structures were determined by X-ray single-crystal method (1, monoclinic, C2/c (No. 15); a=20.820(5)A, b=6.717(2)A, c=14.123(3)A, β=101.261(3)o, V=1937.0(8)A3; Z=8; 2, triclinic, P-1 (No. 2); a=8.168(3)A, b=8.439(2)A, c=9.337(3)A, α=115.641(3)o, β=98.655(3)o, γ=105.124(3)o, V=533.87(1)A3, Z=2). Both crystal structures present three-dimensional open-framework structures containing channels, and 1 adopts intersecting type. In the two structures, the face-sharing dimers of LaOn (n=8,9) were observed. Other characterizations by IR and TG-DSC were also described. Furthermore, both the compounds doped with Ce+3 showed intensive broad emission band around 340nm under UV excitation