Synthesis, structure and luminescence property of two lanthanum phosphite hydrates: La2(H2O)x(HPO3)3 (x=1,2x=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/cC2/c (No. 15); a=20.820(5)Å, b=6.717(2)Å, c=14.123(3)Å, β=101.261(3)°β=101.261(3)°, V=1937.0(8)Å3; Z=8Z=8; 2, triclinic, P  -1 (No. 2); a=8.168(3)Åa=8.168(3)Å, b=8.439(2)Å, c=9.337(3)Åc=9.337(3)Å, α=115.641(3)°α=115.641(3)°, β=98.655(3)°β=98.655(3)°, γ=105.124(3)°γ=105.124(3)°, V=533.87(1)Å3, Z=2Z=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=8,9n=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 340 nm under UV excitation.

Graphical abstractTwo lanthanum phosphites, La2(H2O)(HPO3)3 (1) and La2(H2O)2(HPO3)3 (2), were synthesized by modified hydrothermal methods and their crystal structures showed different arrangements of face-sharing dimers of La coordination polyhedron observed for the first time in rare-earth phosphites. The two Ce+3-doped compounds show intensive broad emission band around 340 nm under UV excitation.Figure optionsDownload full-size imageDownload as PowerPoint slide