title: Flux synthesis, crystal structures, and luminescence properties of salt-inclusion lanthanide silicates: [K9F2][Ln3Si12O32] (Ln = Sm, Eu, Gd).
abstract: New salt-inclusion lanthanide silicates, [K 9F 2][Ln 3Si 12O 32] (Ln = Sm, Eu, Gd), have been synthesized using a KF-MoO 3 flux, and structurally characterized by single-crystal and powder X-ray diffraction. The structures of these three isostructural compounds consist of open-branched funfer silicate single layers with six-, eight-, and twelve-membered rings, which are connected via LnO 6 octahedra to form a 3-D framework. The F (-) and K (+) ions are located in the structural channels and form a F 2K 7 dimer with a structure similar to that of Cl 2O 7. The photoluminescence properties of the Eu compound have also been studied. The sharp peaks in the room-temperature emission spectrum are assigned and the relative intensities of the (5)D 0 --> (7)F 1 and (5)D 0 --> (7)F 2 transitions are consistent with the crystallography results. Crystal data for the Eu compound: triclinic, space group P1 (No. 2), a = 6.8989(2) A, b = 11.3834(4) A, c = 11.4955(4) A, alpha = 87.620(2) degrees , beta = 89.532(2) degrees , gamma = 80.221(2) degrees , and Z = 2. Crystal data for the Sm compound: The same as those for the Eu compound except a = 6.9152(6) A, b = 11.400(1) A, c = 11.531(1) A, alpha = 87.610(1) degrees , beta = 89.445(1) degrees , and gamma = 80.081(1) degrees .
authors.affiliation: Department of Chemistry, National Central University, Jhongli, Taiwan, ROC.
authors.forename: Ming-Feng
authors.initials: MF
authors.lastname: Tang
authors.forename: Pei-Yun
authors.initials: PY
authors.lastname: Chiang
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Su
authors.forename: Yu-Chi
authors.initials: YC
authors.lastname: Jung
authors.forename: Guang-Yi
authors.initials: GY
authors.lastname: Hou
authors.forename: Bor-Chen
authors.initials: BC
authors.lastname: Chang
authors.forename: Kwang-Hwa
authors.initials: KH
authors.lastname: Lii