ChemInform Abstract: A Series of New Silver Selenites with d0-TM Cations

Systematic explorations of new phases in the Ag+–Ti4+/Zr4+/Nb5+/Ta5+–Se4+–O(F) system by hydrothermal syntheses or standard high temperature solid-state reactions resulted in four new mixed-metal silver selenites, namely, Ag3Ti3O3(SeO3)4F (1, P63), Ag2ZrF2(SeO3)2 (2, Cmca) and AgMO(SeO3)2 (M = Nb, 3; Ta, 4) in the space group Cmcm. Ag3Ti3O3(SeO3)4F features an interesting [Ti3O3(SeO3)4]2− 3D anionic framework composed of 1D chains of corner-sharing TiO6 octahedra which are further interconnected by tridentate bridging SeO32− anions, displaying 1D hexagonal channels of Ti6Se6 12-member rings (MRs) along the c-axis, filled by the Ag+ cations and isolated F− anions. More interestingly, it displays a moderate strong Second-Harmonic Generation (SHG) response about 2 times that of KH2PO4 (KDP). Compound 2 features a novel 1D [ZrF2(SeO3)2]2− anionic chain composed of edge-sharing ZrO4F4 polyhedra in which two neighboring Zr4+ cations are further bridged by a pair of selenite anions. Compounds 3 and 4 are isostructural and their structures feature 1D anionic chains of [MO(SeO3)2]− (M = Nb, Ta) which are separated by Ag+ cations, the 1D [MO(SeO3)2]− (M = Nb, Ta) chain is formed by 1D chains of corner-sharing MO6 (M = Nb, Ta) octahedra in which two neighboring metal centers are also bridged by a pair of selenite anions. Other characterizations including thermal analyses, optical and luminescence property measurements have also been performed.