- First evidence of a phase transition in a high-pressure metal iodate: Structural and thermal studies of AgIO3 polymorphs
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A new phase of silver iodate, β-AgIO3, was obtained at 2.7 GPa by heating the α-AgIO3 precursor above 240 °C. β-AgIO3 is the first iodate obtained at high pressure that stabilizes under normal conditions. The crystal structure was determined by X-ray powder diffraction and Rietveld refinement. In comparison to α-AgIO3, which crystallizes in the Pbc21 acentric orthorhombic space group with the lattice parameters a = 7.265(2) A, b = 15.17(4) A, c = 5.786(2) A, and V = 638(2) A3, β-AgIO3 crystallizes in the Pbca centric orthorhombic space group, with the following parameters: a = 6.137(2) A, b = 16.980(4) A, c = 5.827(1) A, and V = 607.3(3) A3. Differential thermal analysis under high pressure (2.7 GPa) and structural studies showed an endothermic transformation at 260°C corresponding to a first-order reconstructive phase transition from α-AgIO3 to β-AgIO3. The thermal behaviors of α-AgIO3 and β-AgIO3 were studied by differential scanning calorimetry at ambient pressure and in situ temperature-dependent X-ray powder diffraction. Copyright
- Suffren, Yan,Gautier-Luneau, Isabelle,Darie, Celine,Goujon, Celine,Legendre, Murielle,Leynaud, Olivier
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- Hierarchical self-assembly of graphene-bridged on AgIO3/BiVO4: An efficient heterogeneous photocatalyst with enhanced photodegradation of organic pollutant under visible light
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A series of hierarchical AgIO3/BiVO4-GO photocatalysts was synthesized using a solvothermal-precipitation method. The composition, structure, morphology, optical and photoelectrochemical performance of as-obtained photocatalysts were systematically characterized by XPS, XRD, TEM, SEM, EDS, PL, UV–Vis DRS, PT, and EIS, respectively. The photocatalytic activity was evaluated by the degradation of tetracycline hydrochloride (TC) and Rhodamine B (RhB) under visible light irradiation. Experimental results exhibited the photocatalytic degradation activity of AgIO3/BiVO4 was significantly improved compared with pure AgIO3 and BiVO4. This may be due to the heterojunction formation of AgIO3 and BiVO4 and the introduction of GO, which accelerates the separation and migration of electron-hole pairs and reduce recombination. The h+ and ?O2? was the key active species in the photocatalytic degradation process according to the trapping experiment. Furthermore, a potential photocatalytic mechanism was predicted based on experimental results.
- Si, Yushan,Chen, Yongyang,Fu, Yiwen,Zhang, Xinyu,Zuo, Fenfang,Zhang, Tongtong,Yan, Qishe
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- Syntheses and crystal structures of four new silver(I) iodates with d 0-transition metal cations
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Systematic explorations of new phases in the AgI-Ti IV/VV/MoVI-iodate systems led to four new quaternary silver iodates, namely, Ag2Ti(IO3)6, Ag2(VO2)(IO3)3, Ag 2(V2O4)(IO3)4, and Ag2(MoO2)(IO3)4. They represent the first examples of silver iodates containing d0 transition metal cations. Ag2Ti(IO3)6 is isostructural with K2Ti(IO3)6 and its structure features a zero-dimensional (0D) [Ti(IO3)6]2- anionic unit composed of non-distorted TiO6 octahedron corner-sharing with six IO3- groups. Such anions are further bridged by Ag + ions into a 3D network. In both Ag2(VO 2)(IO3)3 and Ag2(V2O 4)(IO3)4, each vanadium(v) is octahedrally coordinated by one terminal and two bridging oxo anions as well as three iodate anions in unidentate fashion. Neighboring VO6 octahedra form a 1D vanadium(v) oxide chain via corner-sharing oxo anions, such chains are further decorated by iodate anions in bridging or unidentate fashion. Ag 2(VO2)(IO3)3 features a thick triple layer composed of two Ag(2)(VO2)(IO3)2 and one Ag(1)IO3 sheet whereas Ag2(V2O 4)(IO3)4 features a 3D network composed of 1D [(V2O4)(IO3)3]- anionic chains along the c-axis that are interconnected by [Ag4(IO 3)2]2+ clusters. Ag2(MoO 2)(IO3)4 is isostructural with K 2(MoO2)(IO3)4 and its structure features a 3D network built from 0D [(MoO2)(IO3) 4]2- anions further interconnected by Ag+ ions. Optical and luminescent property measurements as well as band structure calculations based on density functional theory (DFT) methods have also been performed. The Royal Society of Chemistry 2010.
- Sun, Chuan-Fu,Hu, Chun-Li,Kong, Fang,Yang, Bing-Ping,Mao, Jiang-Gao
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- Second-sphere coordination complexes via hydrogen bonding: Synthesis, characterization of [Co(NH3)6](XO3)3·nH2O (X=Br, I) and single crystal X-ray structure determination of [Co(NH3)6<
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Single crystals of [Co(NH3)6](BrO3)3·0.5H2O and peach coloured precipitate of [Co(NH3)6](IO3)3·3H2O were obtained by reacting hexaamminecobalt(II
- Sharma, Raj Pal,Bala, Ritu,Sharma, Rajni,Perez, Julio,Miguel, Daniel
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- Preferential Solvation of Ag(I) Bromate and Iodate in Dimethyl Sulfoxide-Water Mixtures
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The selective solvation of Ag(I) bromate and iodate was studied in dimethyl sulfoxide-water mixtures at 30 deg C by solubility and EMF measurements.The solubility of silver bromate decreases down to XDMSO=0.2 and thereafter increases with addition of dimethyl sulfoxide, the solubility of silver iodate continuously decreasing under the same conditions.The transfer free energy of silver cation decreases while that of halate ions increases with the addition of dimethyl sulfoxide.The solvent transport number, Δ, passes through a maximum around XDMSO=0.5 in both cases.These results were interpreted in terms of a heteroselective solvation of both the salts, the silver ion being preferentially solvated by dimethyl sulfoxide and the halate ions selectively hydrated by water in the mixtures.
- Janardhanan, Sivasankaran nair,Kalidas, Chatty
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p. 2363 - 2365
(2007/10/02)
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