A new 3-D open-framework Li-rich vanadoborate Li10[V12B18O60H6]·28H2O (1) has been successfully synthesized under hydrothermal conditions. The framework of this compound is constructed by the connection of [V12B18O60H6]10− clusters linked through hydrogen bonds and the charge is compensated by disordered Li+ ions. This compound can undergo a phase transition from the crystalline phase to the glassy phase at 220 °C. Interestingly, after transforming into the glass phase, this material exhibits a high Li+ ionic conductivity of 1.77 × 10−2 S cm−1 at 400 °C and the activation energy of lithium ion transport is 0.48 eV.

Herein, a novel open-framework vanadoborate, (H2en)4H2[V12B18O54(OH)6(H2O)]·11H2O (1, en = ethylenediamine), was hydrothermally synthesized and structurally characterized. The framework was constructed by discrete [V12B18O54(OH)6(H2O)]10− polyanion clusters with H2en2+ as counterions. An extended network of hydrogen bonds among polyanions, cations, and crystal water molecules links the structure in three dimensions. These structural features endow the present vanadoborate with unique proton conduction properties. This material shows a high proton conductivity of 1.87 × 10−4 S cm−1 at 333 K under the condition of 100% relative humidity, and the activation energy was estimated to be 0.38 eV.

•Orthoferrite SmFeO3 shows weak ferromagnetism below 655 K and spin reorientation at 460 K.•Mössbauer spectra, temperature dependent dielectric constant and loss reveal a ferroelectric phase transition at 480 K.•The material's non-centrosymmetric Pna21 structure is likely to be responsible for the ferroelectricy in SmFeO3.The perovskite orthoferrite SmFeO3 was synthesized by the hydrothermal method. The Néel temperature of this material was found to be 655 K by temperature-dependent magnetization measurements. Magnetic field-dependent magnetization of the material at 300 K revealed typical weak ferromagnetic behaviour. Dielectric analysis showed a ferroelectric phase transition at 480 K. The structural and magnetic properties of SmFeO3 were also characterized using Mössbauer spectra, which also confirmed this structural transition. The remanent polarization determined by the positive-up-negative-down (PUND) method was approximately 0.012 μC/cm2 at 173 K. Therefore, the results presented here indicate that SmFeO3 is multiferroic at temperatures above room temperature. Our analysis shows that the material's non-centrosymmetric Pna21 structure is likely to be responsible for the ferroelectricy in SmFeO3 rather than the Pbnm structure or the magnetic structure.

Two new isostructural metal borophosphates, |K2(H2O)|[CoB2P3O12(OH)] [M = Co (1), Ni (2)], have been hydrothermally synthesized with non-polluting K+ ions instead of organic template-ethylenediamine. The two metal borophosphates are isostructural and constructed by the connection of tetrahedral layers and MO6 octahedra, giving rise to the 3-D intersecting 8-ring channels along the [010] direction. The negative charge of the framework is compensated by the K+ ions located in the 8-ring channels. Like ethylenediamine, the K+ ions also play an important structural directing role in the formation of the open framework. The framework shows a high thermal stability and is stable upon calcination at ca. 400 and 500 °C for 1 and 2, respectively. Considering the motion of K+ ions, ionic conductivities of the two compounds were performed. The results indicated that they have similar activation energies of 0.94–1.09 eV and conductivities of 6.76 × 10−8–9.88 × 10−8 S cm−1 at 320 °C.

•It is the first example of 3D supramolecularopen-framework consisting of both inorganic borate polyanion and organic acid anionA borate compound [Ni(en)3][B5O6(OH)4][CH3COO] (1) has been synthesized under mild hydrothermal conditions. The newly synthesized compound was characterized by single-crystal X-ray diffraction, elemental analysis and thermogravimetry. The three-dimensional (3D) supramolecular open-framework of compound 1 is constructed by inorganic [B5O6(OH)4]− building units and organic [CH3COO]− anions through hydrogen bonds, and the charge-balancing [Ni(en)3]2 + cations are located in 3D channels. It is very interesting that there exist two helical chains formed by [B5O6(OH)4]− building units and organic [CH3COO]− anions through hydrogen bonds in compound 1 along different axes. Magnetic measurement indicates that compound 1 exhibits paramagnetic behavior down to 4 K.The inorganic [B5O6(OH)4]− and organic [CH3COO]− anions co-constructed 3D supramolecular open-framework which exist two helical chains through hydrogen bonds in the compound along different axes.

The double perovskite Y2NiMnO6 was prepared by a mild hydrothermal method. The room temperature powder X-ray diffraction analysis shows that it crystallizes in the monoclinic perovskite lattice with space group P21/n. Analysis by bond valence sum and X-ray photoelectron spectroscopy reveal its oxide states to be Ni2+/Mn4+. Magnetic behaviours were characterized by DC and AC magnetic susceptibility, as well as magnetization–hysteresis. After the as-synthesized sample was annealed at 1273 K, the order of the arrangement between Ni2+ and Mn4+ increased. Close to the magnetic ordering temperature, a dielectric anomaly was observed at 84 K. The ferroelectric polarization of about 35 μC m−2 at 77 K was determined by Positive-Up-Negative-Down method, which is induced by up-up-down-down magnetic arrangement as expected theoretically.

A series of pyrochlore oxides, R2Ru2O7 (R = Pr3+, Sm3+-Ho3+) were synthesized under mild hydrothermal conditions. All the samples crystallize in uniform octahedron characteristically. The products were characterized by powder X-ray diffraction, scanning electron microscopy, energy-disperse X-ray spectroscopy, and dc susceptibility, and the factors that affected the crystallization were discussed. It was found that the purity of products depends strongly on the raw materials and the amount of alkalinity in the initial reaction mixtures. The ZFC and FC susceptibilities of all of the compounds R2Ru2O7 at low temperature were also measured and discussed.

Herein, a novel open-framework vanadoborate, (H2en)4H2[V12B18O54(OH)6(H2O)]·11H2O (1, en = ethylenediamine), was hydrothermally synthesized and structurally characterized. The framework was constructed by discrete [V12B18O54(OH)6(H2O)]10− polyanion clusters with H2en2+ as counterions. An extended network of hydrogen bonds among polyanions, cations, and crystal water molecules links the structure in three dimensions. These structural features endow the present vanadoborate with unique proton conduction properties. This material shows a high proton conductivity of 1.87 × 10−4 S cm−1 at 333 K under the condition of 100% relative humidity, and the activation energy was estimated to be 0.38 eV.

Two new isostructural metal borophosphates, |K2(H2O)|[CoB2P3O12(OH)] [M = Co (1), Ni (2)], have been hydrothermally synthesized with non-polluting K+ ions instead of organic template-ethylenediamine. The two metal borophosphates are isostructural and constructed by the connection of tetrahedral layers and MO6 octahedra, giving rise to the 3-D intersecting 8-ring channels along the [010] direction. The negative charge of the framework is compensated by the K+ ions located in the 8-ring channels. Like ethylenediamine, the K+ ions also play an important structural directing role in the formation of the open framework. The framework shows a high thermal stability and is stable upon calcination at ca. 400 and 500 °C for 1 and 2, respectively. Considering the motion of K+ ions, ionic conductivities of the two compounds were performed. The results indicated that they have similar activation energies of 0.94–1.09 eV and conductivities of 6.76 × 10−8–9.88 × 10−8 S cm−1 at 320 °C.

A new 3-D open-framework Li-rich vanadoborate Li10[V12B18O60H6]·28H2O (1) has been successfully synthesized under hydrothermal conditions. The framework of this compound is constructed by the connection of [V12B18O60H6]10− clusters linked through hydrogen bonds and the charge is compensated by disordered Li+ ions. This compound can undergo a phase transition from the crystalline phase to the glassy phase at 220 °C. Interestingly, after transforming into the glass phase, this material exhibits a high Li+ ionic conductivity of 1.77 × 10−2 S cm−1 at 400 °C and the activation energy of lithium ion transport is 0.48 eV.