| Using room temperature slow evaporation method and boric acid flux method,single crystals of K2Ba[B4O5?OH?4]2·10H2O,K2Sr[B4O5?OH?4]2·10H2O and MgB12O24H10 were prepared.Then,the synthesized single crystals were characterized by single-crystal X-ray diffraction,X-ray powder diffraction?XRD?,thermal gravity?TG-DSC?and infrared spectrum?IR?,respectively.1.Using the room temperature slow evaporation method,the single crystal of K2Ba[B4O5?OH?4]2·10H2O was synthesized.The structure of the borate was determined by single-crystal X-ray diffraction.The compound of K2Ba[B4O5?OH?4]2·10H2O is orthorhombic,space group is Pna21 with the unit cell dimensions a=16.7355?11??,b=12.9626?8??,c = 11.5371?7??,? =? =? = 90°,V=2502.8?3??3,Z=4?The molecule contains an eight-coordination Ba atom and two styles of K atoms.One of the K atoms is assigned to seven-coordination and the other is six-coordination.The layer-by-layer arrangement of [B4O5?OH?4]2-clusters links with cations via common oxygen atoms to build three dimensions structure.According to the anions groups theory,the asymmetry of the structure endows with the the nonlinear optical property.The powder NLO text determined that K2Ba[B4O5?OH?4]2·10H2O had 0.5KDP,which showed that it was a potential NLO crystal.2.K2Sr[B4O5?OH?4]2·10H2O belongs to orthorhombic.The space group is Pna21 with the unit cell dimensions a=16.7355?11??,b=12.9626?8??,c = 11.5371?7??,? =? =? = 90°,V=2502.8?3??3,Z=4?The molecule contains two types of K atoms.One is assigned to seven-coordination and the other is six-coordination.The layer-by-layer arrangement of [B4O5?OH?4]2-clusters links with other cluster via common oxygen atoms to build three dimension structure.The asymmetry of the structure endowed with the compound 0.3KDP.3.Using the boric acid flux method,the single crystal of MgB12OH10 was synthesized.The space group is P21/c belonging to orthorhombic,with the following unit cell dimensions a=11.508?5??,b = 8.535?4??,c = 8.628?4??,? =? =? = 90°,V=826.8?6??3,Z=2?The molecule contains a six-coordination Mg2+.The polyborite anions was assembled by BO3 and BO4 groups,which showed a high thermostability.According to the density electron theory?DFT?,the band gap of the compound is 5.691 eV.The corresponding density of state?DOS?and partial density of state?PDOS?of atom belonged to the compound illustrated that the energy levels around the energy gap were constructed with the p orbits of B and O atoms.4.According to solid-liquid-solid phase transition method,Pinnoite was synthesized under the optimum condition of 8 mmol hungtsaoite and 1% boric acid solution at 80°C.The effects of reaction time,pH value and concentrations of magnesium and borate were investigated.The products were determined using X-ray diffraction,Fourier-transform infrared spectroscopy,TG-DSC and a UV-vis spectrometer.The change processes of the surface morphology of pinnoite were investigated using scanning electron microscopy.In addition,the formation mechanism of pinnoite was discussed according to the changes in the content of precipitation and pH value. |
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