Two borate-carbonates Ba4M(CO3)2(BO3)2(M =Ba, Sr) have been successfully synthesized in the open air representing the first examples of borate-carbnate complex.Their structures were determined by single crystal X-ray ...Two borate-carbonates Ba4M(CO3)2(BO3)2(M =Ba, Sr) have been successfully synthesized in the open air representing the first examples of borate-carbnate complex.Their structures were determined by single crystal X-ray diffraction and they both crystallize in same space group, Pnma.Their structures feature a Ba/Sr-based three dimensional framework composed of the BaO8 polyhedra(the SrO8 polyhedra), isolated BO3 and CO3 triangles. Detailed structure analysis shows that the intergrowth of [Ba3(BO3)2]/[Ba2Sr(BO3)2] and [BaCO3] layers favors the formation of these two borate-carbonates. In addition, their syntheses, spectroscopic properties and thermal behaviors were investigated.展开更多
By the combination of the isolated P2O7 dimers and Mg O4 tetrahedra,α-andβ-Rb2Mg3(P2O7)2 polymorphs were synthesized by a high-temperature solution method.α-Rb2Mg3(P2O7)2 crystallizes in non-centrosymmetric space g...By the combination of the isolated P2O7 dimers and Mg O4 tetrahedra,α-andβ-Rb2Mg3(P2O7)2 polymorphs were synthesized by a high-temperature solution method.α-Rb2Mg3(P2O7)2 crystallizes in non-centrosymmetric space group P212121,whileβ-Rb2Mg3(P2O7)2 crystallizes in centrosymmetric P21/c.Both structures contain a three dimensional[Mg3P4O14]^2- anionic framework,while Rb^+ cations are in the space.Structure analyses show that the isolated P2O7 dimers can easily adjust their variable configurations and orientations to fit the different coordination environments of the cations,which is conducive to the formation of polymorphs.The phase transformation process fromα-toβ-Rb2Mg3(P2O7)2 was further investigated by powder X-ray diffraction and thermal gravimetric/differential scanning calorimetry measurements.In addition,UV-vis-NIR diffusion spectra indicate both materials have deep-ultraviolet cut-off edges(below 190 nm).α-Rb2Mg3(P2O7)2 is second-harmonic generation(SHG)-active and the origin of SHG response was investigated by the SHG density calculations.The first-principle calculations were also carried out to illuminate their structure-property relationships.展开更多
Alike phosphates,silicates and germanates exclusively containing tetrahedral basic building units(BBUs)can also exhibit ultraviolet(UV)even deep-UV transitions.They are important for the design of new UV or deep-UV no...Alike phosphates,silicates and germanates exclusively containing tetrahedral basic building units(BBUs)can also exhibit ultraviolet(UV)even deep-UV transitions.They are important for the design of new UV or deep-UV nonlinear optical(NLO)materials.In this paper,four new alkali metal silicates and germanates,Li2Rb4Si6O15,Li2Cs4Si6O15,Li3Rb3Ge6O15 and Li3Cs3Ge6O15 were successfully synthesized by a high temperature solid state reaction.They obey the general formula of LimAnM6O15(A=Rb,Cs;M=Si,Ge;m+n=6)and all exhibit the Sr2Be2B2O7(SBBO)-like structures.More importantly,Li3Rb3Ge6O15 and Li3Cs3Ge6O15 crystallize in the noncentrosymmetric(NCS)structures and exhibit remarkable phase-matched second harmonic generation(SHG)effect,0.8×KH2PO4(KDP)and 1×KDP,respectively.These indicate that they are potential as UV or deep-UV NLO materials.Furthermore,their optical and NLO properties as well as thermal properties were measured.The structure-property relationships were studied by the dipole moment calculations and the first-principles calculations.展开更多
基金supported by the Key Research Project of Frontier Science of CAS (QYZDB-SSW-JSC049)the Western Light Foundation of CAS (2016-QNXZ-A-2)Xinjiang International Science & Technology Cooperation Program (2017E01014)
文摘Two borate-carbonates Ba4M(CO3)2(BO3)2(M =Ba, Sr) have been successfully synthesized in the open air representing the first examples of borate-carbnate complex.Their structures were determined by single crystal X-ray diffraction and they both crystallize in same space group, Pnma.Their structures feature a Ba/Sr-based three dimensional framework composed of the BaO8 polyhedra(the SrO8 polyhedra), isolated BO3 and CO3 triangles. Detailed structure analysis shows that the intergrowth of [Ba3(BO3)2]/[Ba2Sr(BO3)2] and [BaCO3] layers favors the formation of these two borate-carbonates. In addition, their syntheses, spectroscopic properties and thermal behaviors were investigated.
基金financially supported by the National Natural Science Foundation of China (51972230, 51802217, 61835014, 51890864 and 51890865)the Natural Science Foundation of Tianjin (19JCZDJC38200)the National Key Research and Development Project (2016YFB0402103)
文摘By the combination of the isolated P2O7 dimers and Mg O4 tetrahedra,α-andβ-Rb2Mg3(P2O7)2 polymorphs were synthesized by a high-temperature solution method.α-Rb2Mg3(P2O7)2 crystallizes in non-centrosymmetric space group P212121,whileβ-Rb2Mg3(P2O7)2 crystallizes in centrosymmetric P21/c.Both structures contain a three dimensional[Mg3P4O14]^2- anionic framework,while Rb^+ cations are in the space.Structure analyses show that the isolated P2O7 dimers can easily adjust their variable configurations and orientations to fit the different coordination environments of the cations,which is conducive to the formation of polymorphs.The phase transformation process fromα-toβ-Rb2Mg3(P2O7)2 was further investigated by powder X-ray diffraction and thermal gravimetric/differential scanning calorimetry measurements.In addition,UV-vis-NIR diffusion spectra indicate both materials have deep-ultraviolet cut-off edges(below 190 nm).α-Rb2Mg3(P2O7)2 is second-harmonic generation(SHG)-active and the origin of SHG response was investigated by the SHG density calculations.The first-principle calculations were also carried out to illuminate their structure-property relationships.
基金supported by the Natural Science Foundation of Tianjin(19JCZDJC38200)the National Natural Science Foundation of China(51802217,51972230,61835014,51890864 and 51890865)the National Key R&D Program of China(2016YFB0402103)。
文摘Alike phosphates,silicates and germanates exclusively containing tetrahedral basic building units(BBUs)can also exhibit ultraviolet(UV)even deep-UV transitions.They are important for the design of new UV or deep-UV nonlinear optical(NLO)materials.In this paper,four new alkali metal silicates and germanates,Li2Rb4Si6O15,Li2Cs4Si6O15,Li3Rb3Ge6O15 and Li3Cs3Ge6O15 were successfully synthesized by a high temperature solid state reaction.They obey the general formula of LimAnM6O15(A=Rb,Cs;M=Si,Ge;m+n=6)and all exhibit the Sr2Be2B2O7(SBBO)-like structures.More importantly,Li3Rb3Ge6O15 and Li3Cs3Ge6O15 crystallize in the noncentrosymmetric(NCS)structures and exhibit remarkable phase-matched second harmonic generation(SHG)effect,0.8×KH2PO4(KDP)and 1×KDP,respectively.These indicate that they are potential as UV or deep-UV NLO materials.Furthermore,their optical and NLO properties as well as thermal properties were measured.The structure-property relationships were studied by the dipole moment calculations and the first-principles calculations.
