采用原位溶剂热法合成了2种混合有机阳离子杂化甲酸盐(CH(NH_(2))_(2))[RE(HCOO)_(4)](RE=Y、Er)。这2种材料是同构的(手性空间群C222_(1)),并具有有趣的类钙钛矿结构。进行了包括线性和非线性光学特性在内的光物理研究。(CH(NH_(2))_(2...采用原位溶剂热法合成了2种混合有机阳离子杂化甲酸盐(CH(NH_(2))_(2))[RE(HCOO)_(4)](RE=Y、Er)。这2种材料是同构的(手性空间群C222_(1)),并具有有趣的类钙钛矿结构。进行了包括线性和非线性光学特性在内的光物理研究。(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]分别表现出5.59和5.61 e V的宽光学带隙,对应于222和221 nm的紫外吸收边缘。粉末倍频测量表明,(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的倍频效应分别是基准KH_(2)PO_(4)(KDP)的0.32和0.37倍。测量得到(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的双折射率分别为0.013和0.015。第一性原理研究表明,2个π共轭的(CH(NH_(2))_(2))^(+)和HCOO^(-)基团是光学性质的主要贡献者。展开更多
A new tantalate compound KSr 2Ta 3O 10 was synthesized by solid state reaction for the first time in the ternary system K 2O SrO Ta 2O 5, and its single crystals were prepared using flux method. The chemical compositi...A new tantalate compound KSr 2Ta 3O 10 was synthesized by solid state reaction for the first time in the ternary system K 2O SrO Ta 2O 5, and its single crystals were prepared using flux method. The chemical compositions, crystal structure, optical property, density and melting point of the new compound were characterized by EPMA, XRD, DTA and so on. KSr 2Ta 3O 10 crystallizes the orthorhombic system with unit cell parameters a= 0.784 4(1) nm, b =0.777 0(1) nm, c =3.012 7(1) nm and space group P 2 12 12 1, Z =8. The structure may be described as treble perovskite sheets [Sr 2Ta 3O 10 ] - interleaved with K +. Further, it was found that KSr 2Ta 3O 10 has intercalation phenomenon. Na +, Li +, H +, NH + 4 could exchange the interlayer cations K + of KSr 2Ta 3O 10 , and n hexylamine also could intercalate into the place between the layers of [Sr 2Ta 3O 10 ] -. [WT5HZ]展开更多
A New Niobate Ba 5LaTi 2Nb 3O 18 was synthesized by a high temperature solid state reaction in the BaO-La 2O 3-TiO 2-Nb 2O 5 system. The chemical compositions, crystal structure, microstructure, density and melting po...A New Niobate Ba 5LaTi 2Nb 3O 18 was synthesized by a high temperature solid state reaction in the BaO-La 2O 3-TiO 2-Nb 2O 5 system. The chemical compositions, crystal structure, microstructure, density and melting point of the new compound were characterized by EPMA, XRD, SEM, DTA and so on. Ba 5LaTi 2Nb 3O 18 crystallizes the rhombohedral system with unit cell parameters a=0 573 25(2) nm, c=4 213 9(2) nm, and space group R3m, Z=3. The structure may be described as five (Nb,Ti)O 6 octahedra corner-sharing along c axis to form perovskite layer connected by Ba atoms. The Ba 5LaTi 2Nb 3O 18 ceramic exhibits a high dielectric constant of 80.5, low dielectric loss of 6.5×10 -4 and small temperature coefficient of dielectric constant of -78×10 -6 K -1 at 1 MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+, La 3+, Ti 4+ and Nb 5+. Ba 5LaTi 2Nb 3O 18 might be a suitable candidate of high ε r microwave dielectric ceramics.展开更多
A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melti...A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melting point of the new compound were characterized by EPMA,XRD,DTA and so on.Ba 6 LaTi 3 Nb 3 O 21 crystallizes the rhombohedral system with unit cell parameters a=0.57388(2)nm,c=4.9283(3)nm,and space group R3m,Z=3.The structure may be described as six(Nb,Ti)O 6 octahedra corner - sharing along c - axis to form perovskite layer connected by Ba atoms.The Ba 6 LaTi 3 Nb 3 O 21 ceramics exhibits high dielectric of74.1,low dielectric loss of4.7 × 10 -4 and small temperature coefficient of dielectric constant of-69ppm · K -1 at1MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+ ,La 3+ ,Ti 4+ and Nb 5+ .Ba 6 LaTi 3 Nb 3 O 21 might be a suitable candidate of highε r mi - crowave dielectric ceramics.展开更多
A new niobate compound Ba4LaTiNb3O15 has been synthesized and characterized. Through Rietveld refinement of X-ray powder diffraction data, Ba4LaTiNb3O15 is identified as the A5B4O15 type cation-deficient perovskites w...A new niobate compound Ba4LaTiNb3O15 has been synthesized and characterized. Through Rietveld refinement of X-ray powder diffraction data, Ba4LaTiNb3O15 is identified as the A5B4O15 type cation-deficient perovskites with space group of P3m1(164) and lattice constants a=0.572 38(1) nm, c=1.169 48(1) nm, V=0.331 81(1) nm3, and Z=1. The crystal structure can be described as consisting of identical perovskite-like blocks, four corner-sharing (Ba,La)O6 octahedra thick, separated by layers of vacant octahedral. The (Ba,La)-O bond lengths range from 0.267 to 0.321 nm and the (Ti,Nb)-O bond lengths range from 0.175 to 0.213 nm. The Ba4LaTiNb3O15 ceramic has a high dielectric constant of 53.3, high quality factors (Q) 3 650 (at 6.402 5 GHz), and low temperature variation of resonant frequency (τf) +69.3 × 10-6 K-1.展开更多
文摘采用原位溶剂热法合成了2种混合有机阳离子杂化甲酸盐(CH(NH_(2))_(2))[RE(HCOO)_(4)](RE=Y、Er)。这2种材料是同构的(手性空间群C222_(1)),并具有有趣的类钙钛矿结构。进行了包括线性和非线性光学特性在内的光物理研究。(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]分别表现出5.59和5.61 e V的宽光学带隙,对应于222和221 nm的紫外吸收边缘。粉末倍频测量表明,(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的倍频效应分别是基准KH_(2)PO_(4)(KDP)的0.32和0.37倍。测量得到(CH(NH_(2))_(2))[Y(HCOO)_(4)]和(CH(NH_(2))_(2))[Er(HCOO)_(4)]的双折射率分别为0.013和0.015。第一性原理研究表明,2个π共轭的(CH(NH_(2))_(2))^(+)和HCOO^(-)基团是光学性质的主要贡献者。
文摘A new tantalate compound KSr 2Ta 3O 10 was synthesized by solid state reaction for the first time in the ternary system K 2O SrO Ta 2O 5, and its single crystals were prepared using flux method. The chemical compositions, crystal structure, optical property, density and melting point of the new compound were characterized by EPMA, XRD, DTA and so on. KSr 2Ta 3O 10 crystallizes the orthorhombic system with unit cell parameters a= 0.784 4(1) nm, b =0.777 0(1) nm, c =3.012 7(1) nm and space group P 2 12 12 1, Z =8. The structure may be described as treble perovskite sheets [Sr 2Ta 3O 10 ] - interleaved with K +. Further, it was found that KSr 2Ta 3O 10 has intercalation phenomenon. Na +, Li +, H +, NH + 4 could exchange the interlayer cations K + of KSr 2Ta 3O 10 , and n hexylamine also could intercalate into the place between the layers of [Sr 2Ta 3O 10 ] -. [WT5HZ]
文摘A New Niobate Ba 5LaTi 2Nb 3O 18 was synthesized by a high temperature solid state reaction in the BaO-La 2O 3-TiO 2-Nb 2O 5 system. The chemical compositions, crystal structure, microstructure, density and melting point of the new compound were characterized by EPMA, XRD, SEM, DTA and so on. Ba 5LaTi 2Nb 3O 18 crystallizes the rhombohedral system with unit cell parameters a=0 573 25(2) nm, c=4 213 9(2) nm, and space group R3m, Z=3. The structure may be described as five (Nb,Ti)O 6 octahedra corner-sharing along c axis to form perovskite layer connected by Ba atoms. The Ba 5LaTi 2Nb 3O 18 ceramic exhibits a high dielectric constant of 80.5, low dielectric loss of 6.5×10 -4 and small temperature coefficient of dielectric constant of -78×10 -6 K -1 at 1 MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+, La 3+, Ti 4+ and Nb 5+. Ba 5LaTi 2Nb 3O 18 might be a suitable candidate of high ε r microwave dielectric ceramics.
文摘A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melting point of the new compound were characterized by EPMA,XRD,DTA and so on.Ba 6 LaTi 3 Nb 3 O 21 crystallizes the rhombohedral system with unit cell parameters a=0.57388(2)nm,c=4.9283(3)nm,and space group R3m,Z=3.The structure may be described as six(Nb,Ti)O 6 octahedra corner - sharing along c - axis to form perovskite layer connected by Ba atoms.The Ba 6 LaTi 3 Nb 3 O 21 ceramics exhibits high dielectric of74.1,low dielectric loss of4.7 × 10 -4 and small temperature coefficient of dielectric constant of-69ppm · K -1 at1MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+ ,La 3+ ,Ti 4+ and Nb 5+ .Ba 6 LaTi 3 Nb 3 O 21 might be a suitable candidate of highε r mi - crowave dielectric ceramics.
文摘A new niobate compound Ba4LaTiNb3O15 has been synthesized and characterized. Through Rietveld refinement of X-ray powder diffraction data, Ba4LaTiNb3O15 is identified as the A5B4O15 type cation-deficient perovskites with space group of P3m1(164) and lattice constants a=0.572 38(1) nm, c=1.169 48(1) nm, V=0.331 81(1) nm3, and Z=1. The crystal structure can be described as consisting of identical perovskite-like blocks, four corner-sharing (Ba,La)O6 octahedra thick, separated by layers of vacant octahedral. The (Ba,La)-O bond lengths range from 0.267 to 0.321 nm and the (Ti,Nb)-O bond lengths range from 0.175 to 0.213 nm. The Ba4LaTiNb3O15 ceramic has a high dielectric constant of 53.3, high quality factors (Q) 3 650 (at 6.402 5 GHz), and low temperature variation of resonant frequency (τf) +69.3 × 10-6 K-1.
