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1.
The reactions of the four-coordinated macrocyclic copper complex [CuL](ClO_4)_2(L = 1,4,8,11-tetraazacyclotetradecane) with NH_4VO_3 under different conditions gave three inorganic-organic hybrid materials of [CuL][VO_3]_2·2.33H_2O(1), [CuL]_3[V_(10)O_(28)]·8H_2O(2) and [Cu L]3[V_6O_(18)]·8H_2O(3). Single-crystal X-ray diffraction analyses reveal that three diverse vanadium polyoxoanions, [V_6O_(18)]6- ring, [V_(10)O_(28)]6- cluster, and [V_(12)O_(35)]~(10-) ring, were isolated from the same reactant NH_4VO_3 under different conditions. The [CuL]~(2+) bridges the [V10O28]6- clusters to form a two-dimensional sheet in 2, and link the [V_6O_(18)]~(6-) rings in 1 and [V_(12)O_(35)]~(10-) rings in 3 into three-dimensional frameworks, respectively.  相似文献   

2.
加热温度低于580℃时,V_2O_5/TiO_2催化剂体系内的V_2O_5在TiO_2表面上分散,此时虽有部分V_2O_5碎片渗入TiO_2表层,但还未形成固溶体。在此阶段,随温度的提高,无定形的V=O键伸缩振动(980cm~(-1))先是生成,后逐步消失;V—O—V键的伸缩振动(862cm~(-1))显著减弱,并紫移到885cm~(-1);新出现了1400cm~(-1)吸收峰,它是V_2O_5一级结构及其集合体的表征。同时,在TiO_2的宽频区出现了740,670和594cm(-1)三个吸收峰,这可能是Ti~(4+)d轨道在VO_4影响下能级分裂的结果。580℃到677℃,形成等一类固溶体,上述1400cm~(-1)吸收峰消失,740,670和594cm~(-1)三峰也逐步合一,这是固溶体中V-O-Ti键振动的象征。>677℃,第二类固溶体(V_xTi_(1-x)O_2)出现,其红外光谱同第一类固溶体,但TG有失重。  相似文献   

3.
使用柔性含S有机配体4-(2-噻吩-2-基-乙基)-4H-[1,2,4]三氮唑(L),通过调控反应参数成功制备出4个基于Keggin的化合物,即[Cu~Ⅰ_3L_3(PMo_(12)O_(40))](1)、[Cu~Ⅰ_4L_6(SiW_(12)O_(40))](2)、[Cu_Ⅰ~4L_6(SiMo_(12)O_(40))](3)和[Zn_4L_6(SiW_(12)O_(40))](4),并利用单晶X射线衍射、元素分析和红外光谱进行表征。化合物1中3个Cu+离子聚合3个配体诱导一个环状的三核铜簇。Keggin多阴离子连接三核簇构筑二维层结构。化合物2、3和4同构,包含由6个配体连接4个金属离子(2、3中为铜离子,4中为锌离子)形成的四核[M_4L_6]~(4+)簇。多酸阴离子提供2个氧原子连接2个[M_4L_6]~(4+)簇,从而形成一维链结构。标题化合物对废水中的阳离子染料亚甲基蓝(MB)展示了良好的选择性光催化性能。另外2-CPE(碳糊电极)可作为安培传感器来检测过氧化氢和亚硝酸根。化合物1、2和4展示了对Hg~(2+)的传感性能。  相似文献   

4.
Two new crystals of chlorovanadates,Ba_8Cs_5V_8O_(24)Cl_(13)(1) and MgCsV_2O_6Cl(2),were grown in the molten salt media. 1 crystallizes in tetragonal,space group P4/mmm(No. 123),with a = 14.801(2),c = 12.341(3) ?,V = 2703.5(8) ?~3,Z = 2,Mr = 3015.56,F(000) = 2640,μ = 11.044 mm-1,Dc = 3.704 g/cm3,the final R = 0.0380 and wR = 0.0937 for 1654 observed reflections with I 2σ(I). 2 crystallizes in a monoclinic space group C2/c(No. 15) with a = 11.128(2),b = 10.540(2),c = 6.9892(14) ?,β = 118.38(3)°,V = 721.2(2) ?~3,Z = 4,M_r = 390.55,F(000) = 712,μ = 7.997 mm-1,D_c = 3.597 g/cm~3,the final R = 0.0537 and w R = 0.1363 for 740 observed reflections with I 2σ(I). 1 exhibits a novel 8-membered-ring [V_8O_(24)] consisting of 8 corner-shared VO_4 tetrahetra,but in 2,an infinite ladder-like [VO_3]_∞ chain is formed by VO_5 square pyramids through sharing the edges.  相似文献   

5.
以锐钛矿TiO_2为载体,考察了CeO_2改性对Ag-CeO_2-V_2O_5/TiO_2催化3-甲基吡啶氧化脱甲基性能的影响,并优化了催化剂组成与制备条件.结果表明:Ce掺杂改性不仅能够与V物种作用形成Ce VO_4,而且促进V_2O_5分散,改善活性组分的氧化还原性能,从而提高3-甲基吡啶脱甲基转化率与选择性,改善Ag-V_2O_5/TiO_2催化性能.适宜的催化剂组成为V_2O_5负载量15%,Ce/V的摩尔比0.33,Ag质量分数1.0%.过高的焙烧温度将导致TiO_2载体向金红石型转变,Ag-CeO_2-V_2O_5/TiO_2适宜制备条件为450℃焙烧4 h.  相似文献   

6.
王振庆  王成 《应用化学》2011,28(1):77-82
用水热法合成了含三价砷阴离子AsS3-4的化合物[InAsS4(2,2′-bipy)]2。 该化合物晶体为单斜晶系,空间群为P21/c,晶胞参数a=0.89799(9) nm,b=2.1794(2) nm,c=1.43736(14) nm,β=91.274(2)°,V=2.8123(5) nm3。 在此化合物中用金属螯合物[In(2,2′-bipy)]3+稳定了不常见的三价砷阴离子AsS3-4,讨论了金属价态对最终产物结构的影响,并且研究了该化合物的半导体性质(禁带带宽1.35 eV)。  相似文献   

7.
利用水热合成法得到了有机-无机杂化的钴钼钒簇[Co(en)_2]_4H_4{Co(phen)_2(H_2O)]_2[Mo_9~(VI)V_6~(IV)O_(42)]}[Mo_9~(VI)V_6~(IV)O_(44)]·12H_2O(phen=1,10-邻菲罗啉,en=乙二胺),用元素分析、红外光谱、热分析、磁分析和单晶衍射对该化合物做了表征.该化合物的分子结构单元是由双帽Keggin型多阴离子[Mo_9~(VI)V_6~(IV)O_(42)]~(6-)(简称1)、类似结构的多阴离子[Mo_9~(VI)V_6~(IV)O_(44)]~(10-)(简称2)、过渡金属配合物(两个[Co(phen)_2(H_2O)]~(2+)阳离子和四个[Co(en)_2]~(2+)阳离子)、四个质子和十二个结晶水分子组成.  相似文献   

8.
以NH_4VO_3,Zn(AC)_2和5,5’-mbpy(5,5'-dimethyl-2,2'-bipyridyl)为原料,水热法合成了一个新的钒酸盐化合物[Zn(5,5’-mbpy)(H_2O)V_2O_6]。通过元素分析、红外光谱对其结构进行了表征,利用热重法测定了化合物的稳定性。用X射线单晶衍射法测定了化合物的晶体结构,结果分析表明:晶体属于三斜晶系,P-1空间群,a=0. 8635(9) nm,b=0. 9506(10) nm,c=1. 0781(11) nm,α=93. 817(14)°,β=100. 607(13)°,γ=109. 129(15)°,V=0. 8141(15) nm~3,F_(000)=464,Z=2,R_1=0. 0273,wR_2=0. 0725。该晶体结构的特点是由[V_4O_(12)]~(4-)阴离子簇和[Zn(5,5’-mbpy)(H_2O)]~(2+)阳离子形成的一维链状结构,链与链之间进一步通过分子间弱作用力堆积成三维超分子结构。热重分析表明,化合物晶体结构在温度升至155℃时开始分解,该化合物具有一定的稳定性。  相似文献   

9.
The structure of Na_2H_2[H_2V_2W_(18)O_(62)]12H_2O has been determined by x-rayanalysis.The crystals are trigonal,space group R3m,with cell parametersa=37.613(11),c=12.972(7)A,V=15901(13)A~3,and Z=9.The structure model wasrefined by full-matrix least square to R=0.065 for 1702 reflections with F>4σ(F).The existence of the[H_2V_2W_(18)O_(62)]~(4-)heteropolyanion in the crystals has beenconfirmed.It is composed of two VO_4 tetrahedra and eighteen WO_6 octahedralinked to gve the Dawson-type structure.  相似文献   

10.
本文报道了[KAs_4W_(40)O_(140)(M·H_2O_2]~(n-)杂多阴离子中配位水的取代反应.在水溶液中,许多配体,如[Fe(CN)_6]~(4-)、[Fe(CN)_6]~(3-),SO_3~(2-)等都能取代配位水形成具有特征颜色的配离子.在水溶液中不能发生的配体取代配位水的反应,在非极性有机溶剂中却容易发生,这与配位水分子在非极性有机溶剂中易脱去形成配位不饱和态有关.  相似文献   

11.
K3InF6 is synthesized by a sol-gel route starting from indium and potassium acetates dissolved in isopropanol in the stoichiometry 1:3, with trifluoroacetic acid as fluorinating agent. The crystal structures of the organic precursors were solved by X-ray diffraction methods on single crystals. Three organic compounds were isolated and identified: K2InC10O10H6F9, K3InC12O14H4F18 and K3InC12O12F18. The first one, deficient in potassium in comparison with the initial stoichiometry, is unstable. In its crystal structure, acetate as well as trifluoroacetate anions are coordinated to the indium atom. The two other precursors are obtained, respectively, by quick and slow evaporation of the solution. They correspond to the final organic compounds, which give K3InF6 by decomposition at high temperature. The crystal structure of K3InC12O14H4F18 is characterized by complex anions [In(CF3COO)4(OHx)2](5−2x)− and isolated [CF3COOH2−x](x−1)− molecules with x=2 or 1, surrounded by K+ cations. The crystal structure of K3InC12O12F18 is only constituted by complex anions [In(CF3COO)6]3− and K+ cations. For all these compounds, potassium cations ensure only the electroneutrality of the structure. IR spectra of K2InC10O10H6F9 and K3InC12O12F18 were also performed at room temperature on pulverized crystals.  相似文献   

12.
Two compounds NaSr0.5Al2B2O7 and NaCa0.5Al2B2O7, have been found to crystallize into a new structure type by Rietveld refinement from X-ray powder diffraction data. Their structure belongs to hexagonal space group P63/m, with lattice parameters of , for NaSr0.5Al2B2O7 and , for NaCa0.5Al2B2O7, respectively. The structure is built up by [Al2B2O7]2− double layer and Na+/Ca2+ or Na+/Sr2+ ions alternatively stacking along the c-axis. The sites in the inter-double layer are fully occupied jointly by Na and Ca or Sr, but the intra-double layer sites are only half occupied solely by Na. A mechanism of the transition of the structure from CaAl2B2O7 to present structure type by replacing only 1% Ca by Na (2%) as observed by Chang and Keszler (Mater. Res. Bull. 33 (1998) 299) is also proposed.  相似文献   

13.
New boracites containing nitrato- or fluoroanions that appear to be true low-pressure phases have been synthesized at superatmospheric pressures. The M3B7O13NO3 compounds (M = Co, Ni, Cu, Zn, Cd) transform rapidly and reversibly in the temperature region 300–500°C between probable orthorhombic and face centered cubic symmetry, while the M3B7O13F compounds (M = Mg, Mn, Fe, Co, Zn) appear to maintain rhombohedral symmetry up to their decomposition temperatures of 800–900°C. True high-pressure boracite-like phases containing F and Cr, Mn, Fe, or Co that decompose upon heating to M3B7O13F have also been isolated.  相似文献   

14.
The phase relations in the cross-section of the K2W2O7-K2WO4-KPO3 containing 15 mol% Bi2O3 were undertaken using flux method. Crystallization fields of K6.5Bi2.5W4P6O34, K2Bi(PO4)(WO4), Bi2WO6, KBi(WO4)2 and their cocrystallization areas were identified. Novel phase K6.5Bi2.5W4P6O34 was characterized by single-crystal X-ray diffraction: sp. gr. P−1, a=9.4170(5), b=9.7166(4), c=17.6050(7) Å, α=90.052(5)°, β=103.880(5)° and γ=90.125(5)°. It has a layered structure, which contains {K7Bi5W8P12O68} layers stacked parallel to ab plane and sheets composed by potassium atoms separating these layers. Sandwich-like {K7Bi5W8P12O68} layers are assembled from [W2P2O13] and [BiPO4] building units, and are penetrated by tunnels with K/Bi atoms inside. FTIR-spectra of K2Bi(PO4)(WO4) and K6.5Bi2.5W4P6O34 were discussed on the basis of factor group theory.  相似文献   

15.
Quaternary selenides Sn2Pb5Bi4Se13 and Sn8.65Pb0.35Bi4Se15 were synthesized from the elements in sealed silica tubes; their crystal structures were determined by single-crystal and powder X-ray diffraction. Both compounds crystallize in monoclinic space group C2/m (No.12), with lattice parameters of Sn2Pb5Bi4Se13: a = 14.001(6) Å, b = 4.234(2) Å, c = 23.471(8) Å, V = 1376.2(1) Å3, R1/wR2 = 0.0584/0.1477, and GOF = 1.023; Sn8.65Pb0.35Bi4Se15: a = 13.872(3) Å, b = 4.2021(8) (4) Å, c = 26.855(5) Å, V = 1557.1(5) Å3, R1/wR2 = 0.0506/0.1227, and GOF = 1.425. These compounds exhibit tropochemical cell-twinning of NaCl-type structures with lillianite homologous series L(4, 5) and L(4, 7) for Sn2Pb5Bi4Se13 and Sn8.65Pb0.35Bi4Se15, respectively. Measurements of electrical conductivity indicate that these materials are semiconductors with narrow band gaps; Sn2Pb5Bi4Se13 is n-type, whereas Sn8.65Pb0.35Bi4Se15 is a p-type semiconductor with Seebeck coefficients −80(5) and 178(7) μV/K at 300 K, respectively.  相似文献   

16.
一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…  相似文献   

17.
phase diagrams of KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E 1: 622°C, 8.5 mol % KBO2, 56.5 mol % KCl, and 35 mol % K2CO3; E 2: 710°C, 23 mol % KBO2, 43 mol % K2CO3, and 34 mol % K2MoO4; E 3: 710°C, 23 mol % KBO2, 43 mol % K2CO3, and 34 mol % K2WO4. The specific heats of melting of the eutectics were determined.  相似文献   

18.
The rare earth-platinum-indides Nd6Pt13In22, Sm6Pt12.30In22.70, and Gd6Pt12.48In22.52 were synthesized from the elements by arc-melting of the components. Single crystals were grown using special annealing sequences. The three indides were investigated by X-ray powder and single crystal diffraction: Tb6Pt12In23 type, C2/m, Z=2, a=2811.9(6), b=441.60(9), , β=112.10(3)°, wR2=0.0629, 3645 F2 values, 126 variables for Nd6Pt13In22, a=2821.9(6), b=443.06(9), , β=112.39(3)°, wR2=0.0543, 3679 F2 values, 127 variables for Sm6Pt12.30In22.70, and a=2818.5(6), b=439.90(9), , β=112.29(3)°, wR2=0.0778, 3938 F2 values, 127 variables for Gd6Pt12.48In22.52. Most platinum atoms in these structures have a distorted trigonal prismatic coordination by rare earth metal and indium atoms. Together, the platinum and indium atoms build up a complex three-dimensional [Pt12+xIn23−x] polyanionic network in which the rare earth metal atoms fill distorted pentagonal and hexagonal channels. The 2c Wyckoff site in these structures plays a peculiar role. This site is occupied by indium in the prototype Tb6Pt12In23, while platinum atoms fill the 2c site in Nd6Pt13In22, leading to a linear Pt3 chain with Pt-Pt distances of 275 pm. The crystals with samarium and gadolinium as rare earth metal component show mixed Pt/In occupancies.  相似文献   

19.
马修臻  胡斌 《化学通报》2018,81(10):939-943,938
本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li2SO4 + Na2SO4 + H2O和 Li2SO4 + K2SO4 + H2O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg–1,混合溶液中Na2SO4和K2SO4的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θV和 ψV,模型的计算值与实验值的偏差在±0.002 g.cm3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。  相似文献   

20.
Quaternary chalcogenides InSn2Bi3Se8 and In0.2Sn6Bi1.8Se9 were synthesized on direct combination of their elements in stoichiometric ratios at T>800 °C under vacuum. Their structures were determined with X-ray diffraction of single crystals. InSn2Bi3Se8 crystallizes in monoclinic space group C2/m (No. 12) with a=13.557(3) Å, b=4.1299(8) Å, c=15.252(3) Å, β=115.73(3)°, V=769.3(3) Å3, Z=2, and R1/wR2/GOF=0.0206/0.0497/1.092; In0.2Sn6Bi1.8Se9 crystallizes in orthorhombic space group Cmc21 (No. 36) with a=4.1810(8) Å, b=13.799(3) Å, c=31.953(6) Å, V=1843.4(6) Å3, Z=4, and R1/wR2/GOF=0.0966/0.2327/1.12. InSn2Bi3Se8 and In0.2Sn6Bi1.8Se9 are isostructural with CuBi5S8 and Bi2Pb6S9 phases, respectively. The structures of InSn2Bi3Se8 and In0.2Sn6Bi1.8Se9 feature a three-dimensional framework containing slabs of NaCl-(311) type with varied thicknesses. Calculations of the electronic structure and measurements of electrical conductivity indicate that these materials are semiconductors with narrow band gaps. Both compounds show n-type semiconducting properties with Seebeck coefficients −270 and −230 μV/K at 300 K for InSn2Bi3Se8 and In0.2Sn6Bi1.8Se9, respectively.  相似文献   

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