新钽酸盐K6FeTa15O42的合成与表征

在K2O－Fe2O3-Ta2O5三元系统中,新发现存在钽酸盐K6FeTa15O42,使用X射线衍射（XRD)、电子探针微区分析（EPMA）、扫描电镜（SEM）、差热分析（DTA）等方法对该化合物的晶体结构、成分、形态、光学性质、溶解性、熔点及密度进行了研究。新化合物K6FeTsa14O42晶体属于六方晶系,空间群P63／mcm,晶胞参数a=0.91221(1)nm,c=1.21084(4)nm,Z=1,V=0.87258nm^3。     

Crystal growth and structure determination of oxygen-deficient Sr6Co5O15

Large single crystals of oxygen-deficient Sr6Co5O(15-delta) compounds, i.e., Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36, were obtained by using K2CO3 flux in the presence of additives of transition metal oxides. The single-crystal structure determination shows that the structures of Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 crystallize in the space group R and can be described as one-dimensional face-sharing CoO3 polyhedral chains and Sr cation chains. Unlike the other known 2H-perovskite-related oxides in which the polyhedral chains consist of octahedra (Oh) and trigonal prism (TP), the structure of Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 contain Oh and intermediate polyhedra (IP) and can be attributed to a general structure formula A6A'2B3O(15-delta), which is closely related to the known A6A'B4O15 phases by shifting of a B atom and the O3 triangle along the c axis. Further study on O3 reveals that this oxygen position splits into two independent positions, corresponding to polyhedral geometry of IP and TP, respectively. Therefore, the polyhedral chain in the structure should be more precisely described as a random composite of the 4Oh + TP and 3Oh + 2IP. This model is used to interpret the magnetic properties, although not quantitatively. The 4-D structure analysis was also conducted for both Sr6Co5O14.70 and Sr6Co4.9Ni0.1O14.36 with a commensurate modulated structure in a 4-D superspace group, R3m(00gamma)0s, gamma = p/k = 3/5. By considering the same 4-D superspace group R3m(00gamma)0s but different t-phases, one can understand the structure relationship between Sr6Co5O14.70 and Sr6Rh5O15.     

V(IV)15Sb(III)6O42]6-: an antimony analogue of the molecular magnet [V15As6O42(H2O)]6-

A hydrothermal approach employing an amine as reducing agent enables synthesis of an analogue of the arsenato(iii)-oxovanadate {V(15)As(6)}, representing the first systematic variation of this intensely studied magnetic system.     

Crystal structure of the pyrovanadate K4V2O7

The crystal structure of anhydrous K₄V₂O₇ (I) is determined by powder X-ray diffraction. The compound crystallizes in the monoclinic system (a = 10.222(1) Å, b = 6.2309(8) Å, c = 7.282(1) Å, β = 101.31(1)°, space group C2/m, Z = 2). The structure contains layers of isolated V₂O₇ pyrovanadate groups separated by layers of potassium cations. The hydration and dehydration of I are studied by thermal analysis and high-temperature X-ray diffraction. The dehydration is accompanied by decomposition of the starting crystal hydrate to give intermediate compounds. Anhydrous compound I undergoes a reversible phase transition at 740°C. The high-temperature phase is assumed to have a hexagonal unit cell (a = 6.169(4) Å, c = 15.72(1) Å, Z = 2).     

Crystal structure and spectroscopic characterization of K8(VO)2O(SO4)6

Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-sulfato)bis(oxodisulfatovanadate), K(8)(VO)(2)O(SO(4))(6), have been obtained from the ternary catalytic model melt system K(2)S(2)O(7)[bond]K(2)SO(4)[bond]V(2)O(5). By slow cooling of the melt from 420 to 355 degrees C, crystal growth occurred, using solid V(2)O(5) crystals present in the melt as nucleation promoter. The compound crystallizes in the monoclinic space group P2(l) with a = 13.60(9) A, b = 13.93(9) A, c = 14.05(9) A, beta = 90.286(10) degrees, and Z = 2. It contains two VO(6) octahedra linked together by a mu-oxo and two mu-sulfato bridges. Furthermore, each octahedron has two monodentate sulfate ligands, making the dimeric entity coordinatively saturated. IR spectroscopy shows bands arising from V[bond]O[bond]V and V[double bond]O stretches as well as splitting of sulfate bands due to the different degrees of freedom present for different conformations of sulfate ligands. The coordination of vanadium in K(8)(VO)(2)O(SO(4))(6) is discussed in relation to the reaction mechanism of SO(2) oxidation catalysis.     

Crystal structure of [ZnCl·15-crown-5·H2O]2Zn2Cl6

State Scientific-Research Institute of Chemistry and Technology of Organometallic Compounds. L. Ya. Karpov Scientific-Research Physical Chemistry Institute, M. V. Lomonosov Moscow State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 3, pp. 161–164, May–June, 1989.     

ChemInform Abstract: Two Structure Types Based on Si6O15 Rings: Synthesis and Structural and Spectroscopic Characterization of Cs1.86K1.14DySi6O15 and Cs1.6K1.4SmSi6O15.

Single crystals of Cs_1.86K_1.14DySi₆O₁₅ (I) and Cs_1.6K_1.4SmSi₆O₁₅ (II) are grown by reaction of SmF₃ or Dy₂O₃, DyF₃, SiO₂, K₂CO₃, and Cs₂CO₃ in a MoO₃ or MoO₃/RbF flux (Pt crucible, 950 °C, 3—6 h; controlled cooling).     

K4H2[SiW5Mo6Mn(H2O)O39]·22H2O的晶体结构

合成了一个锰硅钼钨四元取代含氧簇合物,用单晶X射线衍射方法测定了结构,该晶体属于四方晶系,空间群P4/mnc,a=14.119(3),c=12.496(4),V=2490.9(12)3,Mr=2862.70,z=2,Dc=3.817g*cm-3,μ=15.922mm-1,R=0.0462,wR=0.1232.锰硅钼钨阴离子中,中心SiO4四面体在C4轴的两个位置上是无序的.     

Crystal structure and chemical thermodynamic properties of potassium d-gluconate K(d-C6H11O7)(s)

Journal of Thermal Analysis and Calorimetry - An important coordination compound potassium d-gluconate K[d-C6H11O7](s) has been synthesized by liquid phase method. The chemical component and...     

K_(10)[H_2W_(12)O_(42)]·11H_2O的合成及晶体结构分析

在水溶液中反应制得无色透明的标题化合物单晶 ,单晶X -射线结构分析表明 ,属单斜晶系 ,空间群P2 1,晶胞参数 :a=1.15 47(2 )nm ,b =1.430 9(3)nm ,c =1.5 495 (3)nm ,β =10 5 .41(3)° ,V =2 .46 81(9)nm3,Z =2 ,Dc=4.6 39Mg/m3,对 5 45 4个独立衍射点 (I>2δ(I) )进行全矩阵最小二乘法修正后 ,可靠性因子R =0 .0 487     

Crystal structure of ZnCl2·H2O·18-crown-6

State Scientific Research Institute for the Chemistry and Technology of Heteroorganic Compounds. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 4, pp. 188–189, July–August, 1989.