(C2N2H10)2Mg(HP2O7)2·2H2O synthesis and crystal structure

(C₂N₂H₁₀)₂Mg(HP₂O₇)₂·2H₂O, is a new inorganic organic hybrid structure. It has been synthetized using wet chemistry. Its crystal structure consists of cis- and trans-edge sharing [MgO₄(H₂O)₂] octahedra resulting in chains, which are linked via [HP₂O₇] units to form [Mg(HP₂O₇)₂(H₂O)₂]⁴⁻ layers. The Mg²⁺ cations and the ethylendiammonium cations are located on centers of inversion. The ethylendiammonium cations are alternately located in the interlayer space. The cohesion of the crystal is well ensured by coulombic interactions between anions and cations and by several hydrogen bonds. The diphosphate anion shows an eclipsed conformation.     

Identification of a new family of diphosphate compounds, AI2BII3(P2O7)2: Structures of Ag2Co3(P2O7)2, Ag2Mn3(P2O7)2, and Na2Cd3(P2O7)2

Syntheses and single-crystal X-ray structural results are reported for three new mixed diphosphates of the family A^I ₂B^II ₃(P₂O₇)₂; Ag₂Co₃(P₂O₇)₂ (I), Ag₂Mn₃(P₂O₇)₂ (II), and Na₂Cd₃(P₂O₇)₂ (III). All crystallize in the triclinic system, space group P1 bar: (I) a = 5.351(4), b = 6.375(4), c = 16.532(4) Å, = 80.83(6) = 81.45(4), = 72.87(5)°, V = 528.9(6) ų, Z = 2, D _calc = 4.649 mg/m³, R/Rw = 0.0428/0.0548 for 3949 obs. reflns; (II) a = 5.432(7), b = 6.619(6), c = 16.51(3) Å, = 80.78(8) = 82.43(9), = 72.82(7)°, V = 557.7(13) ų, Z = 2, D _calc = 4.338 mg/m³, R/Rw = 0.0679/0.1303 for 2100 obs. reflns and (III) a = 5.67(3), b = 7.08(4), c = 7.90(4) Å, = 77.0(2), = 82.5(2), = 67.8(2)°, V = 286(3) ų, Z = 2, D _calc = 4.249 mg/m³, R/Rw = 0.0307/0.0342 for 1945 obs. reflns. (I) and (II) are isostructural but (III) is of a different type. All three structures are characterized by layers of P₂O₇ groups alternating with layers of mixed metal atoms. Differences are seen in the conglomerate bonding patterns of B atoms and in the irregular geometry of Ag in (I) and (II) compared to the octahedral bonding seen for Na in (III). The differences in structure may be understood in terms of the ratios of the ionic radii of A and B atoms.     

Crystal and molecular structure of (2–3-η-2-Butyne-1,4-diol)-bis-(triphenylphosphan)-nickel(O) Ni{[(C6H5)3P]2 (C4H6O2)}

The crystal and molecular structure of (2–3-η-2-Butyne-1,4-diol)-bis-(triphenylphosphan)-nickel(O) has been determined by X-ray structure analysis. It crystallizes in the tetragonal space group 14 with the cell parameters a = b = 22.277(3), and c = 15.118 (4) Å. The structure was solved by the heavy atom method and refined to R = 0.0716. The coordination geometry about the nickel atom is trigonal-planar. Each molecule is hydrogen bonded to two neighbours. The result is an eight-membered oxygen ring.     

Crystal growth and structure determination of the new silicate K3ScSi2O7

Single crystals of the new three-dimensional silicate K₃ScSi₂O₇ were obtained via a high temperature flux method and characterized by single crystal X-ray diffraction. K₃ScSi₂O₇ crystallizes in the space group P6₃/mmc with a = 5.60650(10) Å, c = 13.6420(4) Å. The structure contains sheets of ScO₆ octahedra that are connected via Si₂O₇ bridging groups.     

Optical properties of the germanate melilites Sr2MgGe2O7, Sr2ZnGe2O7 and Ba2ZnGe2O7

Refractive indices and their dispersion in the wavelength range from 365 nm to 2325 nm and transmission ranges of the tetragonal melilite‐type germanates Sr₂MgGe₂O₇, Sr₂ZnGe₂O₇ and Ba₂ZnGe₂O₇ were determined. The uniaxial positive crystals Sr₂MgGe₂O₇ and Ba₂ZnGe₂O₇ both offer the possibility for phase matched second harmonic generation, a detailed analysis of phase matching conditions is given. The refractive indices of Sr₂ZnGe₂O₇ show an isoindex (isotropic) point at 467 nm. The investigation was performed on Czochralski grown large single crystals. The crystal structure of all three germanates were determined by means of X ‐ray diffraction. The results corroborate unmodulated melilite‐type structures at room temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structure of the new barium borate Ba5(BO3)2(B2O5)

The crystal structure of the new barium borate Ba₅(BO₃)₂(B₂O₅) is established (R = 0.0436). Single crystals were grown by spontaneous crystallization in the BaO-B₂O₃-Na₂O system using the flux method. This compound crystallizes in the orthorhombic system, sp. gr. P2₁2₁2₁; the unit-cell parameters are a = 9.590(2) Å, b = 16.659(3) Å, c = 22.919(6) Å, and Z = 12. The structure consists of coordination polyhedra of barium cations and the anionic groups [BO₃] (planar triangles) and [B₂O₅] (vertex-sharing double [BO₃] triangles), which form a pseudohexagonal framework. Melting of barium borate occurs by a peritectic reaction at 1170 ± 10°C.     

混合阴离子磷酸盐RbCd6(P2O7)2P3O10的热学与光学特性研究

利用高温固态反应技术合成了一种新型磷酸盐RbCd6(P2 O7)2 P3O10,并用高温熔盐法自发结晶获得了其单晶.X射线单晶衍射分析表明,该物质结构中含有两种孤立的聚阴离子:P2O7二聚体与P3O10三聚体.两种不同的聚阴离子基元共存于一种结构中,在磷酸盐体系中很少见.这一发现不仅丰富了磷酸盐的结构化学,而且为混合阴离子材料的设计提供了新视角.此外,对该物质的热稳定性及光学性能进行了表征.     

Crystal structure of bis(potassium hydrogenl-malate)·malic acid, 2[K+(C4H5O5)]·C4H6O5

The crystal structure of bis(potassium hydrogenl-malate)·malic acid, 2[K⁺(C₄H₅O₅)^–]·C₄H₆O₅, has been determined: C₁₂H₁₆K₂O₁₅, M _r =1913.9, orthorhombic, space groupP2₁2₁2₁ a=7.719(5),b=7.916(5),c=29.863(20) Å,V _c=1824.7 ų,Z=4. The structure was determined by a new application of theDirdif procedure using MoK automatic diffractometer X-ray data, and refined by full-matrix least squares toR=0.059 for 962 reflections. A question on space-group assignment and composition was resolved only after the structure had been determined. The conformation of the central carbon skeleton of all three crystallographic independent malate moieties isanti. The potassium ions are coordinated by eight oxygen atoms, forming face-sharing distorted square antiprisms.     

Crystal structure, vibrational spectra, and thermal decomposition and nitrogen adsorption behaviour of a new tetramanganese(II) dipyrophosphate decahydrate, Mn4(P2O7)2·10H2O

A new manganese(II) pyrophosphate, Mn₄(P₂O₇)₂·10H₂O, has been synthesized and characterized by single-crystal X-ray diffraction [orthorhombic space group Pnma, with unit cell parameters of a=9.3288(3) ?, b=25.9532(9) ?, c=8.4783(3) ?; Z=4]. All the pyrophosphate anions show non-linear P–O–P bonds with an average angle of 128.60°. The framework of this new pyrophosphate is made up of packed layers of MnO₆ octahedra connected by double-tetrahedra P₂O₇ groups and a layer of Mn(H₂O)₆ units. The [P₂O₇]⁴⁻ anions adopt a bent, near-staggered conformation. The absence of coincidences for the majority of the IR and Raman bands is in accord with the centrosymmetric structure of the material. The vibrational spectra have been interpreted in part on the basis of factor group effects. The structural changes occurring during heating have been investigated by TG-ATD. When Mn₄(P₂O₇)₂ ^.10H₂O is gradually heated, it decomposes into an intermediate hydrated salt at 96°C and then to anhydrous Mn₂P₂O₇ at 325°C. This thermal behaviour is different from that of Zn₄(P₂O₇)₂·10H₂O. The crystal structure of the new managenese(II) pyrophosphate is compared with the known structures of Zn₄(P₂O₇)₂·10H₂O, Mn₂P₂O₇·2H₂O and anhydrous Mn₂P₂O₇. The adsorption and desorption isotherms of Mn₄(P₂O₇)₂·10H₂O, Zn₄(P₂O₇)₂·10H₂O and MnKHP₂O₇·2H₂O have been investigated by BET measurements and the results show that the capacity for N₂ sorption of the Mn(II) salt is two times lower than is that of the Zn(II) isotype and two or three times higher than is that of MnKHP₂O₇·2H₂O.     

Elastic properties of the dithionates Na2S2O6 · 2 H2O,K2S2O6, Rb2S2O6, CaS2O6 · 4H2O and SrS2O6 · 4 H2O

Single crystals of the title compounds having optical quality and dimensions of several cm were grown from aqueous solutions. The elastic and thermoelastic constants were determined from ultrasonic resonance frequencies of thick plates. The true point symmetry of K₂S₂O₆ and Rb₂S₂O₆, which is screened by a hexagonal hypermorphy, could be clearly revealed to be trigonal (32) by the existence of the elastic constant c₁₄. In the case of CaS₂O₆ · 4H₂O and SrS₂O₆ · 4H₂O the constant c₁₄ of the specimens appeared too small to confirm the trigonal symmetry group required from electrooptic and non-linear optic effects unambiguously. The isotypy of K₂S₂O₂ and Rb₂S₂O₆ as well as that of CaS₂O₆ · 4H₂O and SrS₂O₆ · 4H₂O is confirmed by their elastic behaviour. The mean elastic stiffness of dithionates is closely related to that of the corresponding sulphates. In the vicinity of the second-order phase transition of K₂S₂O₆ near 235 K weak anomalies of the temperature derivatives of the longitudinal elastic stiffnesses are observed.     

Crystal growth,crystal structure and pyroelectric properties of the polar hexagonal antimony tartrates MII[Sb2(C4H2O6)2]·2H2O (MII = Ca,Sr, Pb)

Single crystal growth of lead antimony tartrate dihydrate, Pb[Sb₂((+)C₄H₂O₆)₂]·2H₂O, was successfully performed. The determined polar hexagonal crystal structure is isomorphous to the corresponding calcium and strontium antimony tartrates dihydrates. New results of crystal growth and the redetermination of the crystal structures of the nonlinear optical crystal Sr[Sb₂((+)C₄H₂O₆)₂]·2H₂O and its calcium analogue are reported, together with investigations of the thermal stability and the pyroelectric properties of these polar crystals.

     

K2Al2B2O7晶体的热学性质研究

K2Al2B2O7(KABO)晶体是近年发现的一种有应用前景的深紫外非线性光学晶体,也是目前唯一一种可以生长出大尺寸单晶的BO3基团非线性光学晶体.KABO有可能用于固态激光器的266nm及193nm高功率输出.本文对该晶体的物理化学性质及热学性质进行了研究,KABO晶体不潮解,不溶于水、酒精等溶剂,可溶于盐酸,硝酸和磷酸等强酸;测得莫氏硬度为5.5～6.5,用浮力法测得其密度为2.47g/cm3;用差热分析(DTA)方法测量其熔点为1109.7℃.用热重分析(TGA)方法结合分解产物的粉末X射线衍射(XRD)分析,确定KABO在900℃以上开始分解,分解产物主要为KAl11O17和K2Al24O37;用热机械分析仪测量了其热膨胀系数,沿物理学轴X、Y、Z方向分别为8.4×10-6/K、7.7×10-6/K、1.65×10-5/K.在室温至300℃温度范围内测量了KABO晶体的比热变化,比热随温度的升高线性增大.在47.6℃和294.6℃时比热分别为1.0084J/g℃与1.39J/g℃.     

Crystal growth experiments in the systems Ni2MSbO6 (M = Sc,In) using chemical vapour transport reactions: Ni2InSbO6 and NiSb2O6 crystals in the millimetre range

Endothermic chemical vapour transport (CVT) reactions of Ni₂MSbO₆ (M = Sc, In), using a temperature gradient of 1313 → 1233 K and HgCl₂, HgBr₂, PtCl₂ or TeCl₄ as transport agents, led to growth of Ni₂InSbO₆ single crystals in the millimetre range, whereas in the case of Ni₂ScSbO₆ an incongruent dissolution of the solid in the source region was observed, leading to the formation of single crystals of the ternary phase NiSb₂O₆ in the sink region. The crystal structures of the obtained crystals were refined from single crystal X‐ray data with high precision [Ni₂InSbO₆: R3, Z = 3, a = 5.21640(10) Å, c = 14.0142(3) Å, 1279 structure factors, 33 parameters, R[F² > 2σ(F²)] = 0.0189; NiSb₂O₆: P4₂/mnm, Z = 2, a = 4.63910(10) Å, c = 9.2182(2) Å, 500 structure factors, 19 parameters, R[F² > 2σ(F²)] = 0.0145]. Ni₂InSbO₆ crystallizes in a corundum‐related structure, NiSb₂O₆ in the trirutile structure type. Spontaneous polarization and the ferroelectric transition temperature were estimated from the atomic arrangement and cation displacement along the polar axis in Ni₂InSbO₆. Magnetic measurements on Ni₂InSbO₆ evidence an antiferromagnetic transition near T_N = 74 K, with significant magnetic frustration.     

Magnetic and thermodynamic properties and magneto-structural correlation of the diphosphate ZnCoP2O7

ABSTRACT

The structure of the mixed diphosphate ZnCoP₂O₇ is characterized by the cationic order between the diamagnetic and paramagnetic ions. The Co²⁺ ions are lodged in octahedral sites whereas the Zn²⁺ ions occupy distorted square pyramids. The octahedrons CoO₆ share a common edge and form dimers Co₂O₁₀ separated by dimers of zinc, which confers to this compound a low dimensionality character. Magnetic susceptibility shows that ZnCoP₂O₇ is antiferromagnetic. The correlation magneto-structural confirms the presence of Co²⁺ dimers. The magnetic specific heat of ZnCoP₂O₇ shows a large maximum characteristic of a low dimensionality system.     

Syntheses,Characterizations and Crystal Structures of Two New Racemic Amidophosphoesters: rac-(C6H5O)(cyclo-C6H11NH)P(O)N(C4H8)NP(O)(NH-cyclo-C6H11)(OC6H5) and rac-(p-CH3-C6H4NH)P(O)(OC6H4-p-CH3)(OC6H5)

Crystallography Reports - The new racemic compounds, rac-diphenyl bis(cyclo-hexylamido)(piperazine)-1,4-diyldiphosphinate, C28H42N4O4P2 (I), and...     

Crystal and molecular structure of di(μ 3-oxo-tri-μ-oxotrichlorohexakis(pyridine)-triangulotritungsten(IV))hexatungstate(VI)-6-pyridine, [W3(O)O3Cl3(C5H5N)6]2W6O19·6C5H5N

[W₃(O)O₃Cl₃(C₅H₅N)₆]₂W₆O₁₉·6C₅H₅N, the side product of the reaction between WCl₄(C₅H₅N)₂ and pyridine, crystallizes in the rhombohedral space groupR¯3 (No. 148), witha=14.044(1) Å,=87.70(1)°, andZ=1. The structure was solved by the heavy-atom method, and refined to the unweighted and weighted residuals of 0.068 and 0.055, respectively. The tungsten atoms define an equilateral triangle with a capping and three bridging oxygen atoms. Two pyridines in thecis position and a chlorine atom form, together with the oxygens, a distorted octahedron around the tungsten atoms; three octahedra are connected through common edges. Important bond lengths are: W-W (single bond) 2.532(1), W-O (tricapped) 2.09(1), W-O (bridging) 1.92(1) and 1.94(1), W-C1 2.424(5), and W-N (pyridine) 2.23(1) and 2.26(1) Å. In W₆O ₁₉ ^2– , six WO₆ octahedra have one common central oxygen, twelve bridging and six terminal oxygen atoms. Corresponding W-O bond lengths are: 2.323(1) (central oxygen), from 1.90 to 1.94(1) (bridging oxygens), and 1.70(2) Å (terminal oxygens). Lattice pyridine molecules have no important contacts with either anion or cation.     

Hydrothermal crystallization in the KF-ZrO2-SiO2-H2O system at 40°C: Phase equilibria and modeling of ZrSiO4, K2ZrSi6O15, K2ZrSi3O9, K3ZrF7, and ZrO2 crystal structures

The phase equilibria in the KF-ZrO₂ (nanocrystals)-SiO₂-H₂O system are studied for the ZrO₂: SiO₂ molar ratio ranging from 2: 1 to 1: 6 and the KF concentration C _KF ranging from 3 to 36 wt % under 0.1 GPa at 40°C. We established crystallization of three silicates—ZrSiO₄ (zircon), K₂ZrSi₆O₁₅ (deleite), K₂ZrSi₃O₉ (wadeite)—and K₃ZrF₇ fluoride and ZrO₂ and SiO₂ oxides. The structures of K-and Zr-based silicates obtained can be represented as an open framework formed by M octahedra (ZrO₆) that share vertices with T tetrahedra (SiO₄). With the increase of KF concentration, silicates “substitute” each other in the following sequence: ZrSiO₄ ?K₂ZrSi₆O₁₅ ? K₂ZrSi₃ O₉. Depending on the ZrO₂: SiO₂ ratio and C _KF concentration, K₃ZrF₇ fluoride is formed simultaneously with K₂ZrSi₃O₉ and K₂ZrSi₃O₉ + K₂ZrSi₆O₁₅. The characteristic features of formation of Zr-containing phases are discussed in the framework of the model of the matrix assembly of crystal structures from subpolyhedral structural units—clusters of cyclic type. The features of the phase formation in the system are compared with the characteristics determined earlier for the KOH-ZrO₂ (nanocrystals)-SiO₂-H₂O system at 40°C.