Zum System Zn/Mo/O. I. Phasenbestand und Eigenschaften der ternären Zinkmolybdate; Struktur von Zn3Mo2O9

On the System Zn/Mo/O. I. Phases and Properties of Ternary Zinc Molybdates; Crystal Structure of Zn₃Mo₂O₉ Several ternary compounds are known in the Zn/Mo/O-system. The phases ZnMoO₄, Zn₂Mo₃O₈ and Zn₃Mo₂O₉ are stable at 900°C. The coexistence ranges are shown in the ternary phase diagram. The structure of Zn₃Mo₂O₉ has been determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/m (a = 7,757(1) Å, b = 7,132(1) Å, c = 8,370(2) Å, β = 117,40(1)º, Z = 2).     

Zur Kenntnis von Ba(MgZn)V2O8, BaMn2V2O8 und Ba1/2Sr1/2Ni2V2O8

On Ba(MgZn)V₂O₈, BaMn₂V₂O₈, and Ba_1/2Sr_1/2Ni₂V₂O₈ Ba(Mg, Zn)V₂O₈ (A), BaMn₂V₂O₈ (B) and Ba_1/2Sr_1/2Ni₂V₂O₈ (C) were prepared by solid state reactions (A and B) and crystallization from a melt (C) respectively. (A? C) crystallize in the space group: D-I4₁/acd, Nr. 142. [Lattice constants (A): a = 12.4524(57) Å, c = 8.4408(36) Å; (B): a = 12.5563(14) Å, c = 8.5942(9) Å; (C): a = 12.2248(20) Å, c = 8.3245(15) Å]. (A), (B) and (C) are isotypic to SrNi₂V₂O₈ but showing higher symmetry.     

Zur Koordination des Aluminiums in den Calciumaluminathydraten 2 CaO · Al2O3 · 8 H2O und CaO · Al2O3 · 10 H2O

On the Coordination of Al in the Calcium Aluminate Hydrates 2 CaO · Al₂O₃ · 8 H₂O and CaO · Al₂O₃ · 10 H₂O By investigations with high-resolution ²⁷Al-NMR in solids it is shown that in the compound 2 CaO · Al₂O₃ · 8 H₂O the Al merely exist in octahedral coordination. According to this and considering its structural relationship with 4 CaO · Al₂O₃ · 19 H₂O the dicalcium aluminate hydrate is proposed to be formulated as [Ca₂Al(OH)₆][Al(OH)₃ (H₂O)₃]OH. Likewise for the compound CaO · Al₂O₃ · 10 H₂O the octahedral coordination of the Al is proved by ²⁷Al-NMR. This result corresponds with literature according to which a constitution as cyclohexaaluminate Ca₃[Al₆(OH)₂₄] · 18 H₂O is proposed.     

Phase relations in the system ZnV2O6 -ZnFe2O4

Using DTA and XRD methods, a diagram of phase equilibria in ZnV₂O₆-ZnFe₂O₄ system has been constructed. System ZnV₂O₆-ZnFe₂O₄ is in subsolidus area a real binary system and its components form a compound Zn₂FeV₃O₁₁. Zn₂FeV₃O₁₁ melts incongruently at 835±5°C with deposition of two solid phases: b-Zn₂V₂O₇ and ZnFe₂O₄. This revised version was published online in July 2006 with corrections to the Cover Date.     

一个新颖的由Zn配合物修饰的Keggin型钴钨酸盐：[Zn(2,2’-bipy)3]3{[Zn(2,2’-bipy)2(H2O)]2 [HCoW12O40] 2 }.H2O

通过水热合成技术,一个新颖的基于Zn配合物修饰的Keggin型钴钨酸的有机-无机杂化化合物：[Zn(2,2’-bipy)3]3{[Zn(2,2’-bipy)2(H2O)]2 [HCoW12O40] 2 }.H2O已经被合成,化合物通过红外光谱、热重分析和单晶X-射线衍射进行了表征。单晶X-射线衍射的结果显示标题化合物是由一个单支撑的{[Zn(2,2’-bipy)2(H2O)]2 [HCoW12O40] 2}6-多阴离子,三个[Zn(2,2’-bipy)3]2+阳离子和一个水分子构成。有趣的是[Zn(1)(2,2’-bipy)3]2+阳离子通过氢键连接在一起形成螺旋链。另外标题化合物在空气中是稳定的,并且在室温下显示了强的荧光。     

Subsolidus phase equilibria in the SrO-Bi2O3-B2O3 system

Phase equilibria in the SrO-Bi₂O₃-B₂O₃ system were studied using powder X-ray diffraction (XRD) and differential thermal analysis (DTA). Quasi-binary sections were determined, and an isothermal section of the system in the subsolidus region at 600°C was constructed using the crossing spections method. A new ternary compound was found: SrBi₂B₄O₁₀. The existence of SrBi₂B₂O₇ was verified. Bi₂O₃-SrB₂O₄ and Bi₄B₂O₉-2SrO: 3B₂O₃ polytherms were constructed.     

Synthesis and Thermodynamic Properties of MgO·B_2O_3·4H_2O

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Interaction in the Li2Mo3O10-CO(NH2)2-H2O system at 25°C

The solubilities and solid phases in the Li₂Mo₃O₁₀-CO(NH₂)₂-H₂O system at 25°C are studied. A compound of composition Li₂Mo₃O₁₀ · 6CO(NH₂)₂ · 4H₂O and lithium trimolybdate decahydrate Li₂Mo₃O₁₀ · 10H₂O are found to exist. The Li₂Mo₃O₁₀ · 6CO(NH₂)₂ · 4H₂O ray crosses the solubility isotherm, which indicates the congruent solubility of the double compound in water. The density, refractive index, dynamic viscosity, surface tension, electrical conductivity, and pH of saturated solutions of the system are determined. The molar volume, equivalent electrical conductivity, reduced conductivity, and solution ionic strength isotherms are calculated. A strong correlation between all the property isotherms and the solubility is observed.     

Preparation,Crystal Structure and Vibrational Spectra of Ca2P2O6·2H2O and [Ca(H2O)3(H2P2O6)]·0.5(C12H24O6)·H2O

The calcium salts Ca₂P₂O₆ · 2H₂O ( 1 ) and [Ca(H₂O)₃(H₂P₂O₆)] · 0.5(C₁₂H₂₄O₆) · H₂O ( 2 ) were prepared and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pbca and compound 2 in the monoclinic space group P2₁/n. The crystal structure of compound 1 consists of chains of edge‐sharing [CaO₇] polyhedra linked by hypodiphosphate(IV) anions to form a three‐dimensional network. The crystal structure of compound 2 consists of alternated layers of crown ether and water molecules and respective ionic units. Within the layers of ionic units the Ca²⁺ cations are octahedrally coordinated by three monodentate dihydrogenhypodiphosphate(IV) anions and three water molecules. The IR/Raman spectra of the title compounds were recorded and interpreted, especially with respect to the [P₂O₆]^4– and [H₂P₂O₆]^2– groups. The phase purity of 2 was verified by powder diffraction measurements.     

Zur Kristallchemie von Ba3In2Zn5O11. Ein tOxoindat/zinkatsol;zinkat mit Zn10O20- und In4O16-Makropolyedern und erstmals O2− in tetraedrischer Koordination durch Zn2+

On the Crystal Structure of Ba₃In₂Zn₅O₁₁. An Oxoindate/zincatesol;zincate with Zn₁₀O₂₀ and In₄O₁₆ Macropolyhedra with Zn²⁺ in Tetrahedral Coordination by O^2? Ba₃In₂Zn₅O₁₁ was prepared for the first time by a flux technique and investigated by single crystal X-ray work. It crystallizes with cubic symmetry, space group T-F4 3m, a = 13.3588 Å, Z = 8. Zn²⁺ show tetrahedral coordination by O^2?, forming Zn₁₀O₂₀ macropolyhedra. In addition the nZn/Osol;O part of the crystal structure is made up of Zn₁₀O₂₀ parts. Edge connection of four InO₆ octahedra results in In₄O₁₆ groups. The crystal structure will be shown and discussed.     

Phase equilibrium in the system LaP3O9−NaPO3−P2O5

The phase diagram of the ternary system LaP₃O₉?NaPO₃?P₂O₅ was constructed through the use of a new compound NH₄LaP₄O₁₂. Ammonium lanthanum phosphate NH₄LaP₄O₁₂ crystallizes in the monoclinic system, space group C2/c, witha=7.941(4)Å,b=12.645(13)Å,c=10.702(9)Å, γ=110.00(5). The compound melts incongruently at 1198°C. Lanthanum pyrophosphate melts incongruently at 1160°C.     

Perovskite solid solutions in the BaO-CuO-Y2O3-Nb2O5 system

Freeze dried complex carboxylates are highly reactive precursors for complex perovskite solid solutions in the system BaO-CuO-Y₂O₃-Nb₂O₅ On thermal decomposition of the amorphous precursors the formation of complex crystalline phases begins at 600 °C. In most cases the themodynamically controlled phase composition is reached after a reaction time of two hours at about 900 °C. Beginning from the perovskite compound Ba₂YNbO₆ a partial substitution of Y by Cu or by a combination 2/3 Cu,1/3 Nb leads to extended fields of solid solutions with cubic perovskite structure. Substitution according to Y_0,5xBa₂(Y_1-0,5xCu_xNb)O_6+x is limited to x ≤ 0,4. A compound LBa₂Cu₂NbO₈ (x=2), well characterized for L=La, does not exist for L=Y. The composition of solid solutions depends on the preparation conditions. There are some signs for an inhomogeneous distribution of B-cations in the cubic perovskites.     

Preparation and Crystal Structure of PbRe2O6. An Example of the Re2O10 Unit with No Metal-Metal Bonding

Single crystals of PbRe₂O₆ were obtained from a stoichiometric mixture of PbO and ReO₃ at 500°C. The structure was determined by Patterson methods from X-ray four-circle diffractometer data using 2 270 (392 unique) reflections; R_W(F) = 0.036. PbRe₂O₆ crystallizes in the trigonal space group R3m with a = 10.359(6) Å, c = 11.092(6) Å and Z = 9. The compound is isotypic with the trigonal modification of PbNb₂O₆ and contains an Re₂O₁₀ unit. Unlike other compounds containing this species, there is no metal-metal bonding.     

Synthese von Y2O2(CN2) und Leuchtstoffeigenschaften von Y2O2(CN2):Eu

Synthesis of Y₂O₂(CN₂) and Luminescence Properties of Y₂O₂(CN₂):Eu Crystalline powders of the new compound Y₂O₂(CN₂) were prepared by solid state reactions from different mixtures of YCl₃/YOCl/Y₂O₃ and Li₂(CN₂) at temperatures between 620 °C and 650 °C. Structure refinements based on X‐ray powder diffraction revealed that trigonal Y₂O₂(CN₂) crystallizes with a structure that is closely related to that of Y₂O₂S, whereas linear N‐C‐N units replace sulphur atoms in Y₂O₂S. In addition, a hexagonal polytype of Y₂O₂(CN₂) was obtained in which a different stacking sequence of yttrium atoms creates a doubling of the c‐axis. Europium‐doped samples of Y₂O₂(CN₂) were prepared and the luminescence properties of Y₂O₂(CN₂):Eu are presented.     

Na7Y2(P2O7)2 (P3O10) – A New Layer and Tunnel Structure

A new layered phosphate, Na₇Y₂(P₂O₇) ₂(P₃O₁₀), containing both [P₂O₇]^4? and [P₃O₁₀]^5? groups, has been prepared. It crystallizes in the monoclinic space group P2/c with a = 16.205(4), b = 5.3746(9), c = 12.309(4) Å, β = 97.96(2)°, V = 1061.7(5) ų and Z = 2. The structure was solved and refined to R₁ = 0.0298 and wR₂ = 0.0698 for 1844 independent reflections with I > 2σ(I). It consists of layers of corner and edge-sharing YO₇ polyhedra, P₂O₇ and P₃O₁₀ groups. Each layer is built up from two parallel [YP₂O₇] slabs, held together by the P₃O₁₀ groups. This arrangement gives rise to intersecting tunnels within the layer. The Na⁺ cations are located in the tunnels and between the layers. Both P₂O₇ and P₃O₁₀ groups contain unshared oxygen atoms directed toward the interlayer space and toward the tunnels. The P₂O₇ groups show a staggered configuration. In addition to this original layered framework, the title compound provides the third example of a compound containing a mixed anion of [P₂O₇]^4? and [P₃O₁₀]^5?. The structure was compared with the two previously reported ones, containing such a mixed anion: NH₄Cd₆(P₂O₇) ₂(P₃O₁₀) [6] and Cs₂Mo₅O₂(P₂O₇)₃ · (P₃O₁₀) [7].     

MgO·3B2O3·3.5H2O的合成、表征及其溶液Raman光谱分析

硼是具有独特化学行为的稀有亲氧元素，在自然界中主要是以无机硼氧酸和硼氧酸盐形式存在。在硼酸盐晶体中，硼以聚合硼氧配阴离子形式存在，其中配位数为３和４的硼原子比可以有所不同，这使得硼酸盐种类繁多，结构复杂多样。至今，人们在自然界和实验室已发现了４种六硼酸镁盐犤１，２犦：MgO·３B２O３·nH２O（n＝７．５，７，６，５），它们的分子结构中都含有犤B６O７（OH）６犦２－基团。最近，我们在硼酸盐化学系列研究中，利用复盐氯柱硼镁石在沸点温度下的硼酸溶液中的相转化，合成了一种新的六硼酸镁盐MgO·３B２O３·３．…     

Die Kristallstruktur des Natriumoxohydroxoaluminathydrates Na2[Al2O3(OH)2] · 1,5 H2O

The Crystal Structure of the Sodium Oxohydroxoaluminate Hydrate Na₂[Al₂O₃(OH)₂] · 1.5 H₂O The crystal structure of the sodium oxohydroxoaluminate hydrate Na₂[Al₂O₃(OH)₂] ·s 1.5 H₂O (up to now described as Na₂O · Al₂O₃ · 2.5 H₂O and Na₂O · Al₂O₃ · 3 H₂O, respectively) was solved. The X-ray single crystal diffraction analysis (tetragonal, space group P-42₁m, a = 10.522(1) Å, c = 5.330(1) Å, Z = 4) results in a polymeric layered structure, consisting of AlO_3/2(OH) tetrahedral groups. Between these layers the Na⁺ ions are situated, which form tetrameric groups of face-linked NaO₆ octahedra. The involved O^2? ions are due to Al? O? Al bridges, Al? OH groups and water of crystallization. ²⁷Al and ²³Na MAS NMR investigations confirm the crystal structure analysis. The relations between the crystallization behaviour of the compound and the constitution of the aluminate anions in the corresponding sodium aluminate solution and in the solid, respectively, are discussed.     

Ein neues Kupfercobaltboratoxid mit isolierten B2O5-Baugruppen: Cu2Co(B2O5)O

On a New Copper Cobalt Borate Oxide with Isolated B₂O₅ Units: Cu₂Co(B₂O₅)O Single crystals of a new compound with the empirical formula Cu₂CoB₂O₆ were obtained by using a B₂O₃ flux technique. X-ray single crystal technique led to a new structure type. Cu₂CoB₂O₆ crystallizes monoclinic, space group C-P2₁/c (No. 14); a = 3.2250(6); b = 14.847(1); c = 9.1171(6) Å; β = 93.67°; Z = 4. All metal sites are octahedrally coordinated and form a two dimensional framework consisting of edge sharing octahedra ribbons. In addition one observes isolated B₂O₅-units and oxygen which is not coordinated to boron. The far relation to the crystal structure of the mineral Warwickite is illustrated.     

Synthesis and crystal structures of the manganous antimonates Mn2Sb2O7 and MnSb2O6

Mn₂Sb₂O₇ has been prepared by the solid state reaction of MnCO₃ and Sb₂O₃ at 1100°C, and its crystal structure determined from X-ray powder diffraction data. The compound is trigonal P3₁21 with a = 7.191, c = 17.398 Å, and the structure is fluorite-related, but not a distorted pyrochlore. The relationship between this structure and that of pyrochlore is discussed. MnSb₂O₆ was formed as a reaction intermediate and its structure has also been determined. This phase is trigonal P321 with a structure related to that of Na₂SiF₆ and is apparently a new polymorph, since MnSb₂O₆ has previously been stated to have either the orthorhombic columbite or the tetragonal trirutile structure.     

Thermal Characterization and Physico-Chemical Properties of Fe2O3−Mn2O3/Al2O3 Systems

The effect of ferric and manganese oxides dopants on thermal and physicochemical properties of Mn-oxide/Al₂O₃ and Fe₂O₃/Al₂O₃ systems has been studied separately. The pure and doped mixed solids were thermally treated at 400–1000°C. Pyrolysis of pure and doped mixed solids was investigated via thermal analysis (TG-DTG) techniques. The thermal products were characterized using XRD-analysis. The results revealed that pure ferric nitrate decomposes into Fe₂O₃ at 350°C and shows thermal stability up to1000°C. Crystalline Fe₃O₄ and Mn₃O₄phases were detected for some doped solids precalcined at 1000°C. Crystalline γ-Al₂O₃ phase was detected for all solids preheated up to 800°C. Ferric and manganese oxides enhanced the formation of α-Al₂O₃ phase at1000°C. Crystalline MnAl₂O₄ and MnFe₂O₄ phases were formed at 1000°C as a result of solid–solid interaction processes. The catalytic behavior of the thermal products was tested using the decomposition of H₂O₂ reaction. This revised version was published online in August 2006 with corrections to the Cover Date.