Synthèse et structure cristalline de Tl(I)Tl(III)0,6Bi(III)0,4(CrO4)2

The crystal sructure of Tl(I)Tl(III)_0.6Bi(III)_0.4(CrO₄)₂ was determined with a single crystal. The unit-cell is orthorhombic, space group Pnma. The cell parameters are: a(Å) = 14.652(2), b(Å) = 5.7085(12), c(Å) = 8.620(2), Z = 4, ρ = 5.92 g cm⁻³. The structure is isomorphous with Tl(I)Tl(III)(CrO₄)₂ and was refined to the final factor R = 0.072 (R_w = 0.10), using 1434 independent reflections (I > 4σ(I)). A three-dimensional framework and, noteworthy, trivalent bismuth atoms located in a quasi-regular octahedral surrounding, constitute the main features of the structure.     

Synthesis and Properties of Uranosilicates M[HSiUO6] · nH2O (M = NH4+, Li,Na, K,Rb, Cs)

A complete set of uranosilicates M[HSiUO₆] · nH₂O of alkali metals and ammonium was obtained under hydrothermal conditions. The functional and phase similarity of the compounds was proved by X-ray phase analysis and IR spectroscopy. The effect of water molecules on the structures of hydrated and anhydrous uranosilicates and the nature of water in these compounds were elucidated by studying hydration-dehydration processes. The dependence of the X-ray and thermal properties of the compounds on the nature of interlayer atoms was considered.     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.     

Crystal structure of salts of the trans-[Rh(NH3)2(NO2)4]− anion with K+, Cs+, Ag+, and (CH3)4N+ cations

Complex rhodium(III) salts with the composition trans-M[Rh(NH₃)₂(NO₂)₄], where M = K⁺, Cs⁺, Ag⁺, and N(CH₃) ₄ ⁺ , are prepared and characterized. The molecular and crystal structures are determined by X-ray crystallography.     

MAlH4(M=Li,Na)储氢材料*

氢能是一种新型的清洁能源,有望替代碳经济,而氢的储存是氢能应用的关键。近年来,研究集中在具有储氢容量高和可逆性好等优点的固态储氢材料上。许多新型储氢材料不断出现,其中以MAlH₄(M=Li, Na)为代表的金属复合氢化物体系被认为是最有前景的储氢材料之一。本文综述了MAlH₄(M=Li, Na)作为可逆储氢材料的研究现状,主要从吸放氢反应、储氢性能、反应机理、理论计算和存在的问题等方面进行了讨论,并指出其相关发展趋势。     

Preparation and photoluminescent properties of Eu(III) containing M-layered silicates (M = Li,Na, K,Rb, Cs)

Eu(III) containing M-layered silicates (M = Li, Na, K, Rb, Cs) were prepared using the layered silicates, such as ilerite, magadiite, and kenyaite, as a host matrix and the luminescence properties were investigated. The results from the luminescence measurements indicated that the luminescence properties in the EuM-layered silicate system depended strongly on the types of host matrices and alkali cations. Among the EuM-layered silicates, EuM-ilerite exhibited the strongest luminescence intensity for all alkali cations, whereas EuM-kenyaite exhibited relatively weak luminescence intensity. The luminescence intensity was significantly increased by heat treatment at high temperature, mainly due to the phase change of host matrices and the presence of alkali cations in the host matrices. Particularly, the luminescence intensity of EuM-layered silicate calcined at 1,000 °C increased with the increase of the ion size of alkali cations.     

Vibrational spectra of double oxalates of the type M(I)2Cu(C2O4)(2)·2H2O (MI=Na+, K+, NH4+)

The infrared and Raman spectra of Na2Cu(C2O4)(2)·2H2O, K2Cu(C2O4)(2)·2H2O and (NH4)2Cu(C2O4)(2)·2H2O were recorded and briefly discussed on the basis of their structural peculiarities and by comparison with the vibrational spectra of other metallic oxalates.     

Superacid Univalent Metal Phosphites (MH2PO3)2· H3PO3 (M = Rb,Tl(I)) and MH2PO3· H3PO3(M = K,Cs): Synthesis and Structure

By reacting the K, Rb, Cs, or Tl carbonates with excess phosphoric acid, crystals of superacid phosphites, namely, (RbH₂PO₃)₂· H₃PO₃(I), (TlH₂PO₃)₂· H₃PO₃(II), KH₂PO₃· H₃PO₃(III), -CsH₂PO₃· H₃PO₃(IV), and -CsH₂PO₃· H₃PO₃(V), were synthesized. Their structures were determined by single-crystal X-ray diffraction analysis at 150 K. Crystals I: triclinic system, space group , a= 7.713(2) Å, b= 8.679(3) Å, c= 9.235(3) Å, = 79.36(3)°, = 67.60(2)°, = 88.13(3)°, R ₁= 0.0252; crystals II: triclinic system, space group , a= 7.690(3) Å, b= 8.494(3) Å, c= 9.292(4) Å, = 79.48(3)°, = 66.72(3)°, = 85.45(3)°, R ₁= 0.0485; crystals III: monoclinic system, space group P2₁/c, a= 8.726(3) Å, b= 12.182(4) Å, c= 6.354(2) Å, = 104.14(3)°, R ₁= 0.0241; crystals IV: orthorhombic system, space group P2₁2₁2₁, a= 6.033(1) Å, b= 6.444(1) Å, c= 18.345(4) Å, R ₁= 0.0172; crystals Vare monoclinic, space group C2/c, a= 9.990(3) Å, b= 12.197(4) Å, c= 6.866(2) Å. = 118.14(3)°, R ₁= 0.0181. The hydrogen bonding systems form corrugated bands (Iand II), bent layers (III), individual tubes with rectangular cross sections (V), or a three-dimensional framework (IV). A comparative analysis of the crystal structures of acid phosphites with different compositions was performed.     

超碱金属阳离子BM_6~+,CM_5~+,NM_4~+,OM_3~+和FM_2~+(M=Li,Na)的理论研究

采用从头算方法研究了一系列超碱金属阳离子BM6+,CM5+,NM4+,OM3+和FM2+(M=Li,Na).在MP2/6-311+G(d)水平上优化了这些体系的几何结构,并对频率进行了分析.计算得到它们最稳定结构分别具有Oh,D3h,Td,D3h和D∞h对称性.中心原子电负性越高,与配体碱金属原子之间的键长越短,相互作用越强.在CCSD(T)/6-311+G(3d,f)理论水平下计算了阳离子体系的垂直电子亲和势(EEA,v),EEA,v值的范围在3.26～3.86 eV之间,都低于Cs原子的第一电离势(3.90 eV).     

Complexation thermodynamics of imine-type bis(benzocrown ether)s. Part I. Sandwich complexation of K+, Rb+, Cs+ and Tl+ with polymethylene andm-Phenylene bridged carbonylhydrazones of 4′-formylbenzo-15-crown-5

The complexation thermodynamics of polymethylene andm-phenylene bridged carbonylhydrazones of 4-formylbenzo-15-crown-5 with K⁺, Rb⁺, Cs⁺ and Tl⁺ was investigated by spectrophotometric titrations in methanol at 283–313 K. The carbonylhydrazone sequences in the bridge of the bis(benzocrown ether)s are optical sensors for the sandwich complexation of metal ions. Within the homologous series of polymethylene bridged carbonylhydrazones a stability peak was found for the sandwich complexes of the propylene bridged compound with K⁺, Rb⁺ and Tl⁺. The potassium complex of this ligand shows the highest stability constant compared to all other known bis(benzo-15-crown-5) complexes with K⁺ in methanol.In terms of thermodynamics the formation of intramolecular sandwich complexes is driven by a gain of enthalpy. The unusual high gains of enthalpy and losses of entropy on formation of the most stable sandwich complexes allow us to propose an additional stabilization of the sandwich arrangement by intramolecular hydrogen bridge bonds. The H ^o-TS ^o diagram gave an excellent straight line allowing discussion of the enthalpy-entropy compensation effect at these complexation reactions.     

Synthesis and Crystal Structure of Tetraamminelithium-Rubidiumtriselenide, Li(NH3)4RbSe3, and Pentaamminesodium-Rubidiumtriselenide-Ammonia(1/3), Na(NH3)5RbSe3 · 3NH3

Summary. The ammoniates Li(NH₃)₄RbSe₃ and Na(NH₃)₅RbSe₃·3NH₃ were prepared by the reduction of Rb₂Se₅ with lithium or sodium in liquid ammonia. Single crystals were isolated and characterized by X-ray structure analysis using low temperature techniques. Both compounds contain triselenide anions Se₃^2–, which coordinate to rubidium cations forming ¹[RbSe₃]^– or ¹[Rb(NH₃)₂Se₃]^– chains. The chains are separated in the crystal structures by the homoleptic ammine complexes Li(NH₃)₄⁺ and Na(NH₃)₅⁺.     

Na,Rb‖F,Br three-component reciprocal system and analysis of the Na,M‖F,Br (M = K,Rb, and Cs) series

Solid-phase reactions were studied by differential thermal analysis and X-ray powder diffraction in a sample whose composition corresponds to the complete conversion point K of the Na,Rb‖F,Br three-component reciprocal system. A stable diagonal and a metastable diagonal were studied, and the parameters of two ternary eutectics were determined.     

Structure et étude raman du composé (C3H7NH3)2HgCl4

The structure of (C₃H₇NH₃)₂HgCl₄ is orthorhombic, M_r = 462.6, Abma, a = 7.991(2) Å, b = 7.779(2) Å, c = 23.519(2) Å, Z = 4, V = 1462(1) ų, D_m = 2.05(2), D_x = 2.10 mg/m⁻³, λ(AgKα) = 0.56083 Å, μ(AgKα) = 61.02 cm⁻¹, T = 300 K, R = 0.032, R₂ = 0.027 for 1188 reflections with I < 0.5σ(I). The structure is of the K₂NiF₄ type and consists of HgCl₆ octahedra which are held together through equatorial Cl atoms forming a two-dimensional (HgCl₄)²⁻_n layer perpendicular to the c axis (HgCl_ax is shorter than the HgCl_eq). The C₃H₇NH⁺₃ cations inserted between these layers are disordered and joined to the layers by hydrogen bonding. The Raman spectra between 10 and 400 cm⁻¹ have been recorded and some characteristic (HgCl₄)²ⁿ⁻_n layer frequencies assigned. Thermal analysis indicates two singularities at 195 and 205 K.     

Solubility of AIVUO6·nH2O (AI = H,Na, K,Rb, Cs,Tl) Uranovanadates

The solubility of uranovanadates of the series A^IVUO₆·nH₂O (A^I = H, Na, K, Rb, Cs, Tl) in water and aqueous solutions of acids under various conditions were determined. On this basis standard Gibbs functions of formation were calculated, which made it possible to consider the state of these compounds under conditions not covered by the experiment.     

Tripotassium Trichrome (III) Tetraphosphate K3Cr3(PO4)4: Synthèse, Étude Structurale,Caractérisation et Conductivité Ionique

The potassium chromium (III) phosphate K₃Cr₃(PO₄)₄ is prepared by a solid state reaction at 1173 K from a mixture of K₂CO₃, NH₄H₂PO₄, and (NH₄)Cr₂O₇. It is structurally characterized by single-crystal X-ray diffraction. It crystallizes in the Cmca (n°64) space group with a = 10.524(4) Åi, b = 20.466(6) Åi, c = 6.374(2) Åi, V = 1372.9(8) Åi³, Z = 4, R(F²) = 0.0452, and R _W (F²) = 0.1184 for 790 reflections with I > 2σ(I). The structure consists of CrO₆ octahedra and PO₄ tetrahedra sharing corners and edges to form a two-dimensional framework. The K⁺ cations are located in the interlayer space. Conductivity measurement leads to σ = 47.32 10^?5 Ω^?1 m^?1 at 729 K. K₃Cr₃(PO₄)₄ is a better ionic conductor than K₃Cr₃(AsO₄)₄ at the same temperature.     

Aqueous sol–gel synthesis,thermoanalytical study and luminescent properties of M0.05Eu0.05Ca0.9MoO4 (M=Li,Na, K,Rb, Cs) nanocrystallites

Nano-sized M_0.05Eu_0.05Ca_0.9MoO₄ (M=Li, Na, K, Rb, Cs) ceramics have been successfully synthesized by an aqueous sol–gel synthesis method using a tartaric acid as a ligand. In order to reveal the influence of the peculiarities of the nature of dopants effect into the crystallization of CaMoO₄ double oxide, the thermal analysis of the as-prepared gels was performed. In addition, infrared spectroscopy was used in order to identify the functional groups from the characteristic stretching vibrations in the M–Eu–Ca–Mo–O tartrate gel precursors. Besides, to confirm the dynamics of growing crystallites in the final ceramics and to reveal the morphological changes on the surface, the x-ray diffraction and scanning electron microscopy were applied. Finally, photoluminescence measurements were used to estimate the optical properties of europium oxide as a dopant in the samples according to the nature of alkali metal. Therefore, according to the obtained results, it was estimated that luminescence intensity of Eu³⁺ ions is mainly affected by the chemical reaction, which takes place at about 973 K of temperature. This effect was partly confirmed from the results of the thermal decomposition of M–Eu–Ca–Mo–O tartrate gel precursors with an endothermic behaviour in the DSC curve, which indicates the crystallization mechanism of the CaMoO₄ double oxide.

     

三元体系MCl-SbCl~3-HOAc (M=Li,Na; 25℃)的研究

测定了三元体系MCl-SbCl~3-HOAc(M=Li,Na;25℃)的溶度数据和饱和溶液的折光指数,并绘制了相应的溶度图及其折光指数曲线。M=Li时,体系的溶度曲线和折光指数曲线均由三支组成,分别与LiCl.0.5HOAc,LiCl,SbCl~3相对应。M=Na时,体系属于简单共饱型,无任何新相形成。研究结果表明,当M分别是Li,Na或K,NH~4,Rb,Cs时,体系的物理化学行为有着极为显著的不同,说明MCl-SbCl~3-HOAc(M=Li,Na,K,NH~4,Rb,Cs)体系可以作为区分碱金属系列阳离子性质差别的典型体系。     

Li1.3Ti1.7Al0.3(PO4)3与Na+的离子交换

锂离子传导材料Li_1.3Ti_1.7Al_0.3(PO₄)₃是具有NASICON结构的功能材料, 与Na⁺进行离子交换具有选择性高的特性. 研究了在不同温度条件下NaCl和LiCl水溶液中Li_1.3Ti_1.7Al_0.3(PO₄)₃上的Na/Li离子交换行为. 实验结果表明, 升高温度能显著提高Li_1.3Ti_1.7Al_0.3(PO₄)₃的Na/Li交换反应速率, 提高LiCl中杂质Na的分离效果.     

Copper(I) π-Complexes with Alkyne Ligands: Synthesis and Crystal Structure of M[CuCl2(HOCH2C≡CCH2OH)] (M = K+, NH+ 4)

Crystals of anionic complexes of the composition M[CuCl₂(HOCH₂CCCH₂OH)], where M = NH₄ ⁺ (I), K⁺ (II), were isolated from concentrated aqueous solutions of CuCl and MCl (M = NH₄ ⁺, K⁺) in the presence of 2-butyne-1,4-diol. Their structures were studied by X-ray diffraction analysis. Isostructural crystals I and II are orthorhombic; Z = 8, space group Ibam; a = 6.735(1) and 6.666(2) Å, b = 17.206(3) and 16.874(6) Å, c = 15.172(3) and 15.032(4) Å, V = 1758(1) and 1691(1) ų, respectively. The compounds are built of individual [CuCl₂(HOCH₂CCCH₂OH)] anions; the NH₄ ⁺ (I) or K⁺ (II) cations are arranged in the voids between the anions. The -coordinated Cu(I) atoms have trigonal-planar environment of two chlorine atoms and CC bond of the 2-butyne-1,4-diol molecule. The Cu–(CC) distances in the -core are 1.892(4) and 1.887(6) Å, CC are 1.233(5) and 1.228(5) Å in I and II, respectively. In complex I, additional hydrogen bonds Cl···H–NH₃ (Cl···H 2.43(4) Å) and O···H–NH₃ (O···H 1.97(3) Å) stabilize the structure.