Synthesis and Crystal Structure of Rb6Pb5Cl16

The synthesis of a hitherto unknown 6 : 5 phase in the quasi-binary system RbCl/PbCl₂ and its structure determination is reported. The compound Rb₆Pb₅Cl₁₆ crystallizes in the tetragonal space group P4/mbm with a large variety of different coordination polyhedra for the cations. Special feature of the structure is a statistical distribution of Rb and Pb at one of the cation sites with a ratio of 1 : 3 as defined by electroneutrality. There is no evidence for symmetry reduction by ordering.     

Synthese und Kristallstruktur von Rb3PbCl5

Synthesis and Crystal Structure of Rb₃PbCl₅ The synthesis of the hitherto unknown compound Rb₃PbCl₅ in the quasi-binary system RbCl/PbCl₂ and its structure determination is reported. This 3 : 1-phase decomposes peritectoidally at 305 °C and crystallizes in a so far unknown structure type in the orthorhombic space group Pnma (a = 863.498(5) pm, b = 1573.11(1) pm, c = 838.875(5) pm). It shows typical structural characteristics of ns²-configurated cations, although there are more noble gas-configurated cations than ns²-configurated cations in the structure.     

Phase equilibria in the ternary system PbO−P2O5−PbCl2

Phase dependencies in the ternary system Pb₃Cl₂O₂?PbCl₂?Pb₁₀(PO₄)₆Cl₂, which is a partial system of the ternary system PbO?P₂O₅?PbCl₂, have been investigated by thermal, X-ray phase, microscopic, dilatometric and IR absorption analyses. The phase diagram of the Pb₃Cl₂O₂?PbCl₂?Pb₁₀(PO₄)₆Cl₂ system has been provided. The components have been found not to form any new chemical compounds.     

Mass Spectrometric Investigations of Thermodynamic Properties of the RbCl/GdCl3 System

The vaporization of pure RbCl, GdCl₃, and RbCl‐GdCl₃ samples of different phase compositions was investigated in the temperature range between 666 K and 982 K by use of the Knudsen effusion mass spectrometry. The gaseous species RbCl, Rb₂Cl₂, GdCl₃, and RbGdCl₄ were identified in the equilibrium vapours and their partial pressures were determined. The enthalpy of dissociation of RbGdCl₄(g), Δ_dissH°(859 K) = 263.1 ± 7.7 kJ mol^—1, was evaluated by second law treatment of the equilibrium partial pressures. The thermodynamic activities of RbCl and GdCl₃ were obtained at 800 K in the two‐phase fields {Rb₃GdCl₆(s) + liquid} and {RbGd₂Cl₇(s) + GdCl₃(s)}. The Gibbs free energies of formation of the pseudo‐binary phases Rb₃GdCl₆(s), Δ_fG°(800 K) = —75.1 ± 2.5 kJ mol^—1 and RbGd₂Cl₇(s), Δ_fG°(800 K) = —40.6 ± 1.2 kJ mol^—1, were evaluated from the thermodynamic activities of the components. The results are compared with the available literature data.     

Das System TlClPbCl2

A reinvestigation of the x-T diagram was performed using DTA and X-ray techniques. Four compounds exist in the sytem of $\text{TlCl}\text{PbCl}{}_2$. The transformations of Tl₃PbCl₅ and TlPb₂Cl₅ are discussed. The compound Tl₂PbCl₄ exists only within a temperature interval of about 20°C. A compound of the formula Tl₇Pb₃Cl₁₃ is reported for the first time. Crystallographic data of TlPb₂Cl₅, high and low Tl₃PbCl₅, and Tl₇Pb₃Cl₁₃ are presented.     

Syntheses,Characterization, and Fluorescence Properties of Four Divalent Lead Coordination Polymers based on Zwitterionic Ligands

Four novel divalent lead coordination polymers based on a series of zwitterionic ligands, Pb₂Cl₄L₁ ( 1 ), [Pb₂Cl₄L₂]·2H₂O ( 2 ), Pb₂Cl₂(CH₃COO)₂L₂ ( 3 ), and Pb₃Cl₄(NO₃)₂L₃ ( 4 ) were solvothermally synthesized and successfully characterized. Single crystal structure studies reveal that compound 1 is a chain structure based on the inorganic “PbCl₂” chain motif, whereas compounds 2 – 4 are sheet structures each constructed by inorganic “PbCl₂”, “PbCl(CH₃COO)”, and “Pb₃Cl₄” chain motifs. Hydrogen bonding interactions in term of C–H ··· Cl and C–H ··· O play a key role to form supramolecular 3D structures of 1 – 4 . Additionally, studies of solid state fluorescence indicate 1 – 4 emit in the ultraviolet and visible region that can be assigned to the inter‐ligand π*–π and/or π*–n transitions.     

Rb3LnCl6 · 2 H2O (Ln = La?Nd): Darstellung,Kristallstruktur und thermisches Verhalten

Rb₃LnCl₆ · 2 H₂O (Ln = La? Nd): Preparation, Crystal Structure, and Thermal Behaviour The compounds Rb₃LnCl₆ · 2 H₂O (Ln = La? Nd) were prepared from acetic acid as powders. The preparation from aqueous solutions does not yield the pure products because RbCl precipitates as first compound. The structure of Rb₃LaCl₆ · 2 H₂O was determined by X-ray analysis of a single crystal obtained from aqueous solution. The compounds with Ln = La? Nd are isotypic. They crystallize hexagonally in the space group P6₃/m (Rb₃LaCl₆ · 2 H₂O: a = 1 220.4(2) pm, c = 1 688.6(3) (pm) with Z = 6. Anionic trimeric units [Ln₃Cl₁₂(H₂O)₆]^3? are stacked along the c-axis over the corners of the unit cell. In the stacking frequency the units are rotated by 60° with respect to each other around the c-axis. The coordination number (C. N.) of Ln³⁺ is 8, which is satisfied by four bridging and two terminal chloride ions and two water molecules. The coordination spheres of the three rubidium ions in the different atomic positions are composed differently, their C.N. are 9, 8(+1) and 6(+6). The thermal dehydration of the compounds occurs in one step. The hydrates decompose at ca. 100°C to form the anhydrous compounds Rb₂LnCl₅ und RbCl since the anhydrous chlorides Rb₃LnCl₆ are thermodynamically stable above ca. 400°C only.     

Oxydationsprodukte intermetallischer Phasen. III. Tieftemperaturformen von K2Sn2O3 und Rb2Sn2O3 und eine Notiz über K2Ge2O3

Oxidation Products of Intermetallic Compounds. III. Low Temperature Forms of K₂Sn₂O₃ and Rb₂Sn₂O₃ and a Notice about K₂Ge₂O₃ By controlled oxidation of KSn (at 320°C) and RbSn (at 410°C) with O₂ the hitherto unknown low temperature forms of K₂Sn₂O₃ (a = 8.4100(8) Å) and Rb₂Sn₂O₃ (a = 8.6368(8) Å) are obtained, which are isotopic with cubic K₂Pb₂O₃. Oxidation at higher temperatures (at 510–5207°C) leads to the well-known HT-forms. The Madelung Part of Lattic Energie, MAPLE, is calculated for both compounds. K₂Pb₂O₃, Rb₂Pb₂O₃, Cs₂Pb₂O₃, and Cs₂Sn₂O₃ have been prepared too by oxidation of KPb, RbPb, CsPb, and CsSn. Oxidation of KGe (at 400°C) leads to the first oxogermanate(II), K₂Ge₂O₃ (cubic a = 8.339(1) Å, isotypic with K₂Pb₂O₃) together with K₆Ge₂O₇.     

Sub-solidus Relations in the System KF—PbF2 to high Pressures

The phase β-K_0.25Pb_0.75F_1.75 previously found in the KF-PbF₂ system appears to be metastable at low temperatures relative to a mixture of orthorhombic PbF₂ and a new phase suspected to be KPbF₃ II. KPbF₃ II transforms to KPbF₃ I at 298.5°C at atmospheric pressure. The KPbF₃ II/I transition line rises with pressure, but the substance appears to reversibly disproportionate above ～360°C, 5 kbar, possibly to a mixture of PbF₂ and K₄PbF₆. Instead of β-K_0.25Pb_0.75F_1.75, a mixture with this composition yielded, in addition to weak heat events due to the KPbF₃ II/I transition, strong heat events at 254.5°C and atmospheric pressure (thermal hysteresis ～13°C) which were ascribed to the PbF₂ orthorhombic/cubic transition. This transition rises with pressure to 673°C at 37.8 kbar.     

Synthese und Kristallstruktur von Blei(II)‐oxidhalogenid‐Alkoholaten mit unterschiedlichen Verknüpfungsvarianten von Pb4O4‐Heterokubaneinheiten

Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb₄O₄ Heterocubane‐like Subunits The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl^? and Br^?) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb₆(C₄H₈O₃)O₂Cl₆] (1) and [Pb₆(C₄H₈O₃)O₂Br₆] (2) . In a similar synthesis with PbI₂ as educt at temperature of 160 °C the two modifications β‐[Pb₆(C₄H₈O₃)O₂I₆] (3) and α‐[Pb₆(C₄H₈O₃)O₂I₆] (4) were found, whereas at a reaction temperature of 180 °C [Pb₉(C₂H₄O₂)(C₄H₈O₃)O₃I₈] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I₆ octahedra centered by lead is observed.     

Untersuchungen zum Zustandsdiagramm EuCl2–EuCl3

Investigations on the Phase Diagram EuCl₂–EuCl₃ The phase diagram EuCl₂–EuCl₃ was determined by difference‐thermoanalysis and the barogram of the system was determined by total pressure measurements of different compositions in function of temperature. By the results the phase diagram was precised. Eu₅Cl₁₁ decomposes at 565 °C in to EuCl_2,s and Eu₄Cl_9,s and shows a transition at 510 °C. Eu₄Cl₉ decomposes at 603 °C in to EuCl_2,s and Eu₁₄Cl_33,s. Eu₁₄Cl₃₃ decomposes at 612 °C peritectically in EuCl_2,s and a EuCl₃‐rich melt. Eu₁₄Cl₃₃ shows two high temperature transition points at 570 °C and 580 °C. The endothermal effect of compositions near Eu₁₄Cl₃₃ was interpreted as an endothermal formation of this compound. The eutectikum was detected between Eu₁₄Cl₃₃ and EuCl₃ to 60 ± 1 Mol‐% EuCl₃ at 530 °C.     

Liquidus diagram for the sodium orthophosphate-lead orthophosphate system

The Na₃PO₄Pb₃(PO₄)₂ system was studied by thermal analysis, high-temperature microscopy, and X-ray diffraction powder methods. The compound NaPbPO₄ melts congruently at 1117°C. An unidentified phase occurs in the vicinity of 10 mole% Pb₃(PO₄)₂. The system has eutectics at 44.5 and 96 mole% Pb₃(PO₄)₂, melting at 1074 and 1004°C, respectively. The respective melting points of Na₃PO₄ and Pb₃(PO₄)₂ are 1512 and 1015°C.     

Investigating Pb diffusion across buried interfaces in Pb(Zr0.2Ti0.8)O3 thin films via time‐of‐flight secondary ion mass spectrometry depth profiling

The diffusion of Pb through Pb(Zr_0.2Ti_0.8)O₃(PZT)/Pt/Ti/SiO₂/Si thin film heterostructures is studied by using time‐of‐flight secondary ion mass spectrometry depth profiling. The as‐deposited films initially contained 10 mol% Pb excess and were thermally processed at temperatures ranging from 325 to 700°C to promote Pb diffusion. The time‐of‐flight secondary ion mass spectrometry depth profiles show that increasing processing temperature promoted Pb diffusion from the PZT top film into the buried heterostructure layers. After processing at low temperatures (eg, 325°C), Pb⁺ counts were low in the Pt region. After processing at elevated temperatures (eg, 700°C), significant Pb⁺ counts were seen throughout the Pt layer and into the Ti and SiO₂ layers. Intermediate processing temperatures (400, 475, and 500°C) resulted in Pb⁺ profiles consistent with this overall trend. Films processed at 400°C show a sharp peak in PtPb⁺ intensity at the PZT/Pt interface, consistent with prior reports of a Pt₃Pb phase at this interface after processing at similar temperatures.     

Phase equilibria in the system Rb3PO4–Ba3(PO4)2

The system Rb₃PO₄–Ba₃(PO₄)₂ was investigated by thermoanalytical methods, X-ray powder diffraction, ICP, and FT-IR. On the basis of the obtained results its phase diagram was proposed. For this system with one intermediate compound, BaRbPO₄, we found that this compound melts congruently at 1700 °C, exhibits a polymorphic transition at 1195 °C and is high-temperature unstable. Also, the intermediate compound was subject to gradual decomposes to Ba₃(PO₄)₂ (the solid phase) and vaporization (with conversion of phosphorus and rubidium oxides into vapor phase). We also found that Rb₃PO₄ melts congruently at 1450 °C and shows a polymorphic transition at 1040 °C. Regarding Ba₃(PO₄)₂, we have confirmed that it melts congruently at 1605 °C and exhibits a polymorphic transition at 1360 °C.     

Reactivity of Ammonium Halides: Action of Ammonium Chloride and Bromide on Iron and Iron(III) Chloride and Bromide

Ammonium chloride and bromide, (NH₄)Cl and (NH₄)Br, act on elemental iron producing divalent iron in [Fe(NH₃)₂]Cl₂ and [Fe(NH₃)₂]Br₂, respectively, as single crystals at temperatures around 450 °C. Iron(III) chloride and bromide, FeCl₃ and FeBr₃, react with (NH₄)Cl and (NH₄)Br producing the erythrosiderites (NH₄)₂[Fe(NH₃)Cl₅] and (NH₄)₂[Fe(NH₃)Br₅], respectively, at fairly low temperatures (350 °C). At higher temperatures, 400 °C, iron(III) in (NH₄)₂[Fe(NH₃)Cl₅] is reduced to iron(II) forming (NH₄)FeCl₃ and, further, [Fe(NH₃)₂]Cl₂ in an ammonia atmosphere. The reaction (NH₄)Br + Fe (4:1) leads at 500 °C to the unexpected hitherto unknown [Fe(NH₃)₆]₃[Fe₈Br₁₄], a mixed‐valent Fe^II/Fe^I compound. Thermal analysis under ammonia and the conditions of DTA/TG and powder X‐ray diffractometry shows that, for example, FeCl₂ reacts with ammonia yielding in a strongly exothermic reaction [Fe(NH₃)₆]Cl₂ that at higher temperatures produces [Fe(NH₃)]Cl₂, FeCl₂ and, finally, Fe₃N.     

LiTiCl3: Synthesis and thermal behaviour

LiTiCl₃ is obtained as one example within an ample solid solution, Li_24–2nTi_nCl₂₄ (?4?n?10), by synpropotionation of TiCl₃ and Ti in the presence of LiCl (2:1:3 molar ratio) in sealed tantalum tubes at 750°C. It crystallizes with the inverse spinel-type structure according to (Li_0.67)^[4](Li_0.67Ti_1.33)^[4]Cl₄ with, at 25°C, a = 1048.62(4) pm, space group Fd3m. Thermal expansion is linear with α = 4.85 × 10^?5K^?1 up to about 300°C and thereafter, when the migration of Li⁺ from tetrahedral to octahedral interstices becomes increasingly important, it exhibits a relative decrease resulting, finally, in the phase transition to a NaCl-type structure that is observed for the first time at about 575°C.     

25℃时KCl-RbCl-1/2-C3H7OH-H2O四元体系的液-液-固相平衡研究

本文研究了25℃时,K+,Rb+,//Cl-1/2C3H7OH,H2O两个四元体系的相平衡。测定了KCl＋RbCl＋H2O三元体系液-固相间的关系和KCl/RbCl不同质量比（1/0、0.75/0.25、0.5/0.5、0.25/0.75和0/1）在1/2-C3H7OH-H2O两种溶剂存在时的5组四元体系的液-液-固相关系。绘制出全相图。探讨了盐析效应,并采用一个五元参数方程对双液线数据进行了关联,此外采用一个经过修改Eisen-Joffe方程对结线数据和饱和平衡数据进行拟合,得到的结果令人满意。     

Phase equilibria in the YPO4–Rb3PO4 system

The phase equilibria occurring in the YPO₄–Rb₃PO₄ system were investigated by thermoanalytical methods, X-ray powder diffraction, and ICP-OES. On the basis of the obtained results, its phase diagram is proposed. It was found that the system includes two intermediate compounds Rb₃Y(PO₄)₂ and Rb₃Y₂(PO₄)₃. The Rb₃Y(PO₄)₂ compound melts congruently at 1300 °C. The Rb₃Y₂(PO₄)₃ orthophosphate was previously unknown. This intermediate compound is high-temperature unstable and decomposes within the temperature range 1300–1330 °C to YPO₄ and Rb₃Y(PO₄)₂. The decomposition process is irreversible. It was found that the Rb₃Y₂(PO₄)₃ orthophosphate is isostructural with Rb₃Yb₂(PO₄)₃ and crystallizes in the cubic system (a = 1.70226 nm).     

Lead Mixed Oxyhalides Satisfying All Fundamental Requirements for High‐Performance Mid‐Infrared Nonlinear Optical Materials

To design high‐performance mid‐infrared (mid‐IR) nonlinear optical (NLO) materials, we have focused on the combination of a heavy metal lone pair cation, Pb²⁺ and mixed oxyhalides. A systematic investigation in PbO‐PbCl₂‐PbBr₂ system led us to discover the first examples of NLO lead mixed oxyhalides, namely, Pb₁₃O₆Cl₄Br₁₀, Pb₁₃O₆Cl₇Br₇, and Pb₁₃O₆Cl₉Br₅. All the reported materials have remarkably comprehensive properties including broad IR transparency (up to 14.0 μm), qualified second harmonic generation (SHG) responses (0.6–0.9×AgGaS₂), wide band gaps (3.05–3.21 eV), and ease of crystal growth. Interestingly, a centimeter‐sized single crystal (2.9×1.3×0.5 cm³) of Pb₁₃O₆Cl₉Br₅ revealing a wide transparent range (0.384–14.0 μm) and high laser damage threshold (LDT) (14.6×AgGaS₂) has been successfully grown in an open system. The study suggests that all the reported mixed oxyhalides are outstanding candidates for mid‐IR NLO materials.     

Ag2Pb8O7Cl4, Ein neues Blei(II)-oxidhalogenid mit Silber

Ag₂Pb₈O₇Cl₄, a New Member of Lead(II) Oxyhalides with Silver Ag₂Pb₈O₇Cl₄ is one among other products of the thermal decomposition of AgPb₄O₄Cl. Ag₂Pb₈O₇Cl₄ can be prepared directly by heating the binary components within a temperature range from 590°C to 620°C. The crystal structure was solved by single crystal X-ray methods. The compound crystallizes monoclinic with a = 12.411(4) Å, b = 17.99(3) Å, c = 14.785(4) Å, β = 147.01(2)°, Z = 4 with the space group P2₁/c. Ag₂Pb₈O₇Cl₄ shows remarkable structural features, e.g. silver tetrahedrally surrounded by chlorine.