Crystal structure and stability of Tl2CO3 at high pressures

The crystal structure of dithallium carbonate, Tl₂CO₃ (C2/m, Z = 4), was investigated at pressures of up to 7.4 GPa using single‐crystal X‐ray diffraction in a diamond anvil cell. It is stable to at least 5.82 GPa. All atoms except for one of the O atoms lie on crystallographic mirror planes. At higher pressures, the material undergoes a phase transition that destroys the single crystal.     

Reciprocal system 3Tl2S + Bi2Se3 ↔ 3Tl2Se + Bi2S3

The reciprocal system 3Tl₂S + Bi₂Se₃ ? 3Tl₂Se + Bi₂S₃ has been investigated by DTA, X-ray powder diffraction analysis, and emf measurements. Some polythermal sections and the isothermal section at 500 K of the phase diagram and the projection of the liquidus surface of this system have been constructed, and the types and coordinates of the invariant and univariant equilibria have been determined. The existence of wide regions of quaternary solid solutions based on the binary compounds Tl₂S, Tl₂Se, Bi₂S₃, and Bi₂Se₃, and solid solutions between the temary compounds TlBiS₂ and TlBiSe₂ have been established.     

Tl2Te and its relationship with Tl5Te3

The crystal structure of Tl₂Te, dithallium telluride, has been determined by single‐crystal X‐ray diffraction. The analysis of the structure shows that this compound is the first known representative of a new crystal structure type. The structural relationship with the related Tl₅Te₃ phase is discussed.     

[Tl3Cp2][CpMo(CO)3] – ein Salz mit dem neuartigen Kation [Tl3Cp2]+. Neuuntersuchung der Struktur von MCp (M = In,Tl)

[Tl₃Cp₂][CpMo(CO)₃] – a Salt with the New Cation [Tl₃Cp₂]⁺. Structural Reinvestigation of MCp (M = In, Tl) Single crystals of MCp [M = In ( 1 ), Tl ( 2 )] could be obtained from saturated THF solutions. Mo(CO)₆ reacts with TlCp in toluene under reflux conditions to the complex salt [Tl₃Cp₂][CpMo(CO)₃] ( 3 ). 3 was characterized by NMR, IR and MS spectra. In addition, 1 – 3 were investigated by X-ray structure determinations. According to this, 1 and 2 crystallize isotypical in the centrosymmetric space group C2/c and form zig-zag-shaped chain polymers in the solid state. 3 crystallizes in the space group P2₁/n. In 3 , u-shaped units [Tl₃Cp₃Mo(CO)₃] are arranged through additional Tl–CO contacts to helices along [010].     

K2CO3-Na2CO3-Li2CO3-H2O四元体系288K的相平衡

水盐体系;碳酸盐;溶解度;盐湖卤水;K2CO3-Na2CO3-Li2CO3-H2O四元体系288K的相平衡     

The Local Atomic Structures of Liquid CO at 3.6 GPa and Polymerized CO at 0 to 30 GPa from High‐Pressure Pair Distribution Function Analysis

The local atomic structures of liquid and polymerized CO and its decomposition products were analyzed at pressures up to 30 GPa in diamond anvil cells by X‐ray diffraction, pair distribution function (PDF) analysis, single‐crystal diffraction, and Raman spectroscopy. The structural models were obtained by density functional calculations. Analysis of the PDF of a liquid CO‐rich phase revealed that the local structure has a pronounced short‐range order. The PDFs of polymerized amorphous CO at several pressures revealed the compression of the molecular structure; covalent bond lengths did not change significantly with pressure. Experimental PDFs could be reproduced with simulations from DFT‐optimized structural models. Likely structural features of polymerized CO are thus 4‐ to 6‐membered rings (lactones, cyclic ethers, and rings decorated with carbonyl groups) and long bent chains with carbonyl groups and bridging atoms. Laser heating polymerized CO at pressures of 7 to 9 GPa and 20 GPa resulted in the formation of CO₂.     

Die Systeme Tl3SbS3-Tl3AsS3 und TlSbS2-TlAsS2

The influence of structural relationships between the components of (pseudo)binary systems with no intermediate compounds on the type of phase diagram was investigated. Structurally and chemically closely related Tl₃SbS₃ and Tl₃AsS₃ form a complete solid solution series whereas crystallographically different TlSbS₂ and TlAsS₂ constitute an eutectic type system.

     

Phase diagram for the Tl2Te-Bi2Te3 system

The phase equilibria in the Tl₂Te-Bi₂Te₃ system were studied by means of cooling curve determination, differential thermal analysis and X-ray diffraction methods; the results obtained with the former two methods were compared. The phase diagram established for the system differed considerably from three others published previously.

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Zusammenfassung Mittels Differentialthermoanalyse, der Bestimmung der Abkühlungskurven und röntgendiffraktionsaufnahmen wurde das Phasengleichgewicht des Systemes Tl₂Te-Bi₂Te₃ untersucht. Die Ergebnisse ersterer beider Methoden wurden miteinander verglichen. Das für das System entwickelte Phasendiagramm weicht erheblich von drei vorangehend veröffentlichten Phasendiagrammen ab.

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, l₂T-³ ₂₃. . .

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The present work was financed by the Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocaw, from grant CPBP 01.12.     

Phase equilibria in the Tl2Te-PbTe-Bi2Te3 system

Phase equilibria in the Tl₂Te-PbTe-Bi₂Te₃ system were studied by differential thermal analysis, X-ray powder diffraction, and microhardness measurements. Some polythermal sections and isothermal (at 600 and 800 K) sections of the phase diagram and a projection of the liquidus surface were constructed. It was shown that the system is characterized by the formation of solid solutions with the Tl₅Te₃ structure (??) and solid solutions based on PbTe (??₁), Tl₂Te (??), Bi₂Te₃ (??), and two TlBiTe₂ (??₂ and ?á?₂) phases. Their homogeneity regions were determined. The liquidus surface consists of the primary crystallization fields of the ??-, ??₁-, ?á?₂-, and ??-phases and the compounds PbBi₂Te₄ and PbBi₄Te₇. The liquidus of the ?? phase is degenerate. The primary crystallization fields of the phases were determined, and the types and coordinates of in- and monovariant equilibria were found.     

Phase diagram of the B-B2O3 system at 5 GPa: experimental and theoretical studies

X-ray diffraction with synchrotron radiation has been used to study in situ the chemical interaction of beta-rhombohedral boron with boron (III) oxide and phase relations in the B-B2O3 system at pressures up to 6 GPa in the temperature range from 300 to 2800 K. The B-B2O3 system has been thermodynamically analyzed, and its equilibrium phase diagram at 5 GPa has been constructed. Only one thermodynamically stable boron suboxide, B6O, exists in the system. It forms eutectic equilibria with boron and B2O3.     

β‐Tl2SO4

The ambient‐temperature form of dithallium sulfate, β‐Tl₂SO₄, is similar to β‐K₂SO₄ and is characterized by isolated sulfate tetrahedra and two different thallium sites with coordination numbers 9 and 11. All the atoms, except one O atom, lie on mirror planes. In spite of there being a high concentration of Tl⁺ cations, the stereochemical activity of the 6s² pairs is low, similar to that of isotypic Tl₂XO₄ compounds (X = Cr and Se). This behaviour is the consequence of both weak Tl—O bonds and strong X—O bonds, because in a Tl—O—X linkage the electronic cloud of the O²⁻ anion is strongly distorted and displaced towards X, resulting in a low negative charge in the face of the Tl atom. Consequently, the Coulombic repulsions between the lone pair and the O²⁻ anions are weak. All of the Tl₂XO₄ compounds exhibit the same open packing of A⁺ cations and [XO₄]²⁻ anions as their isotypic alkali counterparts.     

Die Kristallstrukturen von Tl2AgI3 und NaAgI2 · 3 H2O

Crystal Structure Investigations of Tl₂AgI₃ und NaAgI₂ · 3 H₂O Tl₂AgI₃ was synthesized by the reaction of TlI with AgI in aqueous HI (25%) in a pressure vessel. The compound crystallizes in the rhombohedral space group R3 ; a = 1044,3(2); c = 1993,5(3)pm; Z = 9. The crystal structure contains trinuclear anions [Ag₃I₈]^5? and [ITl₆]⁵⁺ octahedra. The anions are composed of two AgI₄-tetrahedra which are connected to an AgI₆ octahedron via common faces. Single crystals of NaAgI₂ · 3 H₂O were formed by reaction of NaI with AgI in aqueous solution. The compound crystallizes in the orthorhombic space group Pbca with lattice parameters a = 711,2(2); b = 939,8(3); c = 2462,2(4) pm; Z = 8. The crystal structure is built up by polymeric layers [AgI_3/3I_½^1/2?] of corner sharing AgI₄ tetrahedra (GaOCl type) and [Na(H₂O)_4/2(H₂O)I_½^1/2+] octahedra chains.     

205Tl NMR studies: Ion pairing of Tl+ and (CH3)2Tl+ with NO 3 − and ClO 4 − in various solvents

The concentration dependence of the²⁰⁵Tl chemical shifts of Tl⁺ and of (CH₃)₂Tl⁺ ions was determined in several solvents with NO ₃ ^– and ClO ₄ ^– counterions. In general, increased ion pairing caused a low-frequency shift of the²⁰⁵Tl resonance, with the exceptions of (CH₃)₂TlNO₃ inn-butylamine and TlNO₃ in N,N-dimethylformamide (DMF) and in hexamethylphosphorotriamide (HMPA). In HMPA,²⁰⁵Tl linewidths of both Tl⁺ and (CH₃)₂Tl⁺ increased dramatically with dilution below 0.1M. Analysis of the data allowed ion-pair formation constants and²⁰⁵Tl chemical shifts for the ion-paired cation and for the free (solvated) cation to be estimated for some of the solvents.     

影响Li2ZrO3在高温下吸收CO2的因素

于不同条件下合成了一系列用于在高温下吸收CO2的Li2ZrO3材料.用扫描电子显微镜（SEM）、X射线粉末衍射仪（XRD）分别观察和评价了合成材料的表面形貌与结构特征,使用热重分析（TG）仪研究了Li2ZrO3材料吸收CO2的性能.实验结果表明,合成温度影响材料的结构和表面性质,从而影响材料吸收CO2的性能,在800 ℃合成的Li2ZrO3材料吸收CO2的性能比较好,合成温度过高或过低都不利于材料吸收CO2.同时,气氛中CO2的含量也影响材料吸收CO2的速度,在CO2体积百分含量比较高的条件下,材料吸收CO2的速度较快.此外,本研究不进行任何元素的添加即可合成出吸收性能比较好的Li2ZrO3材料.     

Solubility, complex formation, and redox reactions in the Tl2O3-HCN/CN(-)-H2O system. Crystal structures of the cyano compounds Tl(CN)3.H2O, Na[Tl(CN)4].3H2O, K[Tl(CN)4], and Tl(I)[Tl(III)(CN)4] and of Tl(I)2C2O4

Thallium(III) oxide can be dissolved in water in the presence of strongly complexing cyanide ions. Tl(III) is leached from its oxide both by aqueous solutions of hydrogen cyanide and by alkali-metal cyanides. The dominating cyano complex of thallium(III) obtained by dissolution of Tl2O3 in HCN is [Tl(CN)3(aq)] as shown by 205Tl NMR. The Tl(CN)3 species has been selectively extracted into diethyl ether from aqueous solution with the ratio CN-/Tl(III) = 3. When aqueous solutions of the MCN (M = Na+, K+) salts are used to dissolve thallium(III) oxide, the equilibrium in liquid phase is fully shifted to the [Tl(CN)4]- complex. The Tl(CN)3 and Tl(CN)4- species have for the first time been synthesized in the solid state as Tl(CN)3.H2O (1), M[Tl(CN)4] (M = Tl (2) and K (3)), and Na[Tl(CN)4].3H2O (4) salts, and their structures have been determined by single-crystal X-ray diffraction. In the crystal structure of 1, the thallium(III) ion has a trigonal bipyramidal coordination with three cyanide ions in the equatorial plane, while an oxygen atom of the water molecule and a nitrogen atom from a cyanide ligand, attached to a neighboring thallium complex, form a linear O-Tl-N fragment. In the three compounds of the tetracyano-thallium(III) complex, 2-4, the [Tl(CN)4]- unit has a distorted tetrahedral geometry. Along with the acidic leaching (enhanced by Tl(III)-CN- complex formation), an effective reductive dissolution of the thallium(III) oxide can also take place in the Tl2O3-HCN-H2O system yielding thallium(I), while hydrogen cyanide is oxidized to cyanogen. The latter is hydrolyzed in aqueous solution giving rise to a number of products including (CONH2)2, NCO-, and NH4+ detected by 14N NMR. The crystalline compounds, Tl(I)[Tl(III)(CN)4], Tl(I)2C2O4, and (CONH2)2, have been obtained as products of the redox reactions in the system.