Phase equilibria in the quaternary systems Li‖F,Cl,Br,CrO4 and Li‖F,Cl,Br,WO4

Phase equilibria in the quaternary systems Li‖F,Cl,Br,CrO₄ and Li‖F,Cl,Br,WO₄ were studied by differential thermal analysis. In these systems, the stability of continuous series of solid solutions based on lithium chloride and bromide is preserved. The number and compositions of crystallizing phases in the systems Li‖F,Cl,Br,CrO₄ and Li‖F,Cl,Br,WO₄ were confirmed by X-ray powder diffraction analysis.     

Phase complex of the Na,K‖Br,MoO4 system

The Na,K‖Br,MoO₄ system was studied by differential thermal analysis and X-ray powder diffraction. It was established that the liquidus surface consists of the crystallization fields of the initial components and the incongruently melting compound NaKMoO₄. The coordinates of three nonvariant points were determined, which represent one eutectic, E ^Δ, and two peritectics, P ₁ ^Δ , and P ₂ ^Δ , with the melting points 472, 512, and 538°C, respectively, and the specific enthalpies of melting Δ_melt H = 177, 230, and 184 kJ/kg, respectively.     

Na,Ba∥F,Br three-component reciprocal system and analysis of the Na,Ba∥F,Hal (Hal=Cl, Br, and I) series

A set of isopleths was studied using differential thermal analysis (DTA), the liquidus surface projection on the concentration square was plotted, and parameters were determined for the alloys corresponding to two ternary eutectics and one peritectic of the Na,Ba∥F,Br three-component reciprocal system. Solid-phase reactions in a sample containing 66.7% BaBr2+33.3% (NaF) ₂ were also studied by DTA. The results were used to analyze the entire series of the Na,Ba∥F,Hal (Hal = Cl, Br, and I) systems.     

Study of series of the M1,M2‖F,Cl,Br quaternary reciprocal systems (M1 and M2 are group 1 s-block elements)

Quaternary reciprocal systems of alkali metal fluorides, chlorides, and bromides were partitioned into simplexes by a geometric method and a graph method. Phase transformations and chemical reactions in the bordering ternary reciprocal systems were described. Conversion lines were experimentally studied, and information on crystallizing phases within the composition prisms of the M₁,M₂‖F,Cl,Br systems (M₁ and M₂ are group 1 s-block elements) was obtained.     

Phase equilibria in the ternary reciprocal system Li,Rb‖F,CrO4

The ternary reciprocal system of fluorides and chromates of lithium and rubidium was studied for the first time. The stable pair of salts LiF and Rb₂CrO₄ and also binary compounds on the bordering sides partition the system into five simplexes. Studying a number of polythermal sections allowed us to determine the melting points and compositions of two peritectics and three eutectics. The crystallization fields of phases in the system were demarcated, and phase equilibria were described.     

Phase complex of the Li,K,Ba‖F,Br quaternary reciprocal system

The partition of the Li,K,Ba??F,Br quaternary reciprocal system into simplexes was performed and confirmed by X-ray powder diffraction. Internal partitioning elements, LiF-2KBr · BaBr₂ and KBr-LiF · BaF₂, were identified; the tree of phases forms two cycles. Simplexes involving phase separation were determined. The stable partitioning triangles LiF-KBr-BaBr₂ and LiF-KBr-BaF₂ · BaBr₂ were experimentally studied by differential thermal and X-ray powder diffraction analyses. The T-x diagrams of explored sections and the liquidi of the systems were constructed. Phase separation regions within the systems under investigations were delimited. The characteristics of alloys corresponding to invariant compositions were determined.     

Li, K‖Br, VO3 ternary mutual system

Phase equilibria in the Li, K‖Br, VO₃ ternary mutual system were studied by differential thermal analysis. The composition square of the ternary mutual system is divided into two phase triangles, LiVO₃-KBr-KVO₃ and LiBr-LiVO₃-KBr. The ternary eutectics E ₁ at 331°C and E ₂ at 330°C have the compositions 40.0 mol % LiVO₃, 6.0 mol % KBr, 54.0 mol % KVO₃ and 58.0 mol % LiBr, 3.2 mol % LiVO₃, 38.8 mol % KBr, respectively. The fields of phases crystallizing in the system were delimited.     

Interaction of salts in ionic melts of the ternary reciprocal systems Na,K‖BO2,MoO4 and Na,K‖BO2,WO4

The phase diagrams of the ternary reciprocal systems Na,K‖BO₂,MoO₄ and Na,K‖BO₂,WO₄ were studied for the first time by a calculation-experimental method and differential thermal analysis. The coordinates were determined for binary eutectics of the diagonal stable sections NaBO₂-K₂MoO₄(K₂WO₄) and the ternary invariant points e(55 mol % NaBO₂, 45 mol % K₂MoO₄, 740°C), e(55 mol % NaBO₂, 45 mol % K₂WO₄, 730°C), E(4.5 mol % NaBO₂, 78 mol % Na₂MoO₄, 17.5 mol % K₂MoO₄, 652°C), E(4.5 mol % NaBO₂, 78 mol % Na₂WO₄, 17.5 mol % K₂WO₄, 643°C), P₂(5 mol % NaBO₂, 56 mol % Na₂MoO₄, 39 mol % K₂MoO₄, 673°C), P₂(5 mol % NaBO₂, 56 mol % Na₂WO₄, 39 mol % K₂WO₄, 671°C). Binary solid solutions based on sodium and potassium metaborates were shown to be stable. Analytical models of phase equilibrium states of the ternary reciprocal systems Na,K‖BO₂,MoO₄(WO₄) were obtained, which enable one to calculate melting (crystallization) points and construct isotherms at any given composition. The specific heats of melting of samples of invariant compositions were found by quantitative differential thermal analysis.     

Quaternary reciprocal system Li,K‖F,Br,NO<Subscript>3</Subscript>

The quaternary reciprocal system Li,K‖F,Br,NO₃ was described and studied for the first time. The system was partitioned into simplexes by writing an adjacency matrix and solving a logical expression. The partition was confirmed by the results of differential scanning calorimetry of two partitioning triangles (LiF-KBr-KNO₃ and LiF-KBr-LiNO₃) and three stable triangles (LiBr-LiF-KBr-LiNO₃, LiNO₃-LiF-KNO₃-KBr, and KF-LiF-KNO₃-KBr). The compositions (mol %) and melting points of quaternary eutectics of the system Li,K‖F,Br,NO₃ were determined: E ₁ ^□ (4.0% LiF, 48.0% LiNO₃, 17.28% KBr, 30.7% LiBr, T _melt = 186°C), E ₂ ^□ (7.35% LiF, 47.53% KNO₃, 2.0% KBr, 43.12% LiNO₃, T _melt = 102°C), and E ₃ ^□ (2.0% LiF, 84.28% KNO₃, 0.98% KBr, 12.74% KF, T _melt = 280°C).     

K,Cs∥F,I and Rb,Cs∥F,I three-component reciprocal systems

The K,Cs∥F,I and Rb,Cs∥F,I three-component reciprocal systems are studied by thermal analysis and X-ray powder diffraction. In the K,Cs∥F,I system, two ternary eutectics are formed; in the Rb,Cs∥F,I system, there are two fields of continuous solid solutions, one formed by rubidium and cesium fluorides and the other by rubidium and cesium iodides.     

Partition of the Li,K‖F,Cl,Br quaternary reciprocal system into simplexes and investigation of components of the LiF-KCl-KBr stable triangle

A quaternary reciprocal system of fluorides, chlorides, and bromides of lithium and potassium was partitioned into simplexes by a geometric method and by a graph method. Phase transformations and chemical reactions in the boundary ternary reciprocal systems were described. A conversion line was experimentally studied, and information on crystallizing phases within the composition prism of the Li,K‖F,Cl,Br system was obtained and confirmed by X-ray powder diffraction data. An immiscibility region in the LiF-KCl-KBr stable triangle was outlined.     

Chemical interaction in the quaternary mutual systems Li,K‖F,Cl,MoO4 and Li,K‖F(Cl),VO3,MoO4

The Li,K‖Cl,VO₃,MoO₄ system was partitioned into simplexes using graph theory, and the tree of phases for this system was constructed. The equations of the main reactions describing the chemical interaction in the quaternary mutual systems Li,K‖F,Cl,VO₃(MoO₄) and Li,K‖F(Cl),VO₃,MoO₄ were derived using the conversion patterns of partitioning elements. Based on the reaction equations and the data on the boundary elements, the prediction of phases crystallizing in the studied systems was made and confirmed by X-ray powder diffraction analysis.     

Stable tetrahedron LiF-KCl-KBr-K2MoO4 of the quinary reciprocal system Li,K‖F,Cl,Br,MoO4

The stable tetrahedron LiF-KCl-KBr-K₂MoO₄ of the quinary reciprocal system Li,K‖F,Cl,Br,MoO₄ was studied by differential thermal analysis, and phase equilibria were determined.     

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.     

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.     

Determination of low-melting alloys in the ternary reciprocal system Na,K‖Br,WO<Subscript>4</Subscript>

The ternary reciprocal system Na,K‖Br,WO₄ was studied by differential thermal analysis. The compositions and melting points of the alloys corresponding to invariant equilibrium points were determined, and the enthalpies of melting of eutectic mixtures were measured. Phase equilibria in systems were described, and the fields of crystallizing phases were delineated.     

New Zn(Ⅱ)/M(Ⅰ)(M=Na,K and Rb) Metal-organic Frameworks Based on 5-Methylisophthalic Acid Ligand:Syntheses,Structures and Fluorescent Property

Reactions of Zn(NO3)2·6H2O and MNO3(M = Na, K and Rb) with H2mip(H2mip = 5-methylisophthalic acid) in DMF(DMF = N,N′-dimethylformamide) resulted in the formation of novel heterometallic metal-organic frameworks(Me2NH2)[ZnM(mip)2](1: M = Na; 2: M = K; 3: M = Rb, mip = 5-methylisophthalate dianion for 1~3). These complexes belong to the monoclinic system, space group P2/c and have been fully characterized by satisfactory elemental analysis, FT-IR spectra, TGA and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies reveal that 1~3 are 3D isomorphic structures based on a trinuclear unit {ZnM2(?2-COO)2(?3-COO)2} and exhibit pcu topological net and blue fluorescence.     

121,123Sb NQR study of solid phases formed in systems (MF)1−x −(M′F) x −SbF3−H2O (M, M′=Na, K, Rb, Cs, and NH4)

Crystalline substances formed in the (MF)_1−x −(M′F) _x −SbF₃−H₂O systems (M, M′=Na, K, Rb, Cs, and NH₄;x=0 to 1) were investigated by^121,123Sb NQR spectroscopy at 77 K. The formation of individual Sb^III complexes NaCs₃Sb₄F₁₆·H₂O and NaKSbF₅·1.5H₂O, and statistically disordered mixed crystals M_1−x −M′ _x −SbF₄ (M, M′=K, Rb, Cs, and NH₄) was established. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 109–112, January, 1999.     

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.

     

New Zn（Ⅱ）/M（I） （M = Na,K and Rb） Metal-organic Frameworks Based on 5-Methylisophthalic Acid Ligand： Syntheses,Structures and Fluorescent Property

Reactions of Zn（NO3）E＇6H20 and MNO3 （M = Na, K and Rb） with HEmip （HEmip = 5-methylisophthalic acid） in DMF （DMF = N,N＇-dimethylformamide） resulted in the formation of novel heterometallic metal-organic frameworks （MeENHE）[ZnM（mip）2] （1： M = Na; 2： M = K; 3： M = Rb, mip = 5-methylisophthalate dianion for 1-3）. These complexes belong to the monoclinic system, space group PE/c and have been fully characterized by satisfactory elemental analysis, FT-IR spectra, TGA and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies reveal that 1-3 are 3D isomorphic structures based on a trinuclear unit {ZD.ME（/d2-COO）E（μ3- COO）E} and exhibitpcu topological net and blue fluorescence.