The LiF-LiCl-Li2SO4-Li2MoO4 quaternary system

Phase equilibria in the LiF-LiCl-Li₂SO₄-Li₂MoO₄ quaternary system have been investigated by differential thermal analysis. The eutectic composition (in mol %) has been determined as LiF, 16.2; LiCl, 51.5; Li₂SO₄, 16.2; and Li₂MoO₄, 16.2. The melting point of the eutectic is 402°C, and the enthalpy of melting is 291 J/g.     

LiF-LiVO3-Li2SO4-Li2MoO4 four-component system

The LiF-LiVO₃-Li₂SO₄-Li₂MoO₄ four-component system was studied using differential thermal analysis. The eutectic composition was determined (mol %): LiF, 25.0; LiVO₃, 43.8; Li₂SO₄, 14.8; Li₂MoO₄, 16.5. The eutectic melting point is 428°C; the enthalpy of melting is 260 J/g.     

LiF-LiBr-LiVO3-Li2MoO4-Li2SO4 quinary system

Phase equilibria in the LiF-LiBr-LiVO₃-Li₂MoO₄-Li₂SO₄ quinary system were studied by differential thermal analysis. A eutectic composition was determined to be 4.0 mol % LiF, 38.4 mol % LiBr, 30.8 mol % LiVO₃, 19.2 mol % Li₂MoO₄, and 7.6 mol % Li₂SO₄ with a melting point of 372°C and an enthalpy of melting of 164 ± 7 kJ/kg.     

LiF-LiCl-LiBr-Li2MoO4 quaternary system

Phase equilibria in the LiF-LiCl-LiBr-Li₂MoO₄ quaternary system were studied by differential thermal analysis. The composition of an eutectic was determined to be 20.0 mol % LiF, 27.3 mol % LiCl, 43.1 mol % LiBr, and 9.6 mol % Li₂MoO₄, with the melting point being 424°C.     

Ternary systems LiBr-Li2MoO4-Li2WO4 and LiF-Li2MoO4-Li2WO4

The ternary systems LiBr-Li₂MoO₄-Li₂WO₄ and LiF-Li₂MoO₄-Li₂WO₄ were studied by differential thermal analysis. The fields of crystallizing phases are delimited, and di- and monovariant equilibria for surfaces and monovariant curves are described.     

Phase equilibria in the KCl-KBO2-K2CO3-K2MoO4 quaternary system

The phase diagram of the quaternary system KCl-KBO₂-K₂CO₃-K₂MoO₄ was studied by a calculation-experimental method and differential thermal analysis. Analytical models of phase equilibrium states were obtained, and the coordinates of a quaternary eutectic were determined: 550°C, 50% KCl, 8% KBO₂, 23% K₂CO₃, and 19% K₂MoO₄.     

Phase formation in the Ag2MoO4-CoMoO4-Al2(MoO4)3 system

The subsolidus region of the Ag₂MoO₄-CoMoO₄-Al₂(MoO₄)₃ ternary salt system was studied by X-ray powder diffraction analysis. New compounds Ag_1?x Co_1?x Al_{1 + x} (MoO₄)₃ (0 ≤ x ≤ 0.4) and AgCo₃Al(MoO₄)₅ were detected to form. The variable-composition phase Ag_1?x Co_1?x Al_{1 + x} (MoO₄)₃ is of the NASICON structure type (space group \(R\bar 3c\) ). AgCo₃Al(MoO₄)₅ crystallizes in the triclinic symmetry (space group \(P\bar 1\) Z = 2) with the unit cell parameters a = 6.9101(6), b = 17.519(1), c = 6.8241(6) Å, α = 87.356(7)°, β = 101.078(7)°, and γ = 91.985(9)°. The compounds are thermally stable until 770–780 and 760°C, respectively.     

LiFe(MoO4)2, LiGa(MoO4)2 and Li3Ga(MoO4)3

The structures of lithium iron dimolybdate, LiFe(MoO₄)₂, and lithium gallium dimolybdate, LiGa(MoO₄)₂, are shown to be isomorphous with each other. Their structures consist of segregated layers of LiO₆ bicapped trigonal bipyramids and Fe(Ga)O₆ octahedra separated and linked by layers of isolated MoO₄ tetrahedra. The redetermined structure of trilithium gallium trimolybdate, Li₃Ga(MoO₄)₃, shows substitional disorder on the Li/Ga site and consists of perpendicular chains of LiO₆ trigonal prisms and two types of differently linked Li/GaO₆ octahedra.     

Phase equilibria in the Tl2MoO4-Nd2(MoO4)3-Hf(MoO4)2 system and the crystal structure of double molybdate TlNd(MoO4)2

The Tl₂MoO₄-Nd₂(MoO₄)₃-Hf(MoO₄)₂ system was studied in the subsolidus region using X-ray powder diffraction. New triple molybdates were found to exist in this system: Tl₅NdHf(MoO₄)₆ (5: 1: 2), TlNdHf_0.5(MoO₄)₃ (1: 1: 1), and Tl₂NdHf₂(MoO₄)_6.5 (2: 1: 4). The first TlNd(MoO₄)₂ single crystals were grown from melt solutions with spontaneous nucleation. Their crystal structure was refined from X-ray diffraction data (Bruker X8 Apex automated diffractometer, MoK _α radiation, 386 F(hkl), R = 0.0136). The tetragonal unit cell parameters are as follows: a = 6.3000(2) Å, c = 9.5188(5) Å, V = 377.80(3) ų, Z = 2, ρ_calcd = 5.876 g/cm³, space group P4/nnc. The structure is a framework built of NdO₈ and TlO₈ tetragonal antiprisms linked via shared lateral edges and alternating in the checkerboard order. Layers share oxygen vertices with MoO₄ interlayer tetrahedra and are linked into the framework.     

Phase equilibria in the Tl2MoO4-Fe2(MoO4)3-Hf(MoO4)2 system and the crystal structure of ternary molybdate Tl(FeHf0.5)(MoO4)3

The subsolidus region of the ternary salt system Tl₂MoO₄-Fe₂(MoO₄)₃-Hf(MoO₄)₂ was studied by X-ray powder diffraction. New compounds Tl₅FeHf(MoO₄)₆ (5: 1: 2) and Tl(Fe,Hf_0.5)(MoO₄)₃ (1: 1: 1). were found to be formed in this system. Crystals of new ternary molybdate of the composition Tl(FeHf_0.5)(MoO₄)₃ were grown by spontaneous flux crystallization. Its composition and crystal structure were refined based on X-ray diffraction data. The mixed three-dimensional framework of the crystal structure is composed of Mo tetrahedra sharing O vertices with (Fe,Hf)O₆ octahedra. The thallium atoms occupy wide channels in the framework.     

Studies on the system CrVO4-Fe2(MoO4)3

X-RPD and DTA revealed that CrVO₄ reacts with Fe₂(MoO₄)₃ in the solid state to form Fe₂Cr₂V₂Mo₃O₂₀. The thermal and X-ray characteristics of this phase have been established.

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Zusammenfassung Mittels DTA und Debye-Scherrer-Untersuchungen wurde festgestellt, daß CrVO₄ und Fe₂(MoO₄)₃ im festen Zustand miteinander reagieren und Fe₂Cr₂V₂Mo₃O₂₀ bilden. Thermische und röntgenographische Eigenschaften dieser Phase wurden ermittelt.

     

Phase equilibria in the FeVO4-Fe2(MoO4)3 system

Phase équilibria have been investigated in the FeVO₄-Fe₂(MoO₄)₃ system for the whole concentration range of the components. In this system there is one compound which melts incongruently: Fe₄V₂Mo₃O₂₀. The results are presented in the form of a phase diagram.

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Zusammenfassung Phasengleichgewichte im System FeVO₄-Fe₂(MoO₄)₃ wurden über den ganzen Konzentrationsbereich der Komponenten hinweg untersucht. Eine Verbindung des Systems, Fe₄V₂Mo₃O₂₀, schmilzt inkongruent. Die Ergebnisse sind in Form eines Phasendiagramms angegeben.

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FeVO₄-Fe₂(MoO₄)₃ . Fe₄V₂Mo₃O₂₀, . .

     

Phase formation in the Rb2MoO4-Er2(MoO4)3-Hf(MoO4)2 system and the crystal structure of new triple molybdate Rb5ErHf(MoO4)6

The subsolidus region of the Rb₂MoO₄-Er₂(MoO₄)₃-Hf(MoO₄)₂ ternary salt system is studied using X-ray powder diffraction. A novel 5: 1: 2 triple molybdate, Rb₅ErHf(MoO₄)₆, is found to form in the system. Crystals of Rb₅ErHf(MoO₄)₆ are flux-grown under spontaneous nucleation conditions. The composition and crystal structure of Rb₅ErHf(MoO₄)₆ are refined in a single-crystal X-ray diffraction experiment (X8 APEX diffractometer, MoK _α radiation, 1753 reflections, R = 0.0183). The crystals are trigonal; a = 10.7511(1) Å, c = 38.6543(7) Å, V = 3869.31(9) ų, d _calc = 4.462 g/cm³, Z = 6, space group $R\bar 3c$ . The mixed three-dimensional framework of the structure is formed of MoO₄ tetrahedra, each sharing corners with two ErO₆ and HfO₆ octahedra. Two types of Rb atoms occupy large cavities of the framework. The distribution of the Er³⁺ and Hf⁴⁺ cation over two positions is refined in the course of structure solution.     

Phase equilibrium in the Cs2MoO4-Bi2(MoO4)3-Zn(MoO4)2 system and the crystal structure of new triple molybdate Cs5BiZr(MoO4)6

The subsolidus region of the Cs₂MoO₄-Bi₂(MoO₄)₃-Zr(MoO₄) system was studied by X-ray powder diffraction. Quasi-binary sections were elucidated, and triangulation performed. Triple molybdates with the component ratios 5: 1: 2 (S ₁) and 2: 1: 4 (S ₂) were prepared for the first time. Crystals of cesium bismuth zirconium molybdate of the 5: 1: 2 stoichiometry (Cs₅BiZr(MoO₄)₆) were grown from fluxed melts with spontaneous nucleation. The composition and crystal structure of this triple molybdate were refined using X-ray diffraction data (collected on X8 APEX automated diffractometer, MoK _α radiation, 2348 F(hkl), R = 0.0226). The trigonal unit cell parameters were as follows: a = b = 10.9569(2), c = 39.804(4) Å, V = 4138.4(4) ų, Z = 6, space group R $ \bar 3 The subsolidus region of the Cs₂MoO₄-Bi₂(MoO₄)₃-Zr(MoO₄) system was studied by X-ray powder diffraction. Quasi-binary sections were elucidated, and triangulation performed. Triple molybdates with the component ratios 5: 1: 2 (S ₁) and 2: 1: 4 (S ₂) were prepared for the first time. Crystals of cesium bismuth zirconium molybdate of the 5: 1: 2 stoichiometry (Cs₅BiZr(MoO₄)₆) were grown from fluxed melts with spontaneous nucleation. The composition and crystal structure of this triple molybdate were refined using X-ray diffraction data (collected on X8 APEX automated diffractometer, MoK _α radiation, 2348 F(hkl), R = 0.0226). The trigonal unit cell parameters were as follows: a = b = 10.9569(2), c = 39.804(4) ?, V = 4138.4(4) ?³, Z = 6, space group R c. The mixed-metal three-dimensional framework in this structure is built of Mo tetrahedra and two sorts of (Bi,Zr)O₆ octahedra. Large interstices accommodate two sorts of cesium atoms. The Bi³⁺ and Zr⁴⁺ cation distributions over two positions were refined during structure solution. Original Russian Text ? B.G. Bazarov, T.V. Namsaraeva, R.F. Klevtsova, A.G. Anshits, T.A. Vereshchagina, R.V. Kurbatov, L.A. Glinskaya, K.N. Fedorov, Zh.G. Bazarova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 9, pp. 1585–1589.     

Subsolidus area of the AlVO4−Al2(MoO4)3 system

The behaviour of Al₂(MoO₄)₃ towards AIVO₄ in the subsolidus area, over the whole component concentration range, has been studied using the DTA and XRD methods. The experimental results have been presented in the form of a phase diagram. It has been found that components of the system of interest do not remain in equilibrium, and AlVO₄?Al₂(MoO₄)₃ system is not a real two-component system, even in the subsolidus area.     

Studies on the Fe2(MoO4)3-V2O5 system

The phase equilibria established in solid state in the whole range of component concentrations in the Fe₂(MoO₄)₃-V₂O₅ system were studied by DTA and X-ray powder diffraction. This system is not a real two-component system.

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Zusammenfassung Im gesamten Konzentrationsbereich der Komponenten des Systems Fe₂(MoO₄)₃-V₂O₅ wurde das im festen Aggregatzustand festgestellte Phasengleichgewicht mittels DTA und Pulverröntgendiffraktionsverfahren untersucht. Dieses System ist kein wirkliches Zweikomponentensystem.

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F₂(₄)₃-V₂O₅ . , .

     

LiF-KCl-KVO3-K2MoO4-LiKMoO4 stable pentatope

Phase equilibria in the LiF-KCl-KVO₃-K₂MoO₄-LiKMoO₄ stable pentatope of the Li,K‖F,Cl,VO₃,MoO₄ reciprocal five-component system were studied using differential thermal analysis (DTA). A eutectic was found to have a composition (mol %) of 50.0 LiF, 11.5 KCl, 6.0 KVO₃, 1.6 K₂MoO₄, and 25.0 LiKMoO₄ and a melting temperature of 394°C.     

Investigation par analyse thermique differentielle du systeme Gd2(MoO4)3-Bi2(MoO4)3

The phase diagram of the system Gd₂(MoO₄)₃-Bi(MoO₄)₃ has been studied by differential thermal analysis (DTA). Sealed platinum tubes were used as sample holders, in order to prevent the loss of Bi₂O₃ and MoO₃ through volatilization at high temperature. Various solid solutions and new phases are reported: α-Gd_2-x-Bi_x(MoO₄)₃, β -Gd_2-x-Bi_x(MoO₄)₃, α-Bi_2-xGd_x(MoO₄)₃, 3Gd₂(MoO₄)₃·2Bi₂(MoO₄)₃, etc.     

Phase equilibria in the KCl-KBO2-K2CO3-K2WO4 quaternary system

The phase diagram of the KCl-KBO₂-K₂CO₃-K₂WO₄ quaternary system was studied by a calculation-experimental method and differential thermal analysis. Analytical models of phase equilibrium states were obtained, and the coordinates of a quaternary eutectic were determined: 545°C, 50 mol % KCl, 8 mol % KBO₂, 22.5 mol % K₂CO₃, and 19.5 mol % K₂WO₄.     

Homogeneity regions of double molybdates in the Na2MoO4-MgMoO4 system and structures of triclinic Na1.51Mg2.245(MoO4)3 and Na1.66Mn2.17(MoO4)3

In the samples of the Na₂MoO₄-MgMoO₄ system quenched in the air at above 600°C, by powder X-ray diffraction two double molybdates of variable composition are detected: monoclinic alluaudite-like Na_4?2x Mg_1+x (MoO₄)₃ (0.05 ≤ x ≤ 0.35) and triclinic Na_2?2y Mg_2+y (MoO₄)₃ (0.10 ≤ y ≤ 0.40) isostructural to previously studied Na₂Mg₅(MoO₄)₆. Sodium-magnesium molybdate of the Li₃Fe(MoO₄)₃ structure type is not revealed in this system. By spontaneous flux crystallization, the crystals are obtained and the structures of two triclinic double molybdates of the Na₂Mg₅(MoO₄)₆ structure type (space group $P\bar 1$ , Z = 1) containing magnesium and manganese are determined. The results of the refinement of site occupancies made it possible to determine the composition of the studied crystals: for the compound with magnesium (Na)_0.5(Na_0.255□_0.745)(Na_0.755Mg_0.245)Mg₂(MoO₄)₃ or Na_1.51Mg_2.245(MoO₄)₃ (a = 6.9577(1) Å, b = 8.6330(2) Å, c = 10.2571(2) Å, α = 106.933(1)°, β = 104.864(1)°, γ = 103.453(1)°, R = 0.0188); for the compound with manganese (Na)_0.5(Na_0.33□_0.67)(Na_0.83Mn_0.17)Mn₂(MoO₄)₃ or Na_1.64Mn_2.17(MoO₄)₃ (a = 7.0778(2) Å, b = 8.8115(2) Å, c = 10.4256(2) Å, α = 106.521(1)°, β = 105.639(3)°, Γ = 103.233(1)°, R = 0.0175). The Na₂Mg₅(MoO₄)₆ structure is redetermined and it is shown that actually it corresponds to the composition Na_1.40Mg_2.30(MoO₄)₃.