Phase diagrams of the systems Sc<Subscript>2</Subscript>S<Subscript>3</Subscript>-Ln<Subscript>2</Subscript>S<Subscript>3</Subscript> for Ln = La,Nd, or Gd

Phase diagrams have been designed for the systems Sc₂S₃-Ln₂S₃ where Ln = La, Nd, or Gd. In these systems, complex sulfides crystallize in orthorhombic space group Pnma. The sulfides melt congruently and have the following parameters; for LaScS₃, a = 0.718 nm, b = 0.654 nm, c = 0.960 nm, 2000 K, 3200 MPa; for NdScS₃, a = 0.712 nm, b = 0.646 nm, c = 0.952 nm, 1960 K, 3500 MPa; and for GdScS₃, a = 0.704 nm, b = 0.640 nm, c = 0.946 nm, 1900 K, 3400 MPa. The extents of the solid solutions based on the existing phases increase as the effective ion radii of Ln³⁺ approaches that of Sc³⁺. At 1670 K, the LnScS₃ homogeneity region is 48–52 mol % Nd₂S₃ and 46–54 mol % Gd₂S₃. Sc₂S₃ dissolves 3 mol % Nd₂S₃ and 6 mol % Gd₂S₃. γ-Nd₂S₃ dissolves 2 mol % Sc₂S₃, and γ-Gd₂S₃ dissolves 4 mol % Sc₂S₃. The subsystems Sc₂S₃-LnScS₃ and LnScS₃-Ln₂S₃ are of the eutectic type. The eutectic coordinates are, respectively, 27 mol % La₂S₃, 1880 K; 75 mol % La₂S₃, 1800 K; 30 mol % Nd₂S₃, 1850 K; 74 mol % Nd₂S₃, 1770 K; 33 mol % Gd₂S₃, 1800 K; and 74 mol % Gd₂S₃, 1730 K.     

Phase equilibria in the systems SrS-Cu<Subscript>2</Subscript>S-Ln<Subscript>2</Subscript>S<Subscript>3</Subscript> (Ln = La or Nd)

Phase equilibria in the systems SrS-Cu₂S-Ln₂S₃ (Ln = La or Nd) have been studied along the isothermal section at 1050 K and vertical sections CuLnS₂-SrS and Cu₂S-SrLnCuS₃, which are partially quasibinary joins. Compounds SrLnCuS₃ with Ln = La or Nd have been synthesized for the first time. They crystallize in orthorhombic space group Pnma, the BaLaCuS₃ structure type, with the following unit cell parameters: for SrLaCuS₃, a = 1.1157(2) nm, b = 0.41003(6) nm, c = 1.1545(2) nm; for SrNdCuS₃, a = 1.1083(1) nm, b = 0.40887(7) nm, c = 1.1477(2) nm. Noticeable homogeneity regions for SrLnCuS₃ are not found. The compounds melt congruently by the reaction SrLnCuS₃ ? SrS + L at 1365 K for SrLaCuS₃ and 1400 K for SrNdCuS₃. The tie-lines at 1050 K in the systems SrS-Cu₂S-Ln₂S₃ radiate from SrLnCuS₃ toward phases SrS, Cu₂S, CuLnS₂, and SrLn₂S₄, lying between the phases CuLnS₂ and compositions from the γ-Ln₂S₃-SrLn₂S₄ solid-solution field. Eutectics are formed between the compounds CuLaS₂ and SrLaCuS₃ at 21.0 mol % SrS, T = 1345 K; between the compounds CuNdS₂ and SrNdCuS₃ at 31.0 mol % SrS, T = 1310 K; and between the phases Cu₂S and SrLnCuS₃ at 14.0 mol % SrLaCuS₃, T = 1075 K and 8.0 mol % SrNdCuS₃, T = 1055 K.     

Phase equilibria in the BaS-Cu<Subscript>2</Subscript>S-Gd<Subscript>2</Subscript>S<Subscript>3</Subscript> system

Phase equilibria in the BaS-Cu₂S-Gd₂S₃ system have been studied along the 800 K isothermal section and the CuGdS₂-BaS, Cu₂S-BaGdCuS₃, BaGdCuS₃-Gd₂S₃, and BaGdCuS₃-BaGd₂S₄ polythermal sections. Complex sulfide BaGdCuS₃ is formed in the title system; it has an orthorhombic KZrCuSe₃-type structure (space group Cmcm) with the unit cell parameters equal to a = 0.40529(2) nm, b = 1.34831(6) nm, c = 1.02940(5) nm. This sulfide melts congruently at 1685 K. BaGdCuS₃ is in equilibrium with sulfides Cu₂S, BaS, Gd₂S₃, CuGdS₂, BaGd₂S₄, BaCu₄S₃, and BaCu₂S₂ and with compositions in the C₀ solid-solution region of the Cu₂S-Gd₂S₃ system. Eutectics are formed between compounds CuGdS₂ and BaGdCuS₃ at 7.0 mol % BaS and T = 1325 K, between BaGdCuS₃ and BaS at 64.0 mol % BaS and T = 1625 K, between Cu₂S and BaGdCuS₃ at 8.0 mol % BaGdCuS₃ and T = 1125 K, between Gd₂S₃ and BaGdCuS₃ at 64.0 mol % Gd₂S₃ and 1495 K, and between BaGdCuS₃ and BaGd₂S₄ at 35 mol % BaGd₂S₄ and T = 1660 K.     

Synthesis and crystal structure of a novel two-dimensional network complex [Mn(O<Subscript>2</Subscript>CCH<Subscript>2</Subscript>Cl)<Subscript>2</Subscript>(phen)]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

A novel two-dimensional network manganese(II) polymer complex [Mn(O₂CCH₂CI)₂-(phen)] _n has been synthesized and characterized by elemental analysis and IR spectrum. The crystal structure of title complex has also been determined, which is in monoclinic of a space group P2₁/c with the following unit cell parameters at 294K:a =1.9738 (4) nm,b=1.1384 (2) nm,c =0.74915(14) nm,V = 1.6795(5) nm³, Z= 2.     

Crystal Structure of New One-Dimensional Triple Molybdate Na<Subscript>2</Subscript>K<Subscript>2</Subscript>Cu(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript>

The title compound (disodium dipotassium copper(II) tris-[molybdate (VI)]) is prepared by form melt and characterized by single crystal X-ray diffraction and UV-vis spectroscopy. It crystallizes in the triclinic space group P-1 with a = 7.4946(8) Å, b = 9.3428(9) Å, c = 9.3619(9) Å, α = 92.591(7)°, β = 105.247(9)°, γ = 105.496(9)°, V = 604.7 ų, and Z = 2. Its structure is isotypic with that of Na₄Mn(MoO₄)₃. It is formed by Cu₂O₁₀ distorted bi-octahedral dimers linked by two bridging bidentate Mo₂O₄ tetrahedra and, additionally, two monodentate Mo₁O₄ tetrahedra to form Cu₂Mo₄O₂₀ units. These units are linked by the insertion of Mo₃O₄ tetrahedra to build infinite ribbons disposed along the c axis. All of these ribbons form a one-dimensional framework. Both K1 and K3 cations are located in the inversion center, and all the other atoms are at general positions. The structure model is supported by the bond valence sum (BVS) and charge distribution CHARDI methods. The Cu²⁺ cations adopt the [4+2] CuO₆ Jahn-Teller distortion giving rise to an intense d–d transition in the UV-vis absorption spectra.     

Synthesis and Physicochemical Properties of a Lanthanum-Containing Analog of the Mineral Berthierite FeSb<Subscript>2</Subscript>S<Subscript>4</Subscript>

Phase equilibria in the FeSb₂S₄–FeLa₂S₄ system were studied by physicochemical analysis methods (differential thermal, X-ray powder diffraction, and microstructural analyses and microhardness and density measurements), and the phase diagram of the system was constructed. The formation of quaternary sulfide FeLaSbS₄ melting congruently at 1230 K, an analog of the mineral berthierite FeSb₂S₄, was detected. The X-ray powder diffraction analysis showed that FeLaSbS₄ belongs to the berthierite structural type and crystallizes in the orthorhombic system with the unit cell parameters a = 11.424 Å, b = 14.160 Å, c = 3.782 Å, Z = 4, and space group Pbam.     

Crystal structures of <Emphasis Type="Italic">trans</Emphasis>-[Re<Subscript>6</Subscript>S<Subscript>8</Subscript>(CN)<Subscript>2</Subscript>L<Subscript>4</Subscript>] complexes,L = pyridine or 4-methylpyridine

The structures of three novel octahedral rhenium cluster compounds [Re₆S₈(CN)₂(py)₄]·H₂O (1), [Re₆S₈(CN)₂(4-Mepy)₄] (2), [Re₆S₈(CN)₂(4-Mepy)₄]·4-Mepy (3) (py = pyridine, 4-Mepy = 4-methylpyridine) are determined by X-ray crystallography. Crystal data are: C2/m space group, a = 14.813(1) Å, b = 14.772(1) Å, c = 9.2122(6) Å, β = 119.085(2)°, V = 1761.7(2) ų, d _x = 3.318 g/cm³, R = 0.0585 (1); I4₁/amd space group, a = 16.0018(3) Å, c = 14.7186(5) Å, V = 3768.81(16) ų, d _x = 3.169 g/cm³, R = 0.0489 (2); P2₁/c space group, a = 9.0452(4) Å, b = 15.8065(7) Å, c = 15.2951(6) Å, β = 103.700(2)°, V = 2124.57(16) ų, d _x = 2.957 g/cm³, R = 0.0245 (3). Molecular cluster complexes interact via π-π stacking affording 3D frameworks in 1 and 2 and chains in 3.     

High-pressure nonstoichiometric phase Sm<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Cu<Subscript>3</Subscript>V<Subscript>4</Subscript>O<Subscript>12</Subscript>

Perovskite-like nonstoichiometric oxide Sm _x Cu₃V₄O₁₂ (space group Im \(\bar 3\), Z = 2, a = 7.276?7.314 Å) with cationic vacancies and a homogeneity region was prepared barothermally (p = 6.0?9.0 GPa, T = 700?1100°C) for the first time. Structural and isotropic thermal parameters, as well as bond lengths and bond angles, were determined. The compound has metal-type conductivity and paramagnetic properties.     

Phase equilibria in the Tl-TlCl-Te system and thermodynamic properties of the compound Tl<Subscript>5</Subscript>Te<Subscript>2</Subscript>Cl

The Tl-Te-Cl system was studied in the Tl-TlCl-Te composition region by differential thermal analysis, X-ray powder diffraction, and emf and microhardness measurements. A series of polythermal sections, an isothermal section at 400 K, and a projection of the liquidus surface of the phase diagram were constructed. The ternary compound Tl₅Te₂Cl characterized by a wide homogeneity region and incongruent melting by a syntectic reaction at 708 K was shown to exist. This compound was found to crystallize in tetragonal lattice (space group I4/mcm) with the parameters a = 8.921 Å, c = 12.692 Å, Z = 4. Wide phase separation regions were also found in the system, including a three-phase separation region in the Tl-TlCl-Tl₂Te subsystem. Regions of primary crystallization of phases, and the types and coordinates of in- and monovariant equilibria in the T-x-y diagram were determined. From emf measurement data, the standard thermodynamic functions of formation and the standard entropy were calculated for the compound Tl₅Te₂Cl, as follows: ?ΔG ₂₉₈ ⁰ = 355.9 ± 1.1 kJ/mol, ?ΔH ₂₉₈ ⁰ = 377.1 ± 5.0 kJ/mol, and S ₂₉₈ ⁰ = 474.1 ± 6.8 J/(mol K).     

Structural investigation of [Au(en)<Subscript>2</Subscript>]Cl(ReO<Subscript>4</Subscript>)<Subscript>2</Subscript> and [Au(en)<Subscript>2</Subscript>](ReO<Subscript>4</Subscript>)<Subscript>3</Subscript> complexes

Novel complex salts [Au(en)₂]Cl(ReO₄)₂ (I) and [Au(en)₂](ReO₄)₃ (II), en = ethylenediamine, are obtained. Their crystal structures are determined by single crystal X-ray diffraction. Complex I crystallizes in the triclinic crystal system: a = 6.2172(7) Å, b = 7.1644(8) Å, c = 8.8829(8) Å, α = 96.605(4)°, β = 110.000(4)°, γ = 97.802(4)°, P-1 space group, Z = 1, d _x = 3.905 g/cm³; complex II crystallizes in the monoclinic crystal system: a = 15.244(2) Å, b = 7.6809(8) Å, c = 9.3476(12) Å, β = 127.004(3)°, C2 space group, Z = 4, d _x = 4.057 g/cm³.     

Phase formation in the BaB<Subscript>2</Subscript>O<Subscript>4</Subscript>-NaBO<Subscript>2</Subscript>-MBO<Subscript>3</Subscript> (M = Sc,La, Y) system and new orthoborate ScBaNa(BO<Subscript>3</Subscript>)<Subscript>2</Subscript>

Phase formation in the BaB₂O₄-NaBO₂-MBO₃ (M = Sc, La, Y) system was studied using solid-phase synthesis, visual polythermal analysis, and spontaneous crystallization. This system was shown to be suitable for growing LaBO₃. A new compound, ScBaNa(BO₃)₂, was obtained (trigonal crystal system; space group R \(\bar 3\) unit cell parameters: a = 5.239(1) Å, c = 34.591(1) Å, and V = 822.38(4) ų).     

Synthesis and X-ray investigation of Rb<Subscript>2</Subscript>[Pd(NO<Subscript>3</Subscript>)<Subscript>4</Subscript>] and Cs<Subscript>2</Subscript>[Pd(NO<Subscript>3</Subscript>)<Subscript>4</Subscript>]

Powder and single crystal X-ray diffraction studies have been performed for anhydrous nitrate complexes Rb₂[Pd(NO₃)₄] (I) and Cs₂[Pd(NO₃)₄] (II). Crystal data for I: a = 7.843(1) Å, b = 7.970(1) Å, c = 9.725(1) Å; β = 100.39(1)°, V = 597.9(1) Å ³, space group P2₁/c, Z = 2, d _calc = 2.918 g/cm³; for II: a = 10.309(2) Å, b = 10.426(2) Å, c = 11.839(2) Å; β = 108.17(3)°, V = 1209.0(4) ų, space group P2₁/c, Z = 4, d ^calc = 3.408 g/cm³. The structures are formed by isolated [Pd(NO₃)₄]^2? complex anions and alkali metal cations. The plane-square environment of the Pd atom is formed from the oxygen atoms of the monodentate nitrate groups. The geometrical characteristics of the complex anions are analyzed. Compound II has a short contact Pd...Cs 3.252 Å.     

Chromites YbMCr<Subscript>2</Subscript>O<Subscript>5</Subscript> (M = Li,Na, K,Cs): X-ray diffraction study

Ytterbium alkali-metal chromites YbMCr₂O₅ (M = Li, Na, K, Cs) were synthesized by a ceramic procedure from the corresponding oxides and carbonates. Their crystal systems and unit cell parameters were determined by the homology method: for YbLiCr₂O₅, a = 10.34 Å, b = 10.62 Å, c = 15.05 Å, Z = 16, V ^o = 1653.74 ų, ρ_X-ray = 5.85 g/cm³, ρ_pycn = 5.81 ± 0.03 g/cm³; for YbNaCr₂O₅, a = 10.30 Å, b = 10.56 Å, c = 16.46 Å, Z = 16, V ^o = 1790.32 ų, ρ_X-ray = 5.64 g/cm³, ρ_pycn = 5.59 ± 0.07 g/cm³; for YbKCr₂O₅, a = 10.33 Å, b = 10.63 Å, c = 19.93 Å, Z = 16, V ^o = 2188.47 ų, ρ_X-ray = 5.95 g/cm³, ρ_pycn = 5.91 ± 0.03 g/cm³; and for YbCsCr₂O₅, a = 10.34 Å, b = 10.63 Å, c = 18.43 Å, Z = 16, V ^o = 2025.72 ų, ρ_X-ray = 5.19 g/cm³, ρ_pycn = 5.16 ± 0.05 g/cm³.     

Crystal structures of Ti(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript> and Sn(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript>

The characteristics of crystal structures of the titanium(IV) diammonium (Ti(NH₄)₂P₄O₁₃) and tin(IV) diammonium (Sn(NH₄)₂P₄O₁₃) tetraphosphates, which are isostructural with similar silicon(IV) and germanium(IV) salts, have been obtained by the Rietveld method using X-ray powder diffraction data. The compounds crystallize in the triclinic system, space group P \(\overline 1 \), Z = 2, a = 15.0291(7) Å, b = 7.9236(4) Å, c = 5.0754(3) Å, α = 99.168(3)°, β = 97.059(3)°, γ = 83.459(3)° for Ti(NH₄)₂P₄O₁₃ and a = 15.1454(7) Å, b = 8.0103(5) Å, c = 5.1053(3) Å, α = 99.898(6)°, β = 96.806(3)°, γ = 83.881(4)° for Sn(NH₄)₂P₄O₁₃. The structure is refined in the isotropic approximation using the pseudo-Voigt function: R _p = 0.077, R _Bragg = 0.045, R _F = 0.057 for Ti(NH₄)₂P₄O₁₃; R _p = 0.082, R _Bragg = 0.044, R _F = 0.046 for Sn(NH₄)₂P₄O₁₃. The hydrogen atoms of the ammonium cations are placed in the calculated positions. A comparative analysis of the structures of the compounds of the M^IV(NH₄)₂P₄O₁₃ (M^IV = Si, Ge, Ti, Sn) series has been carried out.     

Phase equilibria in the BaS–Ga<Subscript>2</Subscript>S<Subscript>3</Subscript> system

In the BaS–Ga₂S₃ system, the following compounds form: congruently melting compound BaGa₄S₇ (rhombic system, space group Pmn2₁, a = 1.477 nm, b = 0.624 nm, c = 0.593 nm, and T_melt = 1490 K) and incongruently melting compounds BaGa₂S₄ (cubic system, space group Pa3, a = 1.2661 nm, and Tmelt = 1370 K), Ba₂Ga₂S₅ (monoclinic system, space group C2/c, a = 1.529, b = 1.479, c = 0.858 nm, ß = 106.04°, and T_melt = 1150 K), Ba₃Ga₂S₆ (monoclinic system, space group C2/c, a = 0.909 nm, b = 1.448 nm, c = 0.903 nm, ß = 91.81°, and T_melt = 1190 K), Ba₄Ga₂S₇ (monoclinic system, space group P2₁/m, a = 1.177 nm, b = 0.716 nm, c = 0.903 nm, ß = 108.32°, and T_melt = 1230 K), and Ba₅Ga₂S₈ (rhombic system, space group Cmca, a = 2.249 nm, b = 1.215 nm, c = 1.189 nm, and T_melt = 1480 K). The compositions of eutectics are 38 and 72 mol % Ga₂S₃, and their melting points are 1120 and 1160 K, respectively. The BaS solubility in γ-Ga₂S₃ at 1070 K reaches 3 mol %.     

Low-temperature heat capacity and high-temperature thermal behavior of sodium lutetium molybdate phosphate Na<Subscript>2</Subscript>Lu(MoO<Subscript>4</Subscript>)(PO<Subscript>4</Subscript>)

The low-temperature heat capacity of Na₂Lu (MoO₄)(PO₄) was measured by adiabatic calorimetry in the range of 7.47–345.74 K. The experimental data were used to calculate the thermodynamic functions of Na₂Lu (MoO₄)(PO₄). At 298.15 K, the following values were obtained: C _p ⁰ (298.15 K) = 237.7 ± 0.1 J/(K mol), S ⁰(298.15 K) = 278.1 ± 0.8 J/(K mol), H ⁰(298.15 K) ? H ⁰ (0 K) = 42330 ± 20 J/mol, and Φ⁰(298.15 K) = 136.1 ± 0. 3 J/(K mol). A heat capacity anomaly was found in the range of 10-67 K with a maximum at T _tr = 39.18 K. The entropy and enthalpy of transition are ΔS = 12.39 ± 0.75 J/(K mol) and ΔH = 403 ± 16 J/mol. The thermal investigation of sodium lutetium molybdate phosphate in the high-temperature range (623–1223 K) was performed using differential scanning calorimetry. It was found that during melting in the range of 1030–1200 K, Na₂Lu(MoO₄)(PO₄) degrades to simpler compounds; the degradation scenario is verified by X-ray powder diffraction.     

Crystal structure of KPb<Subscript>2</Subscript>Cl<Subscript>5</Subscript> and KPb<Subscript>2</Subscript>Br<Subscript>5</Subscript>

The KPb₂Cl₅ and KPb₂Br₅ crystals are monoclinic (P2₁/c) with a microtwinned structure. X-ray analysis of chloride resulted in the parameters a = 8.854(2) Å, b = 7.927(2) Å, c = 12.485(3) Å; β = 90.05(3)°, d_calc = 4.78(1) g/cm³ (STOE STADI4, MoK_α, 2θ_max = 80°), R₁ = 0.0702 for 4094 F ≥ 4 σ(F) reflections. For bromide, a = 9.256(2) Å, b = 8.365(2) Å, c = 13.025(3) Å; β = 90.00(3)°, d_calc = 5.62(1) g/cm³ (Bruker P4, MoK_α, 2θ_max = 70°), R₁ = 0.0692 for 3076 F ≥ 4 (F) reflections.     

Synthesis,structure, and properties of V<Subscript>2</Subscript>O<Subscript>3</Subscript>(XO<Subscript>4</Subscript>)<Subscript>2</Subscript> (X = S,Se)

Compounds described as V₂O₃(XO₄)₂, where X = S or Se, were prepared from vanadium(V) oxide mixtures with concentrated sulfuric and selenic acids. The physicochemical properties of the products were studied; for V₂O₃(SeO₄)₂, the crystal structure was determined by powder X-ray diffraction and neutron diffraction, and its key differences from the structure of V₂O₃(SO₄)₂ were identified. V₂O₃(SeO₄)₂ crystallizes in the monoclinic system with the unit cell parameters a = 15.3831(2)Å, b = 5.54096(5)Å, c = 9.71644(7)Å, β = 111.886(1)°, V = 768.51ų, space group C2/c (no. 15).     

Structural analysis of modulated crystals. A new structure of Ce<Subscript>4</Subscript>Pd<Subscript>13.6</Subscript>Sn<Subscript>5.9</Subscript>

Incommensurate modulated structure of Ce₄Pd_13,6Sn_5,9 intermetallic is studied by (3+1)D analysis in a rhombic basic cell a = 2.08458(4) nm, b = 0.47129(1) nm, and c = 0.92874(1) nm; q = 0,2407(1)b*. Xmmm(0β0)000 group determines the symmetry of the crystal. The superspace analysis is compared to the analysis of the superstructure with a, 4b, and c periods in three dimensions.     

Synthesis and magnetic properties of quasi-unidimensional oxide Sr<Subscript>6.3</Subscript>Rh<Subscript>2.35</Subscript>Mn<Subscript>2.35</Subscript>O<Subscript>15</Subscript>

Attempts of the synthesis in air of complex oxides Sr₃RhMnO_x and Sr₄Rh_1.5Mn_1.5O_x resulted in revealing formation of a new oxide phase Sr_6.3Rh_2.35Mn_2.35O₉ related to quasi-unidimensional family A_3n+3m A′ _n B_3m+n O_9m+6n at n = 1 and m = 1. Its structural characteristics and magnetic properties are studied. X-ray data of the obtained phase is indicated on the basis of trigonal cell (spatial group P321) with the parameters: a 9.6239(4) Å; c ₁ 4.1130(4) Å, c ₂ 2.4946(2) Å. Manganese and rhodium exist in the compound as the cations Mn⁴⁺, Rh³⁺ and Rh⁴⁺, as follows from the data of measuring of magnetic susceptibility in the range 2–300 K.