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.     

Synthesis and x-ray diffraction study of new nanostructured manganite ferrites NdM 1.5 II MnFeO6 (MII = Mg, Ca, Sr, Ba)

Manganite ferrites NdM _1.5 ^II MnFeO₆ (M^II = Mg, Ca, Sr, Ba) were synthesized from neodymium(III), manganese(III), and iron(III) oxides and alkaline-earth metal carbonates by a ceramic technology. By grinding the obtained compounds in a ball mill, their nanostructured particles were produced, the sizes of which were determined with an electron microscope. X-ray diffraction study established that the nanostructured compounds crystallize in the cubic and tetragonal systems with the following lattice parameters: NdMg_1.5MnFeO₆ (tetragonal): a = 10.955 Å, c = 17.848 Å, V ⁰ = 2141.975 ų, Z = 16, V _e1.cel1 ⁰ = 133.873 ų, ρ_X-ray = 4.80 g/cm³, and ρ_pycn = 4.76 ± 0.05 g/cm³; NdCa_1.5MnFeO₆ (cubic): a= 10.809 Å, V ⁰ = 1262.864 ų, Z = 8, V _e1.cel1 ⁰ = 157.858 ų, ρ_X-ray = 4.32 g/cm³, and ρ_pycn = 4.27 ± 0.03 g/cm³; NdSr_1.5MnFeO₆ (cubic): a = 10.911 Å, V ⁰ = 1298.953 ų, Z = 8, V _e1.cel1 ⁰ = 162.369 ų, ρ_X-ray = 4.93 g/cm³, and ρ_pycn= 4.88 ± 0.05 g/cm³; and NdBa_1.5MnFeO₆ (tetragonal): a = 11.011 Å, c = 18.001 Å, V ₀ = 2182.479 ų, Z = 16, V _e1.cel1 ⁰ = 136.405 ų, ρ_X-ray = 6.78 g/cm³, and ρ_pycn= 6.75 ± 0.07 g/cm³.     

Estimating the standard thermodynamic functions of rare-earth and alkali-earth manganitoferrites LnMIIMnFeO5.5 (Ln = La, Nd, Gd, Dy, Er; MII = Mg, Ca, Sr, Ba)

The standard enthalpies of formation of LnM^IIMnFeO^5.5 manganitoferrites (Ln is a rare-earth element, and M^II is an alkali-earth metal) were estimated by the developed method of calculation. Their standard entropies were calculated by the method of ionic increments, and their standard Gibbs energies of formation were determined by the Gibbs-Helmholtz equation.     

X-Ray diffraction data for new ferrites ErMFe<Subscript>2</Subscript>O<Subscript>5</Subscript> (M = Li,Na, K)

New ferrites ErMFe₂O₅ (M = Li, Na, K) were synthesized from erbium and iron(III) oxides and lithium, sodium, and potassium carbonates by solid-state annealing. According to X-ray powder diffraction, these compounds crystallize in the orthorhombic system with the following unit cell parameters: ErLiFe₂O₅, a = 10.510 Å, b = 10.776 Å, c = 14.270 Å, V ⁰ = 1616.16 ų; Z = 16, V _subcell ⁰ = 101.01 ų, ρ_X = 6.01 g/cm³, ρ_pycn = 5.97 ± 0.05 g/cm³; ErNaFe₂O₅, a = 10.519 Å, b = 10.785 Å, c = 15.510 Å, V ⁰ = 1759.56 ų, Z = 16, V _subcell ⁰ = 109.90 ų, ρ_X = 5.77 g/cm³, ρ_pycn = 5.72 ± 0.08 g/cm³; ErKFe₂O₅, a = 10.050 Å, b = 11.320 Å, c = 15.480 Å, V ⁰ = 1937.33 ų, Z = 16, V _subcell ⁰ = 121.08 ų, ρ_X = 5.46 g/cm³, ρ_pycn = 5.41 ± 0.04 g/cm³.     

Synthesis and X-ray diffraction study of the LaMg<Superscript>I</Superscript>Mg(CrO<Subscript>3</Subscript>)<Subscript>2</Subscript> (M<Superscript>I</Superscript> = Li,Na, K) compounds

Ternary chromites of the composition LaM^IMg(CrO₃)₂ (M^I = Li, Na, K) were synthesized for the first time by ceramic technology from stoichiometric amounts of high purity grade La₂O₃; pure for analysis grade Li₂CO₃, Na₂CO₃, K₂CO₃, and MgCO₃; and chemically pure grade Cr₂O₃. Using X-ray diffractometry, it has been established that compounds are crystallized in cubic and tetragonal crystal systems, and parameters of their crystal lattices have been determined.     

Synthesis,Characterization, and Catalytic Properties of Metal-Polymer Complexes Based on Copolymers of Polyethylene(propylene) Glycol Maleates with Acrylic Acid

Russian Journal of Applied Chemistry - New mono- and bimetallic polymer nanocomposites based on polyethylene(propylene) glycol maleates with acrylic acid and silver and nickel metals were prepared...     

X-ray powder diffraction features of manganites DyM 3I M 3II Mn4O12 (MI = Li, Na, K; MII = Mg, Ba)

Manganites DyM₃^IMg₃Mn₄O₁₂ and DyM₃^IBa₃Mn₄O₁₂ (M^I = Li, Na, K) were synthesized by the solid-state reaction of dysprosium and manganese(III) oxides and magnesium and corresponding alkali metal carbonates. The X-ray powder diffraction studies showed that the crystals are orthozhombic with the following unit cell parameters and densities: DyLi₃Mg₃Mn₄O₁₂—a = 10.88 ?, b = 10.73 ?, c = 19.63 ?, V ⁰ = 1656.2 ?³, Z = 8, ρ_calc = 5.36 g/cm³, ρ_pycn = 5.11 ± 0.05 g/cm³; DyNaMg₃Mn₄O₁₂—a = 10.55 ?, b = 10.72 ?, c = 18.28 ?, V ⁰ = 2067.4 ?³, Z = 8, ρ_calc = 4.60 g/cm³, ρ_pycn = 4.88 ± 0.09 g/cm³; DyK₃Mg₃Mn₄O₁₂—a = 10.56 ?, b = 10.72 ?, c = 20.89 ?, V ⁰ = 2206.0 ?³, Z = 8, ρ_calc = 4.60 g/cm³, ρ_pycn = 4.92 ± 0.06 g/cm³; DyLi₃Ba₃Mn₄O₁₂—a = 10.53 ?, b = 10.69 ?, c = 21.28 ?, V ⁰ = 2395.4 ?³, Z = 8, ρ_calc = 5.58 g/cm³, ρ_pycn = 5.98 ± 0.12 g/cm³; DyNa₃Ba₃Mn₄O₁₂—a = 10.53 ?, b = 10.74 ?, c = 23.00 ?, V ⁰ = 2602.3 ?³, Z = 8, ρ_calc = 5.39 g/cm³, ρ_pycn = 5.30 ± 0.07 g/cm³; DyK₃Ba₃Mn₄O₁₂—a = 10.52 ?, b = 10.75 ?, c = 25.69 ?, V ⁰ = 2905.2 ?³, Z = 8, ρ_calc = 5.04 g/cm³, ρ_pycn = 5.00 ± 0.18 g/cm³.     

Heat capacity and thermodynamic functions of manganite ferrites NdMIMnFeO5 (MI = Li, Na) in the range of 298–673 K

The heat capacities of the new manganite ferrites NdM^IMnFeO₅ (M^I = Li, Na) are investigated in the range of 298.15–673 K by dynamic calorimetry. It is found that in the investigated temperature range, C _p ^○ ～ f(T) curves exhibit λ-shaped effects at 348 and 473 K for NdLiMnFeO₅, and at 423 K for NdNaMnFeO₅, corresponding probably to phase transitions of the second kind. Equations describing the experimentally obtained C _p ^○ ～ f(T) curves are derived, and the temperature dependences of the investigated compounds’ thermodynamic functions, S○(T), H○(T) ? H○(298.15), and Φ ^xx (T), are calculated.