Synthesis and study of the properties of K2Y1 ? x ? yEuxTby(MoO4)(PO4) and K2Y1 ? x ? yEuxTby(MoO4)(PO4)1?δ(VO4)δ solid solutions

Al synthesized samples are isostructural and crystallize in the orthorhombic symmetry system, space group Ibca. Particles of the final product of ∼200 nm in size have been obtained. The introduction of the vanadate anion into the matrix composition leads to the lowering of the symmetry of the Eu³⁺ environment and to the rise of the defect luminescence at 450–550 nm because of the unit cell distortion. The luminescence of defects in terbium-europium-containing samples is determined by the sample surface area, which decreases on annealing. The τ, W ₀ and γ parameters of the luminescence kinetics of the samples have been determined.     

Crystal structures of La1 ? xSr2 + x(GeO4)(V1 ? xMoxO4) (x= 0?0.4) solid solutions

The phase compositions of theLaVO₄-SrMoO₄(1) and Sr₂GeO₄-SrMoO₄ (2) binary systems, which bound the Sr₂GeO₄-LaVO₄-SrMoO₄ (3) ternary system, and the LaSr₂(VO₄)(GeO₄)-Sr₂GeO₄+SrMoO₄ section (4) of system 3 are studied at subsolidus temperatures. Systems 1 and 2 consist of a mixture of the initial compounds, and the La_{1 − x} Sr_{2 + x} (GeO₄)(V_{1 − x} Mo _x O₄) (where 0 ≤ x ≤ 0.4) region of substitutional solid solutions with a palmierite structure is formed in system 3. The unit cell parameters of the solid solutions are determined. The distribution of the lanthanum and strontium cations over two positions of the cationic sublattice is described. Original Russian Text ? V.D. Zhuravlev, V.G. Zubkov, A.P. Tyutyunnik, Yu.A. Velikodnyi, N.D. Koryakin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 135–137.     

Rubidium-conducting solid electrolytes in Rb2 ? 2xFe2 ? xVxO4 system

New solid rubidium-conducting electrolytes based on rubidium monoferrite in the system of Rb_{2 − 2x} Fe_2−x V _x O₄ are synthesized and studied. It is found that introduction of V⁵⁺ ions causes a drastic decrease in the electronic conductivity component prevalent in pure RbFeO₂ with a simultaneous increase in the ionic conductivity. The latter becomes predominant at an increase in the concentration of vanadium. The optimum compositions of the studied electrolytes feature a very high cationic rubidium conductivity (∼1.8 × 10⁻² S cm⁻¹ at 200°C, more than 10⁻¹ S cm⁻¹ at 700°C). The results are compared with the data obtained earlier for similar systems based on RbGaO₂ and RbAlO₂.     

A study of the structure of (HfO2)x(Al2O3)1?x/Si films by X-ray photoelectron spectroscopy

By X-ray photoelectron spectroscopy (XPS), using the technique of layer-by-layer analysis, the films of (HfO₂) _x (Al₂O₃)_1−x solid solutions synthesized by chemical vapor deposition are studied. The possibility to determine the structure of solid binary solutions based on the analysis of the XPS spectra is demonstrated.     

X-ray study of the thermolysis products of (NH4)2[OsCl6]x[PtCl6]1?x

Thermolysis of the complex salts (NH₄)₂[OsCl₆] _x [PtCl₆]_1−x (x = 0.25−0.9) formed nanocrystalline Os _x Pt_1−x phases. Pseudomorphism has been found: the habit of the single crystals of the starting salts is preserved during thermolysis, and the ∼10–20 nm metal particles are agglomerated into octahedral structures sized 5–10 μm.     

Conductivity of potassium-cationic solid electrolytes in the K0.85Pb0.075(Fe1 ? xAlx)O2 system

New potassium-conducting solid electrolytes in the mixed ferrite-aluminate system K_0.85Pb_0.075(Fe_{1 − x} Al _x )O₂ are synthesized and studied. The electrolytes exhibit high ionic conductivity in the studied temperature range of 350 to 750°C (approximately 10⁻² S/cm at 400°C and approximately 10⁻¹ S/cm at 700°C). An increase in the conductivity with increasing concentration of iron in the specimens is a general tendency. However, in a wide range of compositions (from x = 0.2 to x = 0.9), the conductivity only slightly depends on x. Possible reasons for the effect of Fe/Al ratio in the structure of solid electrolytes on their transport properties are discussed.     

Synthesis and X-ray diffraction study of complex oxides of the Zn2 ? x(ZraSnb)1 ? xFe2xO4 composition

A multicomponent system of complex refractory oxides of the composition Zn_{2 − x} (Zr _a Sn _b )_{1 − x} Fe_2x O₄ (a + b = 1; a: b = 1: 5, 1: 4, 1: 3, 1: 2, 1: 1, 2: 1, 3: 1, 4: 1; x = 0−1.0; Δx = 0.05) was studied by X-ray diffraction. The samples were prepared from oxides of appropriate metals by low-temperature plasma synthesis (hydrogen-oxygen flame). Two phases with wide homogeneity ranges were identified: α phase crystallized in the crystal system of inverse cubic spinel and β phase with the structure of tetragonal spinel. The phase boundaries were found. Structural data are presented for about 100 solid solutions.     

Structural and electric properties of the Ce0.8(Sm1 ? xCax)0.2O2 ? δ system (x = 0.0–1.0)

CeO₂-based solid solutions with a fluorite structure are promising materials as electrolytes of medium-temperature electrochemical devices. This work presents the results of systematic studies of structural and electric properties and oxygen nonstoichiometry of the Ce_0.8(Sm_{1 − x} Ca _x )_0.2O_{2 − δ} system in a wide range of concentrations of 0 < x < 1 performed in order to establish the causes affecting the system conductivity and its behavior in a reducing medium. It is found that a single-phase solid solution of the fluorite type is formed in the whole concentration range. Parameters of its lattice cells decrease linearly at an increase in the concentration of Ca²⁺. Conductivity in air grows when calcium is added due to a decrease in the grain boundary resistance. The maximum conductivity in air was obtained for the composition of Ce_0.8(Sm_0.8Ca_0.2)_0.2O_{2 − δ} and is 13.71 × 10⁻³ S/cm at 873 K. Studies of the dependence of conductivity of the partial pressure of oxygen showed that electron conductivity is observed at a higher oxygen partial pressure at an increase in the temperature and calcium concentration. The critical partial pressure of oxygen ( p_O2 ^* )\left( {p_{O_2 }^* } \right) for the compositions of Ce_0.8(Sm_{1 − x} Ca _x )_0.2O_{2 − δ} with x = 0; 0.2, and 0.5 is 1.83 × 10⁻¹⁶, 1.73 × 10⁻¹³, and 3.63 × 10⁻¹³ atm at 1173 K, respectively, and 2.76 × 10⁻²¹, 5.05 × 10⁻¹⁸, and 1.31 × 10⁻¹⁸ atm at 1023 K.     

Ca2-3xLa8+2x□x(SiO4)6O2的合成及其导电性能的研究

The silicate oxyapatites Ca_2-3xLa_8+2x□_x(SiO₄)₆O₂(x=0, 0.17, 0.33, 0.50, 0.67) was synthesized via a sol-gel method at low temperature. The apatite phases have been characterised by X-ray diffraction (XRD), conducting properties was studied by electrical chemistry impedance spectroscopy (EIS). The conductivity of La_9.33□_0.67(SiO₄)₆O₂ is 1.58×10^-3 S·cm^-1 at 700 ℃, it is higher about 4 270 times than that of Ca₂La₈(SiO₄)₆O₂, the activation energy is decreasing from 1.37 eV to 0.84 eV. With cation vacancies increasing,the conducting mechanism is gradually translation from a direct linear pathway free oxygen ion conduction to a curve pathway interstitial oxygen ion conduction. The electrical conductivities is almost independent of the oxygen partial pressure, this suggests that the oxyapatites exhibited almost pure O^2- ion conduction over a wide range of oxygen partial pressure.     

Synthesis and thermolysis of substitutional solid solutions (Cu1?yMy)2(OH)PO4·xH2O (x = 0.1?0.2; M = Zn, Co, Ni)

Substitutional solid solutions (Cu_1−y Zn _y )₂(OH)PO₄·xH₂O (0 ≤ y ⩽ 0.26, x = 0.1−0.2), (Cu_1−y Co _y )₂(OH)PO₄·xH₂O (0 ≤ y ≤ 0.10, x = 0.1−0.2), and (Cu_1−y Ni _y )₂(OH)PO₄·xH₂O (0 ≤ y ≤ 0.08, x = 0.1−0.2) were synthesized. The unit cell parameters of the resulting phosphates were determined, and their IR absorption spectra were measured. The reactants were H3PO4 and mixtures of hydrous carbonates of the appropriate metals. Thermolysis of the solid solutions was examined with (Cu_1−y Co _y )₂(OH)PO₄·xH₂O (0 ≤ y ≤ 0.10, x = 0.1−0.2) as an example.     

Solid solutions of Ba2(In1 ? xAlx)2O5: Structural evolution and hydration processes

Solid solutions of the composition Ba₂(In_{1 − x} Al _x )₂O₅[VO]₁ (0 ≤ x ≤ 0.20) with an incomplete oxygen sublattice were obtained. It was established that, along with an increase in parameter x, there is disordering of oxygen vacant positions and a transition from the structure of brownmillerite to that of defect perovskite. It was demonstrated that the phases under study are characterized by an ability for reversible interaction with water vapors in the temperature range 150–450°C. During this process, proton defects, predominantly in the form of OH⁻ groups, are formed in the oxide structure. We conclude that in a number of solid solutions, the amount of intercalated water declines upon an increase in the aluminum content.     

EPR study of solid solutions of [Cr(NH3)5Cl]x[Rh(NH3)5Cl]1?x[PdCl4]·nH2O and [Cr(NH3)5Cl]x[Rh(NH3)5Cl]1?x[PtCl4] compounds

In order to determine the features of the structure of double complex salts (DCSs) of [Cr(NH₃)₅Cl]×[MCl₄]·nH₂O, where M = Pd, Pt, n = 0, 1, the DCS solid solutions of palladium and platinum with isostructural DCSs containing the chloropentaammine rhodium cation, [Cr(NH₃)₅Cl] _x [Rh(NH₃)₅Cl]_1−x [MCl₄]·nH₂O, where x = 0.01–0.2, are synthesized and studied by the EPR method. DCSs with the isostructural chloropentaammine rhodium cation are used as a diluter for magneto concentrated systems. It is shown that DCS of platinum and anhydrous DCS of palladium have the identical environment of chromium ions. The EPR spectra of chromium ions for these compounds are described by the following spin Hamiltonian parameters: S = 3/2, g _xx = 1.987, g _yy = 1.987, g _zz = 1.985, D = 1660 Gs, E = 235 Gs. For the palladium complex containing crystalline water, the EPR spectra of chromium ions are described by the parameters: S = 3/2, g _xx = 1.984, g _yy = 1.984, g _zz = 1.984, D = 1060 Gs, E = 350 Gs. A decrease in the crystal field parameters for the aqueous palladium complex is caused by a redistribution of the electron density to the oxygen atom in the second sphere of the chromium ion environment.     

The enthalpies of formation of Sm1 + xBa2 ? xCu3Oy substitution solid solutions

The enthalpies of reactions of Sm_{1 + x} Ba_{2 − x} Cu₃O _y substitution solid solutions (x = 0, 0.1, 0.2, 0.3, 0.7, and 0.8) with 1.07 N HCl were measured at 298.15 K in a hermetic isothermic-shell swinging calorimeter. The results and the literature data were used to calculate the standard enthalpies of their formation from simple substances and binary oxides (Δ_f H _298.15^o and Δ_ox H _298.15^o). The dependence of the enthalpy of formation on the degree of samarium substitution for barium was obtained.     

Phase transitions and ion transport in NASICON materials of composition Li1 + xZr2 ? xInx(PO4)3(x = 0–1)

NASICON materials of composition Li_{1 + x} Zr_{2 − x} In _x (PO₄)₃(x = 0–1) were synthesized. The phase constitution, particle size, and conductivity of these materials were studied as s function of synthesis temperature. High-temperature X-ray powder diffraction was used to study phase transitions in the materials synthesized. Low levels (x ≤ 0.1) partial substitution of indium for zirconium considerably increase the lithium ion conductivity and reduce the activation energy for conduction compared to the parent compound.     

Total and hole conductivity in the BaZr1 ? xYxO3 ? α system (x = 0.02?0.20) in oxidizing atmosphere

The total and hole (p-type) conductivities are measured in the BaZr_{1 − x} Y _x O_{3 − α} system (x = 0.02−0.20) in the temperature range of 600–900°C as a function of air humidity (pH₂O = 0.04−3.17 kPa). The model of defect formation in BaZr_{1 − x} Y _x O_{3 − α} oxides in the presence of water vapor is discussed and the literature data are analyzed.     

Synthesis and study of the variable-composition phase Na1?xCo1?xFe1+x(MoO4)3, 0 ≤ x ≤ 0.4, with nasicon structure

The synthesis conditions for variable-composition phase Na_1−x Co_1−x Fe_1+x (MoO₄)₃, 0 ≤ x ≤ 0.4, crystallizing in the nasicon structure type (R $ \bar 3 $ \bar 3 c) were examined. For this phase, the crystallographic parameters were calculated, vibrational spectra were interpreted, and temperature dependence of electrical conductivity, dielectric constant, and dielectric loss tangent were examined.     

Dehydrogenation of butyl alcohols on NASICON-type solid electrolytes of Na1 ? 2xCuxZr2(PO4)3 composition

Characteristics of the catalytic activity in the dehydration of butanols of copper-containing sodium-zirconium-phosphates (NZPs), in which Na⁺ ions substitute for Cu²⁺ ions are obtained. It was found that in the 100–370°C region, the action energy of the reaction falls upon the transition through temperature T* ∼ 300°C, above which the electrophysical and crystallographic properties of phosphates change. The observed dependences are explained by the center (which consists of copper with various positions in the phosphate network at T < T* and T > T*) taking part in the formation of carbonyl compounds. This indicates the presence of a ligand effect, i.e., to structural sensitivity of the dehydration reaction in the case of Cu-NZP catalysts.     

Cation mobility in modified Li1 + xTi2 ? xGax(PO4)3 lithium titanium NASICON phosphates

Li_{1 +x} Ti_{2 − x} Ga _x (PO₄)₃(x= 0−0.2) NASICON double phosphates are prepared and studied by high-temperature X-ray diffraction, ⁷Li NMR spectroscopy, impedance spectroscopy, and calorimetry. Doping with Ga³⁺ cations increases cation mobility in LiTi₂(PO₄)₃. Ion conductivity, NMR spectroscopy, and calorimetry data imply the occurrence of a phase transition in LiTi₂(PO₄)₃ and in products of partial gallium-for-titanium substitution. Original Russian Text ? I.Yu. Pinus, I.V. Arkhangel’skii, N.A. Zhuravlev, A.B. Yaroslavtsev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 8, pp. 1235–1239.     

Cation mobility in modified Li1 ? xTi2 ? xNbx(PO4)3 lithium titanium NASICON phosphates

Li_{1 − x} Ti_{2 − x} Nb _x (PO₄)₃ NASICON materials are prepared and studied by X-ray diffraction, ⁷Li and ³¹P NMR spectroscopy, and impedance spectroscopy. Vacancy mobility in Li_{1 − x} Ti_{2 − x} Nb _x (PO₄)₃ is lower than interstitial lithium mobility. Nb⁵⁺ cations with low doping levels increase cation mobility in LiTi₂(PO₄)₃. Original Russian Text ? I.Yu. Pinus, I.A. Stenina, A.I. Rebrov, N.A. Zhuravlev, A.B. Yaroslavtsev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 8, pp. 1240–1244.     

The enthalpies of formation of substitution solid solutions Pr1 + xBa2 ?xCu3Oy

The enthalpies of reactions of substitution solid solutions Pr_{1 + x} Ba_{2 − x}Cu₃O _y , where x = 0, 0.2, 0.4, 0.6, and 0.9, with 1.07 N HCl were measured at 298.15 K in a hermetic swinging isothermic-shell calorimeter. The results and the literature data were used to calculate the standard enthalpies of formation of solid solutions from the elements and oxides. The dependence of the enthalpy of solid solution formation on the degree of praseodymium substitution for barium (x) was revealed.