Phases of variable composition in the system Ba3 ? x Sr x Er(BO3)3 (0 ≤ x ≤ 3.0)

The possibility of preparing two series of solid solutions in the system Ba_{3 − x} Sr _x Er(BO₃)₃ (0 ≤ x ≤ 3.0), crystallizing in different structural types, was examined. Samples of the phases of variable composition were synthesized by the method of solid-phase reactions, and their X-ray phase analysis was done. The X-ray diffraction characteristics of the phases synthesized were determined. Original Russian Text ? T.N. Khamaganova, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 7, pp. 1210–1212.     

Mechanism studies and electrochemical performance optimization on xLiFePO4·(1 ? x)Li3V2(PO4)3 hybrid materials

Hybrid materials xLiFePO₄·(1 − x)Li₃V₂(PO₄)₃ were synthesized by sol–gel method, with phenolic resin as carbon source and chelating agent, methylglycol as surfactant. The crystal structure, morphology and electrochemical performance of the prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge–discharge test and particle size analysis. The results show that LiFePO₄ and Li₃V₂(PO₄)₃ co-exist in hybrid materials, but react in single phase. Compared with individual LiFePO₄ and Li₃V₂(PO₄)₃ samples, hybrid materials have smaller particle size and more uniform grain distribution. This structure can facilitate Li ions extraction and insertion, which greatly improves the electrochemical properties. The sample 0.7LiFePO₄·0.3Li₃V₂(PO₄)₃ retains the advantages of LiFePO₄ and Li₃V₂(PO₄)₃, obtaining an initial discharge capacity of 166 mA h/g at 0.1 C rate and 109 mA h/g at 20 C rate, with a capacity retention rate of 73.3% and an excellent cycle stability.     

Transport numbers and ionic conduction of eutectic methacomposites {(1 ? x )MeWO4 · x WO3}) (Me = Sr, Ba; x = 0?0.55)

Transport numbers of oxygen ions, , in methacomposites (1 − x)MeWO₄ · xWO₃, where Me = Sr and Ba and x = 0−0.55, are determined in the temperature interval 600 to 900°C by a method of the emf of an oxygen-air galvanic cell. It is demonstrated that the region of small contents of the additive (x ≤ 0.2) is predominantly characterized by oxygen-ion conduction ( = 1), which gives way to electronic conduction (t _e = 1) at x > 0.35. It is confirmed once again that subeutectic compositions (1 − x)MeWO₄ · xWO₃ where Me = Sr and Ba and x = 0−0.2 belong in the class of ion-conducting methacomposites. The threshold of percolation of electronic conduction (t _e ≥ 0.5, < 0.5) occurs at x _t ≥ 0.3. Dependences of the transport numbers of the oxygen ions on the volume ratio between components in both composites resemble one another; specifically, the threshold composition contains nearly 20 vol % of WO₃. The dramatic amplification (by 1–1.5 orders of magnitude) of the ionic conductivity in the methacomposites occurs at small contents of tungstic oxide (x ≤ 0.01). A chemical transport removal of excess tungstic oxide, which is segregated in the form of the surface compound MeW-s, from the surface of the MeWO₄ grains destroys MeW-s, leading to a 10–15-fold drop of the ionic conductance. At x ≥ 0.05, the oxygen-ion conductance in the methacomposites is practically independent of their composition. A model for the formation and architecture of the methacomposites is qualitatively modified. The modified model takes into account doubled surface activity and mobility of the MeW-s phase with respect to MeWO₄ and WO₃. Original Russian Text ? N.N. Pestereva, A.Yu. Zhukova, A. Ya. Neiman, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 11, pp. 1379–1386.     

xLi2MnO3·(1-x)LiNi1/3Co1/3Mn1/3O2(x=0.1、0.2、0.3和0.4)固溶体材料性能研究

通过LiNO3与Mn(NO3)2的混合溶液与LiNi1/3Co1/3Mn1/3O2粉体共混干燥后在900℃热处理12 h制备了xLi2MnO3.(1-x)LiNi1/3Co1/3Mn1/3O2(x=0.1、0.2、0.3和0.4)固溶体。随着x的增加,固溶体的XRD峰强度减弱,峰形变宽,而在20°~30°间的结构特征峰(LiMn6)更加明显;尽管固溶体的外观形貌为团聚状,但组成其的单颗粒平均粒径随着x增大,由x=0.1时的250 nm增大到x=0.4时的350 nm。随着充放电截止电压的升高,固溶体的放电比容量增大;在2.5~4.6 V间充放电,当x=0.2时,充放电的极化最小,放电平台最高;不同倍率充放电循环21周后发现随着x的增大,容量保持率从91.2%增加大105.6%。研究结果表明,Li2MnO3可以改善LiNi1/3Co1/3Mn1/3O2材料的电化学性能。     

Structure of complex salts [Co(NH3)6][Rh(NO2)6] and [Co(NH3)6][(NO2)3Rh(μ-NO2)1+x(μ-OH)2?xRh(NO2)3]·(2-x)(H2O), x = 0.17

The structures of two salts [Co(NH₃)₆][Rh(NO₂)₆] (I) and [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 (II) are solved. Single crystals of the salts are obtained by the counter diffusion method through the gel of aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][Rh(NO₂)₆] is consistent with the diffraction data for a polycrystalline sample of poorly soluble fine salt formed in the exchange reaction between aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 exhibits the stabilizing effect of a large cation in the formation of novel, unknown previously coordination ions: [(NO₂)₃Rh(μ-NO₂)(μ-OH)₂Rh(NO₂)₃]³⁻ and [(NO₂)₃Rh(μ-NO₂)₂(μ-OH)Rh(NO₂)₃]³⁻.     

Kinetic effects in n -CdAs2, p -ZnAs2, and Cd x Zn1 ? x As2 solid solutions

The electrical resistivity and Hall factor in n-CdAs₂, p-ZnAs₂, and n-Cd _x Zn_{1 − x} As₂ were measured at hydrostatic pressures up to 9 GPa and quasi-hydrostatic pressures up to 50 GPa at room temperature. For n-CdAs₂, a phase transition was discovered at p = 5.5 GPa; for p-ZnAs₂, two phase transitions were discovered: one at P = 10–15 GPa and the other at p = 35–40 GPa. No anomalies were found on ρ(p) and R(p) curves for Cd _x Zn_{1 − x} As₂ when p ≤ 9 GPa. Original Russian Text ? A.Yu. Mollaev, I.K. Kamilov, R.K. Arslanov, L.A. Saipulaeva, R.G. Dzhamamedov, S.F. Marenkin, A.N. Babushkin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 122–125.     

Preparation of (1? x %)(Na0.5Bi0.5)TiO3– x %SrTiO3 thin films by a sol–gel method for dielectric tunable applications

(1−x%)(Na_0.5Bi_0.5)TiO₃–x%SrTiO₃ (NBTSx) thin films were deposited on Pt/TiO₂/SiO₂/Si substrates by a spin-on sol–gel method and rapid thermal annealing. The stock solutions were prepared using sodium acetate, bismuth acetate, strontium acetate, and titanium n-butoxide as precursors, ethanol, and acetic acid as solvents and acetylacetone as the chelating agent. The thermal treatment conditions were determined by thermal analyses of the dry gel powders derived from the stock solutions. Structure and dielectric tunable properties of the films were studied as functions of Sr concentration. NBTSx films exhibit the perovskite structure of a pseudo-cubic symmetry with the lattice parameters increasing with increasing Sr concentration. It was found that the substitution of Sr in Na_0.5Bi_0.5TiO₃ may greatly reduce the dielectric loss while decrease the tunability at the same time. The best figure of merit was achieved in NBTS80 films. The results were discussed and compared with related materials.     

Existence region, structure, and properties of YBa(Cu1? x Fe x )2O5+δ and (Y1? y Ba y )2 CuFeO5+δ solid solutions

We study the effect of Y³⁺ ↔ Ba²⁺ and Cu²⁺ ↔ Fe³⁺ substitutions on the structure, thermal expansion, electrical conductivity, and thermal e.m.f. of layered ferrocuprate YBaCuFeO_{5 + δ} · YBa(Cu_1−x Fe _x )₂O_{5 + δ} solid solutions with 0.45≤x≤0.55 are formed. The unit cell parameters, thermal expansivity, and oxygen nonstoichiometry index of the YBaCuFeO_{5 +δ} phase (δ) are almost independent of variations in the cationic composition of this phase. The electrical conductivity of layered yttrium barium ferrocuprate increases, whereas the activation energy of conductivity decreases in response to Ba²⁺ → Y³⁺ and Cu²⁺ → Fe³⁺ substitutions (with increasing copper(III) proportion in samples). The thermal e.m.f. of ceramics decreases when composition deviates from the cationic stoichiometry (YBaCuFeO_{5 +δ}). Original Russian Text ? A.I. Klyndyuk, E.A. Chizhova, V.M. Kononovich, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1672–1676.     

Synthesis and thermal characterization of NZP compounds Na1?xLixZr2(PO4)3 (x?=?0.00–0.75)

Sodium zirconium phosphate (NZP) composition Na_1−x Li _x Zr₂(PO₄)₃, x = 0.00–0.75 has been synthesized by method of solid state reaction method from Na₂CO₃·H₂O, Li₂CO₃, ZrO₂, and NH₄H₂PO₄, sintering at 1050–1250 °C for 8 h only in other to determine the effect on thermal properties, such as the phase formation of the compound. The materials have been characterized by TGA and DTA thermal analysis methods from room temperature to 1000 °C. It was observed that the increase in lithium content of the samples increased thermal stability of the samples and the DTA peaks shifted towards higher temperatures with increase in lithium content. The thermal stability regions for all the sample was observed to be from 640 °C. The sample with the highest lithium content, x = 0.75, exhibited the greatest thermal stability over the temperature range.     

xLi2MnO3-(1-x) Li[Ni0.8Co0.15Al0.05]O2(0.5 ≤ x ≤ 0.8)的结构和电化学性能

采用喷雾干燥法结合后续的热处理,成功地制备了一系列新型的基于富锂层状固溶体Li_2MnO_3和Li[Ni_(0.8)Co_(0.15)Al_(0.05)]O_2结合的xLi_2MnO_3-(1-x)Li[Ni_(0.8)Co_(0.15)Al_(0.05)]O_2(0.5≤x≤0.8)材料,并对其晶体结构、表面形貌、元素价态以及电化学性能进行了一系列的研究。实验结果表明,随着x值的增大,材料的晶体结构逐渐从层状的Li[Ni_(0.8)Co_(0.15)Al_(0.05)]O_2过渡到类Li_2MnO_3结构。对样品进行淬火处理对晶粒的微观晶体结构和元素价态产生复杂影响,这种变化使得淬火的样品表现出较好的电化学性能。其中x=0.6的样品淬火后表现出较好的电化学性能,100次循环后可逆容量可达209 mAh·g~(-1)。     

NASICON phases of variable composition K1? x A1? x R1+ x (MoO4)3 (0 ≤ x ≤ 0.2–0.6), where A = Ni, Mg, Co, or Mn and R = Yb, Lu, or Sc

Phases of variable composition K_1−x A_1−x R_1+x (MoO₄)₃) (0 ≤ x ≤ 0.2–0.6), where A = Ni, Mg, Co, or Mn and R = Yb, Lu, or Sc, which crystallize in a NASICON-type structure (space group R c) were synthesized by solid-phase reactions. Their crystal parameters were calculated, and IR and Raman spectra described. Original Russian Text ? N.M. Kozhevnikova, T.N. Khamaganova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 5, pp. 864–865.     

Li-cycling properties of nano-crystalline (Ni1 ? xZnx)Fe2O4 (0 ≤ x ≤ 1)

Sol–gel auto-combustion method is adopted to prepare solid solutions of nano-crystalline spinel oxides, (Ni_1 − x Zn _x )Fe₂O₄ (0 ≤ x ≤ 1).The phases are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy, selected area electron diffraction, and Brunauer–Emmett–Teller surface area. The cubic lattice parameters, calculated by Rietveld refinement of XRD data by taking in to account the cationic distribution and affinity of Zn ions to tetrahedral sites, show almost Vegard’s law behavior. Galvanostatic cycling of the heat-treated electrodes of various compositions are carried in the voltage range 0.005–3 V vs. Li at 50 mAg⁻¹ up to 50 cycles. Phases with high Zn content x ≥ 0.6 showed initial two-phase Li-intercalation in to the structure. Second-cycle discharge capacities above 1,000 mAh g⁻¹ are observed for all x. However, drastic capacity fading occurs in all cases up to 10–15 cycles. The capacity fading between 10 and 50 cycles is found to be greater than 52% for x ≤ 0.4 and for x = 0.8. For x = 0.6 and x = 1, the respective values are 40% and 18% and a capacity of 570 and 835 mAh g⁻¹ is retained after 50 cycles. Cyclic voltammetry and ex situ transmission electron microscopy data elucidate the Li-cycling mechanism involving conversion reaction and Li–Zn alloying–dealloying reactions.     

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.     

Ag1 ? xMg1 ? x R1 + x(MoO4)3 Ag+-conducting NASICON-like phases, where R = Al or Sc and 0 ≤ x ≤ 0.5

Ag_{1 − x} Mg_{1 − x} R_{1 + x} (MoO₄)₃ NASICON-like solid solutions, where R = Al or Sc and 0 ≤ x ≤ 0.5, were prepared; their crystal lattice parameters and thermal stabilities were determined. Silver-ion conductivity was measured, and conductivity activation energy values were calculated for various temperature ranges. Above 400°C, Ag_{1 − x} Mg_{1 − x} R_{1 + x} (MoO₄)₃ phases have ionic conductivities comparable to the conductivities of sodium-ion and lithium-ion NASICON-like conductors. The conductivity increases as the tervalent cation radius increases or the amount of mobile silver ions increases.     

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.     

Ga掺杂La9+x/3(GeO4)6-x(GaO4)xO1.5的合成及导电性能研究

利用固相法合成系列Ga掺杂缺陷氧锗氧基磷灰石La9+x/3(GeO4)6-x(GaO4)xO1.5(sx=0,0.5,1,1.5).X射线粉末衍射结果表明:反应物在1350℃烧结24 h即可得到磷灰石结构的纯相产物.700℃时La9.5((GeO4)4.5(GaO4)1.5O1.5的电导率达到3.162×10-3 S·cm-1,是同温度La9(GeO4)6O1.5(1.259×10-3 S·cm-1)电导率的2.5倍.氧分压测试结果表明:材料的电导率在Po2=1～105 Pa保持不变,证明材料在较宽的氧分压范围内为O2-导电.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F [`4]\bar 4 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed.     

(p, ρ, T, x) properties for CO2/isobutane binary mixtures at T = (280 to 440) K and (3 to 200) MPa

The (p, ρ, T, x) properties for binary mixtures of CO₂ (volume fraction purity 0.99999) and isobutane (mole fraction purity 0.99988) {x₁ CO₂ + x₂ isobutane (x₁ = 0.2482, 0.4718, and 0.7506)} were measured in the compressed liquid phase using a metal-bellows variable volumometer. Measurements were conducted from T = (280 to 440) K and (3 to 200) MPa. The expanded uncertainties (k = 2) were estimated to be: temperature, <3 mK; pressure, 1.5 kPa (p ? 7 MPa), 0.06% (7 MPa < p ? 50 MPa), 0.1% (50 MPa < p ? 150 MPa), 0.2% (p > 150 MPa); density, 0.10%; and composition, 4.4 · 10⁻⁴. At >100 MPa and T = (280 or 440) K, the uncertainties in the density measurements increased to 0.14% and 0.22%, respectively. The data are compared with the available equation of state. The excess molar volumes, , of the mixtures were calculated and plotted as a function of temperature and pressure.     

Rare earth metal-rich indides RE 4IrIn ( RE = Gd–Er), RE 4IrInO0.25 ( RE = Gd, Er), and RE 4 T In1– x Mg x ( RE = Y, Gd; T = Rh, Ir)

The rare earth-transition metal-indides RE ₄IrIn (RE = Gd–Er) and the solid solutions RE ₄ TIn_1–x Mg _x (RE = Y, Gd; T = Rh, Ir) were prepared by arc-melting of the elements and subsequent annealing. The rare earth sesquioxides were used as oxygen source for the suboxides RE ₄IrInO_0.25 (RE = Gd, Er). Single crystals of the indides were grown via slowly cooling of the samples and they were investigated via X-ray powder diffraction and single crystal diffractometer data: Gd₄RhIn type, F 3m, a = 1372.3(6) pm for Gd₄IrIn, a = 1365.3(6) pm for Tb₄IrIn, a = 1356.7(4) pm for Dy₄IrIn, a = 1353.9(4) pm for Ho₄IrIn, a = 1344.1(4) pm for Er₄IrIn, a = 1370.3(5) pm for Y₄RhIn_0.54Mg_0.46, a = 1375.6(5) pm for Gd₄IrIn_0.55Mg_0.45, a = 1373.0(3) pm for Gd₄IrInO_0.25, and a = 1345.1(4) pm for Er₄IrInO_0.25. The rhodium and iridium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ and IrRE ₆ prisms leads to three-dimensional networks which leave voids that are filled by regular In₄ or mixed In_4–x Mg _x tetrahedra. The indium (magnesium) atoms have twelve nearest neighbors (3In(Mg) + 9RE) in icosahedral coordination. The rare earth atoms build up a three-dimensional, adamantane-like network of condensed, edge and face-sharing octahedra. For Gd₄IrInO_0.25 and Er₄IrInO_0.25 the RE1₆ octahedra are filled with oxygen. The crystal chemical peculiarities of these rare earth rich compounds are discussed. Correspondence: Rainer P?ttgen, Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms-Universit?t Münster, Germany.     

Structure and thermal properties of [Ir(NH3)5Cl]x[Rh(NH3)5Cl]1?xMO4 (x = 0.5, 1; M = Mo, W)

Complex salts [Ir(NH₃)₅Cl]x[Rh(NH₃)₅Cl]_1−x MO₄ (x = 0.5, 1; M = Mo, W) are synthesized and their thermal properties are studied. The crystal structures are determined for [Ir(NH₃)₅Cl]WO₄ and [Ir(NH₃)₅Cl]MoO₄. In the structures, the ions are linked by N-H...O hydrogen bonds, the shortest ones being 2.868(2)–3.422(2) ?. and 2.860(4)–3.434(3) ?. respectively. The thermal properties of the complex salts are studied in the hydrogen atmosphere and in hydrogen-helium mixtures. It is demonstrated that the final products are the mixtures of nanocrystalline powders of Ir and binary or ternary solid solutions with the hcp lattice.