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.     

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.     

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⁻.     

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.     

Phase formation in the Ba3? x Sr x Y(BO3)3 system (0 < x < 3)

Phases of a variable composition in the Ba_3−x Sr _x Y(BO₃)₃, system (0 < x < 3) have been investigated for the first time using the solid-phase reactions method. The formation of two series of solid solutions crystallizing in different structural types have been established using X-ray diffraction (D-8 Advance diffractometer, CuK _α radiation, graphite monochromator). Crystal characteristics of obtained phases have been determined. Original Russian Text ? T.N. Khamaganova, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 553–556.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Thermal expansion and heat capacity measurements on Ba10?xCsx(PO4)6Cl2?δ, (x?=?0, 0.5) chloroapatites synthesized by sonochemical process

Ba_10−x Cs _x (PO₄)₆Cl₂, (x = 0, 0.5) chloroapatite ceramics were prepared by sonochemical method of synthesis. The measured room temperature lattice parameters of Ba₁₀ (PO₄)₆Cl₂ and Ba_9.5Cs_0.5 (PO₄)₆Cl_2−δ are practically the same; that is, a = 10.26 (8), c = 7.65 (7) and a = 10.27 (7), c = 7.65 (5), respectively. Heat capacity measurements were carried out on these materials by differential scanning calorimetry (DSC) in the temperature range 298–800 K. The heat capacity values of Ba_9.5Cs_0.5(PO₄)₆Cl_2−δ are found to be slightly higher at all temperatures than those of Ba₁₀(PO₄)₆Cl₂. From the heat capacity data, other thermodynamic functions such as enthalpy and entropy increments were computed. The heat capacity values of Ba₁₀(PO₄)₆Cl₂ and Ba_9.5Cs_0.5(PO₄)₆Cl_2−δ at 298 K are 0.3912 and 0.4310 J K⁻¹ g⁻¹, respectively. Thermal expansion property of the doped and undoped barium chloroapatites was measured by using a home built dilatometer which uses LVDT as displacement sensor. The bulk thermal expansion of Ba₁₀(PO₄)Cl₂ and Ba_9.5Cs_0.5(PO₄)Cl_2−δ is observed to be about 0.9% in the temperature range of 298–973 K.     

Complexation of M–(buffer) x –(OH) y Systems Involving Divalent Ions (Cobalt or Nickel) and Zwitterionic Biological Buffers (AMPSO, DIPSO, TAPS and TAPSO) in Aqueous Solution

The complexation behavior of eight M–(buffer) _x –(OH) _y systems involving two divalent ions (cobalt and nickel) and four zwitterionic biological buffers (AMPSO, DIPSO, TAPS and TAPSO) were characterized. Complex formation was detected for all eight M–(buffer) _x –(OH) _y systems studied, but fully defined final models were obtained for only four of these systems. For systems involving cobalt or nickel with AMPSO or TAPS, a complete characterization of the systems was not possible in the studied buffer pH-range. Metal complexation was studied by glass-electrode potentiometry (GEP) and UV-Vis spectroscopy at 25.0 °C and I=0.1 mol⋅dm⁻³ KNO₃ ionic strength. For the Ni–(L) _x –(OH) _y and Co–(L) _x –(OH) _y systems, with L = TAPSO or DIPSO, the proposed final models and overall stability constants were obtained by combining results from both techniques. For the Ni–(L) _x –(OH) _y systems, the measured values of the stability constants are log ₁₀ β _NiL=3.0±0.1 and log ₁₀ β _NiL2=4.8±0.1 for L = TAPSO, and log ₁₀ β _NiL=2.7±0.1 and log ₁₀ β _NiL2=4.6±0.1 for L = DIPSO. For the Co–(L) _x –(OH) _y systems, the overall stability constants are log ₁₀ β _CoL=2.2±0.1, log ₁₀ β _CoL2=3.6±0.2 and log ₁₀ β _CoL(OH)=7.6±0.1 for L = TAPSO, and log ₁₀ β _CoL=2.0±0.1 and log ₁₀ β _CoL(OH)=7.8±0.1 for L = DIPSO. For both buffers, the CoL(OH) species is characterized by a major structural rearrangement.     

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.     

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.     

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.     

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.     

Unsaturation in binuclear cyclopentadienylchromium carbonyl thiocarbonyls: Viability of (η-C5H5)2Cr2(CS)2(CO)3 in contrast to (η-C5H5)2Cr2(CO)5

The cyclopentadienylchromium carbonyl thiocarbonyls Cp₂Cr₂(CS)₂(CO)_n (n = 4, 3, 2, 1) have been studied by density functional theory using the B3LYP and BP86 functionals. The lowest energy Cp₂Cr₂(CS)₂(CO)₄ structure can be derived from the experimentally characterized unbridged Cp₂Cr₂(CO)₆ structure by replacing the two terminal carbonyl groups furthest from the Cr-Cr bond with two terminal CS groups. The two lowest energy Cp₂Cr₂(CS)₂(CO)₃ structures have a single four-electron donor η²-μ-CS group and a formal Cr-Cr single bond of length ∼3.1 Å. In contrast to the carbonyl analogue Cp₂Cr₂(CO)₅ these Cp₂Cr₂(CS)₂(CO)₃ structures are viable with respect to disproportionation into Cp₂Cr₂(CS)₂(CO)₄ and Cp₂Cr₂(CS)₂(CO)₂ and thus are promising synthetic targets. The lowest energy Cp₂Cr₂(CS)₂(CO)₂ structures have all two-electron donor CO and CS groups and short CrCr distances around ∼2.3 Å suggesting the formal triple bonds required to give the chromium atoms the favored 18-electron configurations. These Cp₂Cr₂(CS)₂(CO)₂ structures are closely related to the known structure for Cp₂Cr₂(CO)₄. In addition, several doubly bridged structures with four-electron donor η²-μ-CS bridges are found for Cp₂Cr₂(CS)₂(CO)₂ at higher energies. The global minimum Cp₂Cr₂(CS)₂(CO) structure is a triply bridged triplet with a CrCr triple bond (2.299 Å by BP86). A higher energy singlet Cp₂Cr₂(CS)₂(CO) structure has a shorter Cr-Cr distance of 2.197 Å (BP86) suggesting the formal quadruple bond required to give each chromium atom the favored 18-electron configuration.     

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.