Crystal structure and vibrational spectra of M[VO<Subscript>2</Subscript>(SeO<Subscript>4</Subscript>)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]·H<Subscript>2</Subscript>O (M = K,Rb, NH<Subscript>4</Subscript>)

By the hydration of MVO(SeO₄)₂ with saturated water vapors at room temperature a series of isostructural complex compounds of vanadium(V) of the composition M[VO₂(SeO₄)(H₂O)₂]·H₂O (K, Rb, NH₄) are synthesized and their physicochemical properties are studied. Based on the X-ray and neutron diffraction data, it is found that their crystal structure is composed of VO₆ octahedra linked in infinite chains by bridging SeO₄ tetrahedra. Each of the VO₆ octahedra has two short terminal V-O bonds forming a bent dioxovanadium group VO₂⁺. Two water molecules are coordinated by vanadium and one molecule is out of the first coordination sphere in the interchain space. The vibrational spectra of the studied compounds are completely consistent with their structural features.     

Synthesis and physicochemical study of M<Subscript>4</Subscript>Na<Subscript>2</Subscript>V<Subscript>10</Subscript>O<Subscript>28</Subscript> · 10H<Subscript>2</Subscript>O (M=K,Rb, NH<Subscript>4</Subscript>)

The formation conditions and physicochemical properties of binary decavanadates M₄Na₂V₁₀O₂₈ · 10H₂O (M=K, Rb, NH₄), synthesized by crystallization from saturated solutions of the NaVO₃-MH₂AsO₄-H₂O systems, were studied by chemical analysis, X-ray powder diffraction, microscopy, thermogravimetry, and IR spectroscopy. To optimize the synthesis conditions of M₄Na₂V₁₀O₂₈ · 10H₂O, the ( 1-x)NaVO₃ · 2H₂O · xMH2AsO4-H₂O (0.2 ≤ x ≤ 0.8) isomolar series method was applied to studying the interaction in the NaVO₃-MH₂AsO₄-H₂O systems (M = K, Rb, Cs) at the 0.4 mol/L total molar concentration of NaVO₃ and MH₂AsO₄ in solutions. The studied M₄Na₂V₁₀O₂₈ · 10H₂O compounds were shown to be isostructural with triclinic crystals (Z= 1, space group P $ \bar 1 $ \bar 1 ), and their unit cell parameters were estimated.     

Structure and thermal properties of double complex salts [RuNO(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>(H<Subscript>2</Subscript>O)]<Subscript>2</Subscript>[MCl<Subscript>4</Subscript>]Cl<Subscript>4</Subscript>·2H<Subscript>2</Subscript>O,M = Pt,Pd

Double complex salts (DCS) [RuNO(NH₃)₄(H₂O)]₂[MCl₄]Cl₄·2H₂O, M = Pt (I) and Pd (II), are prepared and characterized using IR spectroscopy, single crystal and powder X-ray diffraction, and thermogravimetric analysis. Crystalline phases of I and II are isostructural (P2(1)/n space group) and have the following crystallographic characteristics: a = 6.689 Å, b = 15.609 Å, c = 12.348 Å, V = 1289.1 ų, Z = 2, d _x = 2.425 g/cm³ (I) and a = 6.637 Å, b = 15.521 Å, c = 12.244 Å, V = 1261.2 ų, Z = 2, d _x = 2.255 g/cm³ (II). The thermolysis of the obtained DCS in the hydrogen atmosphere affords two-phase mixtures of limited solid solutions of the metals: hcp for ruthenium-based ones and fcc for Pt or Pd based solutions. On decomposition in the helium atmosphere the products contain a minor amount of RuO₂. For the phases obtained during thermolysis the parameters are determined and the compositions are estimated. The heating of I to 400°C in the helium-air atmosphere yields a nanocrystalline composite Pt+RuO₂ with CSR of ～20 nm.     

Phase equilibria,charge transport,and mass transport in Sr<Subscript>4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>9</Subscript>-“M<Subscript>4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>9</Subscript>” (M = Cd,Cu, Ni,and Zn) systems

Homogeneous fields of Sr_{4 − x} M _x Nb₂O₉ (M = Cd, Cu, Ni, or Zn) solid solutions were determined using powder X-ray diffraction. Phase fields were plotted proceeding from the tolerance factor t and electronegativity ratio $ \bar k_A /\bar k_B $ \bar k_A /\bar k_B with a satisfactory fit of experimental results. Thermogravimetry was used to establish the major kinetic laws of solid-phase synthesis (conversion, rate-controlling stage, and effective activation energy) in (4 − x)SrCO₃ + xMO + Nb₂O₅ powdery mixtures. Direct radiometry was used to determine ⁹⁰Sr, ⁶³Ni, and ⁶⁵Zn self-diffusion coefficients in solid solutions based on the Sr₄Nb₂O₉ phase. Electrical conductivity was measured as a function of temperature for all Sr₄Nb₂O₉-“M₄Nb₂O₉” samples. The conductivity of Sr_{4 − x} M _x Nb₂O₉ (M = Cd, Cu, Ni, or Zn) solid solutions has a mixed ion-electron character.     

Phase formation in Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-K<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-MMoO<Subscript>4</Subscript> (M = Ca,Pb, Ba) systems and the crystal structure of α-KLiMoO<Subscript>4</Subscript>

Solid-phase interactions in Li₂MoO₄-K₂MoO₄-MMoO₄ (M = Ca, Pb, Ba) systems were studied, and the subsolidus regions of these systems were triangulated. The lead and barium systems were studied in a more detailed way to discover that, along KLiMoO₄-K₂M(MoO₄)₂ (M = Pb, Ba), KLiMoO₄-PbMoO₄, and Li₂MoO₄-K₂Ba(MoO₄)₂ quasi-binary sections, there are homogeneity regions reaching 6–11 mol % based on K₂M(MoO₄)₂ and lead molybdate. Triple molybdates are formed in none of the systems, which is verified by experiments on spontaneous crystallization from solution in melt. Crystallization experiments yielded crystals of potassium dimolybdate and simple and double molybdates from the boundary systems. The crystal structure was solved for a hexagonal KLiMoO₄ phase: (Na,K){ZnPO4}, a = 18.8838(7) Å, c = 8.9911(6)Å, Z = 24, space group P6₃, R = 0.065. The structure comprises a three-dimensional tridymite framework built by an alternation of corner-sharing LiO₄- and MoO₄ tetrahedra wherein voids are occupied by potassium cations.     

Synthesis and structure of M[UO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)(NCS)] · 0.5H<Subscript>2</Subscript>O (M = Rb or Cs)

Single crystals of M[UO₂(C₂O₄)(NCS)] · 0.5H₂O (M = Rb (I) or Cs (II)) have been synthesized and studied by X-ray diffraction analysis. The compounds are isostructural, and their crystals are monoclinic with the space group C2/c, Z = 4, and unit cell parameters: a = 9.0624(5) Å, b = 13.1242(7) Å, c = 8.9204(5) Å, β = 98.897(2)°, R = 0.0226 (I); a = 9.3171(3) Å, b = 13.2987(5) Å, c = 9.1151(3) Å, β = 101.0860(10)°, R = 0.0214 (II). The main structural units of the crystals of I and II are the [[UO₂(C₂O₄)(NCS)]^? chains belonging to the crystal-chemical group AK⁰²M¹ (A = UO ₂ ²⁺ , K⁰² = C₂O ₄ ^2? , M¹ = NCS^? of the uranyl complexes. The uranium-containing chains are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere cations and hydrogen bonds involving the water molecules.     

Crystal structure and infrared spectroscopy of MCl<Subscript>2</Subscript>·2CONH<Subscript>3</Subscript> (M = Cu,Mn)

Crystals of MCl₂·2CONH₃ (M = Cu²⁺, Mn²⁺) are synthesized from low-temperature water-formamide solutions and studied by crystal optical, single crystal X-ray diffraction, and infrared spectroscopy methods. The crystal structures of CuCl₂·2CONH₃ and MnCl₂·2CONH₃ are solved by direct methods and refined in the P1triclinic space group, R1= 0.043 and 0.038 for 501 and 686 reflections with F ₀ÃΣ(F₀) respectively. Unit cell parameters for Cu and Mn salts are: a = 3.705(1) Å and 3.685(1) Å, b = 7.049(2) Å and 7.136(2) Å, c = 7.375(2) Å and 7.779(2) Å, 6h =113.57(3)² and 117.17(2)², β = 96.17(3)² and 95.35(2)², γ = 94.85(3)² and 92.23(2)² respectively, Z= 1. In the studied crystal structures, MCl₄O₂ octahedra share Cl-Cl edges and form chains along the [100] direction. This direction corresponds to a morphological elongation of the obtained crystals and orientation of the maximum refractive index. The FT infrared spectra obtained in a range from 4000 cm^?1 to 300 cm^?1 are very close to the spectrum of liquid formamide, but exhibit better resolution of absorption bands.     

Pyrazolate-bridged binuclear zinc complexes Zn<Subscript>2</Subscript>(μ-dmpz)<Subscript>2</Subscript>(Hdmpz)<Subscript>2</Subscript>(OOCR)<Subscript>2</Subscript> (R = Me,Ph; Hdmpz = 3,5-dimethylpyrazole)

Triethylamine reacts with aqueous zinc acetate and the product of its thermolysis in the presence of benzoic acid to yield the complexes [Zn₇(μ₄-O)(μ-OOCMe)₁₀][η-OC(Me)OHNEt₃]₂ (1) and [Zn₂(μOOCPh)₄][η-OC(Me)OHNEt₃]₂ (2), respectively. The reactions of 1 and 2 with 3,5-dimethylpyrazole at room temperature in benzene yield pyrazolate-bridged binuclear complexes Zn₂(μdmpz)₂(Hdmpz)₂(OOCR)₂ (R = Me (3), Ph (4)). The structures of complexes 1–4 have been determined by X-ray crystallography.     

Synthesis and crystal structure of Rb<Subscript>2</Subscript>[(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(SeO<Subscript>4</Subscript>)] · 1.33H<Subscript>2</Subscript>O

The single crystals of Rb₂[(UO₂)₂(C₂O₄)₂(SeO₄)] · 1.33H₂O were synthesized and studied by X-ray diffraction. The crystals are monoclinic, space group P2₁/m, Z= 2, the unit cell parameters: a = 5.6537(8), b = 18.736(3), c = 9.4535(15) Å, β = 98.440(5)°, V = 990.6(3) ų, R ₁ = 0.0506. The main structural units of the crystal are infinite layers of [(UO₂)₂(C₂O₄)₂(SeO₄)]^2?, corresponding to the crystal chemical group A₂K ₂ ⁰² B² (A = UO ₂ ²⁺ , K⁰² = C₂O ₄ ^2? , B² = SeO ₄ ^2? ) of uranyl complexes. The uranium-containing layers are united into a three-dimensional framework through the electrostatic interactions with the outer-sphere rubidium ions and the hydrogen bonding system involving the outer-sphere water molecules.     

Synthesis and structure of trinuclear pyrazolate-bridged acetates M<Subscript>3</Subscript>(μ-dmpz)<Subscript>4</Subscript>(Hdmpz)<Subscript>2</Subscript>(OOCMe)<Subscript>2</Subscript> (M = Zn or Co; Hdmpz = 3,5-dimethylpyrazole)

We discovered that reactions of hydrous cobalt and zinc acetates with 3,5-dimethylpyrazole (Hdmpz) in boiling xylene or toluene or upon the thermolysis of solid precursors (150°C) yield trinuclear pyrazolate-bridged complexes M₃ (μ-dmpz)₄(Hdmpz)₂ (OOCMe)₂(M = Zn or Co). Depending on the crystallization conditions, these complexes contain various solvating molecules (benzene, toluene, or Hdmpz), which influences the character of intramolecular and intermolecular hydrogen bonding, as shown by X-ray crystallography.     

Synthesis,Structure and Solid-Phase Transformations of Fe Nitrosyl Complex Na<Subscript>2</Subscript>[Fe<Subscript>2</Subscript>(S<Subscript>2</Subscript>O<Subscript>3</Subscript>)<Subscript>2</Subscript>(NO)<Subscript>4</Subscript>] · 4H<Subscript>2</Subscript>O

Binuclear iron nitrosyl complex Na₂[Fe₂(S₂O₃)₂(NO)₄] · 4H₂O (I) was synthesized by the reaction of iron(II) sulfate with sodium thiosulfate in the flow of NO gas. According to X-ray diffraction data, the [Fe₂(S₂O₃)₂(NO)₄]^2– anion has binuclear centrosymmetric structure with Fe atoms bonded by the µ-S atoms of thiosulfate groups. The isomeric shift for complex I =0.168(1) mm/s and quadrupole splitting E _Q =1.288 mm/s at T=80 K. When heated, complex I transforms to Na₂[Fe₂(S₂O₃)₂(NO)₄] (II), whose unit cell parameters found by X-ray diffraction method differ from those of complex I. The process of transformation of I to II was studied by calorimetric method. Complex I transforms to complex II without chemical decomposition, which was confirmed by IR and mass spectroscopy data.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 5, 2005, pp. 323–328.Original Russian Text Copyright © 2005 by Sanina, Aldoshin, Rudneva, Golovina, Shilov, Shulga, Martynenko, Ovanesyan.     

Crystal structure and thermal properties of [Au(en)<Subscript>2</Subscript>]<Subscript>2</Subscript>[Cu(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>]<Subscript>3</Subscript>·8H<Subscript>2</Subscript>O

The crystal structure of a double complex salt of the composition [Au(en)₂]₂[Cu(C₂O₄)₂]₃·8H₂O (en = ethylenediamine) at 150 K is determined by single crystal X-ray diffraction. The crystal data for C₂₀H₄₈Au₂Cu₃N₈O₃₂ are: a = 9.1761(3) Å, b = 16.9749(6) Å, c = 13.4475(5) Å, β = 104.333(1)°, V = 2029.43(12) ų, P2₁/c space group, Z = 2, d _x = 2.450 g/cm³. It is demonstrated that the thermal decomposition of the double complex salt in a helium or hydrogen atmosphere affords the solid solution Au_0.4Cu_0.6.     

Sol–Gel Synthesis of Na<Subscript>2</Subscript>O-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> Glasses and their Characterization by NMR,SNMS, and AFM

Sodium aluminophosphate samples with composition 43.8Na₂O12.5Al₂O₃43.8P₂O₅ were prepared by the sol–gel route using different precursors and working in different pH ranges from pH < 1 up to pH > 10. The structures of the gels and of the corresponding glasses were investigated by solid state NMR and compared to that of a glass with the same composition prepared by a traditional melting process. In addition to bulk materials, thin films were deposited by dip coating on silica glasses. Applying secondary neutral mass spectrometry (SNMS), the expected elements and residual carbon were identified. The surfaces of the coatings and fracture surfaces of bulk material were investigated using atomic force microscopy (AFM). Solid state NMR revealed that samples prepared via a lactate route exhibited local Al and P environments closest to that of the melt-prepared glass, with the highest extent of Al-O-P connectivity.     

Synthesis and transport properties of perovskite-like phases (Sr,Ba)<Subscript>4</Subscript>E<Subscript>2</Subscript>Nb<Subscript>2</Subscript>O<Subscript>11 ± δ</Subscript> (E = Mn,Cr, Cu)

Synthesis of (Sr, Ba)₄Э₂Nb₂O_{11 ± δ} where E = Mn, Cr, Cu and solid solution (Sr_1?y Cu_y)_{6 ? 2x} Nb_{2 + 2x} O_{11 + 3x} is performed. By measuring the overall conductance of some solid-solution compositions it is established that the conductance increases with the cubic-lattice parameter and concentration of oxygen vacancies. Values of the conductance in humid air at T < 700°C are shown to increase as compared with dry air. Mass spectrometry analysis confirms the possibility of water incorporation into the complex-oxide structure out of a gas phase. Complex certification of samples of the composition (Sr, Ba)₄E₂Nb₂O₁₁ where E = Mn, Cr, Cu is performed. It is established that the decrease in the overall electroconductance occurs in the series Sr₄Mn₂Nb₂O₁₁ > Ba₄Mn₂Nb₂O₁₁ > Sr₄CrMnNb₂O₁₁ > Sr₄Cu₂Nb₂O₁₁. Investigation of the overall electroconductance in dry and moist atmospheres shows that the effect of humidity exerts no influence on the values of the overall electroconductance. The oxygen-ion constituent of conductance is determined by the Arzhannikov method and is also evaluated from a σ,pO₂ dependence. It is established that the presence of an element with a variable oxidation degree for compositions of the type Sr₄E₂Nb₂O₁₁ leads to an increase in the contribution made by the electronic constituent. In so doing, the magnitude of the oxygen-ion conductance practically does not alter. Thermal and mass spectrometry analyses show that, for the Sr₄E₂Nb₂O₁₁ compositions where E = Mn, Cr, Cu, there occurs no water intercalation into structure, correspondingly, there is observed no appearance of a protonic constituent of conduction.     

Fullerides: heterometallic superconductors with composition M<Subscript>2</Subscript>M′C<Subscript>60</Subscript> (M = K,Rb; M′ = Yb,Lu, Sc)

One- or two-step reactions of potassium and rubidium fullerides with composition M_k C₆₀ (M = K, Rb; k = 3—6) and K₆C₆₀ + m K mixtures (m = 1, 3) with anhydrous salts MCl₃ (M = La, Pr, Nd, Sm, Gd, Tb, Yb, Lu, Y, Sc) and YbI₂ in a toluene—THF medium afforded heterometallic fullerides M_3–nM_nC₆₀ (n = 1—3). Among these compounds, substituted fullerides with composition M₂MC₆₀ (M = Yb, Lu, Sc) display superconducting properties with critical temperatures of 14—20 K.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1623–1628, August, 2004.     

Synthesis and structure of the complex [Mo<Subscript>3</Subscript>(μ<Subscript>3</Subscript>-S)(μ<Subscript>2</Subscript>-S<Subscript>2</Subscript>)<Subscript>3</Subscript>(Et<Subscript>2</Subscript>NCS<Subscript>2</Subscript>)<Subscript>3</Subscript>]I

The structure of tri-μ₂-disulfido-μ₃-thiotris(diethyldithiocarbamato)-S,S′-triangle-trimolybdenum iodide [Mo₃(μ₃-S)(μ₂-S₂)₃(Et₂NCS₂)₃]I was determined. The compound was characterized by differential thermal analysis and IR, Raman, and X-ray electronic spectroscopy.     

Synthesis and crystal structures of [K(H<Subscript>2</Subscript>O)(Piv)]<Subscript>∞</Subscript> and [K<Subscript>2</Subscript>(Phen)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>(Piv)<Subscript>2</Subscript>]<Subscript>∞</Subscript>

A method for the synthesis of potassium pivalates (trimethylacetates) from potassium tert-butoxide and pivalic acid was proposed. The complexes of the formulas [K(H₂O)(Piv)]_∞(I) and [K₂(Phen)(H₂O)₂(Piv)₂]_∞ (II) (Piv denotes the pivalate anion and Phen denotes 1,10-phenanthroline) were obtained and characterized by elemental analysis and IR and ¹H NMR spectroscopy. The crystal structures of complexes I and II were determined using X-ray diffraction. Crystal structure I has a layered motif with two nonequivalent K atoms (C.N.s 5 + 2 and 6). The coordination of phenanthroline in II gives rise to a ribbon motif, the structure containing three nonequivalent K atoms (C.N.s 6, 6 + 1, and 8).     

New double complex salt [PdEn<Subscript>2</Subscript>]<Subscript>3</Subscript>[Rh(NO<Subscript>2</Subscript>)<Subscript>6</Subscript>]<Subscript>2</Subscript> · 2.67H<Subscript>2</Subscript>O: Synthesis,crystal structure,and thermal properties

The crystal structure of the double complex salt (DCS) [PdEn₂]₃[Rh(NO₂)₆]₂ ? 2.67H₂O (I) has been determined by X-ray diffraction. Crystals are triclinic, space group \(P\bar 1\), Z = 4, a = 9.2331(3) Å, b = 9.9136(4) Å, c = 13.7824(5) Å, α = 84.3230(14)°, β = 89.9655(14)°, γ = 66.7272(13)°, V = 1152.19(7) ų, ρ_calcd = 2.141 g/cm³, R = 0.0279. The thermal behavior of complex salt I has been studied in various gas atmospheres. The end product of thermolysis in reductive atmosphere is a mixture of Pd_0.45Rh_0.55 and Pd_0.95Rh_0.05 solid solutions. The end product of thermolysis in an inert atmosphere is a homogeneous Pd_0.6Rh_0.4 solid solution.     

Crystal structure of Ba<Subscript>3</Subscript>[UO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(NCS)]<Subscript>2</Subscript> · 9H<Subscript>2</Subscript>O

Single crystals of Ba₃[UO₂(C₂O₄)₂(NCS)]₂ · 9H₂O are synthesized and studied by X-ray diffraction. The crystals are orthorhombic, space group Fddd, Z = 16, and the unit cell parameters are a = 16.253(3) Å, b = 22.245(3) Å, c = 39.031(6) Å. The main crystal structural units are mononuclear complex groups [UO₂(C₂O₄)₂NCS]^3? of the crystal-chemical family (AB ₂ ⁰¹ M¹ (A = UO ₂ ²⁺ , B⁰¹ = C₂O ₄ ^2? , M¹ = NCS^?) of the uranyl complexes linked into a three-dimensional framework by electrostatic interactions and hydrogen bonds involving oxalate ions and water molecules.