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The KLa(SO4)2·H2O–SrSO4·0.5H2O system was studied by X-ray powder diffraction analysis, differential thermogravimetric analysis, and electronic microscopy. The limits of existence were determined for solid solutions of two types: the ones based on the structure of the hexagonal form α-SrSO4·0.5H2O in the concentration range 10–70 mol % SrSO4·0.5H2O and the ones based on the structure of the orthorhombic form β-SrSO4·0.5H2O in the concentration range 85–100 mol % SrSO4·0.5H2O.

The crystal structures of Ca1.5Mn0.5V2O7 (I) and Ca1.5Cd0.5V2O7 (II) synthesized by the citrate method and by a conventional solid-state reaction, respectively, were determined using X-ray powder diffraction data. It was found that the compound I has a monoclinic crystal structure a = 4.88563(9) Å, b = 11.21279(22) Å, c = 5.69643(11 Å), β = 96.376(7)°, V = 310.132(10) Å3 (space group P21/c), Z = 2). Compound I has a narrow homogeneity region Ca1.5±0.1Mn0.5±0.1V2O7. The vanadate Ca1.5Cd0.5V2O7 crystallizes in the triclinic system with the parameters a = 6.66139(6) Å, b = 6.93019(7) Å, c = 7.02211(6) Å, α = 85.4404(9)°, β = 63.7505(7)°, γ = 82.5515(10)° и V = 288.201(5) Å3 (space group P$\bar 1$, Z = 2). It is one of the formulations of the primary solid solution, formed as a result of the substitution of part of the calcium cations for cadmium cations in Ca2V2O7.

New vanadatogermanates Ca3–xMe2 + xV2GeO12, Ca3Mе2VGe2O12, and Ca3Me2Ge3O12, where Me = Mg, Mn, Co, Ni, Fe, Zn, and x = 0–1, have been synthesized through coupled substitutions of cations in the initial garnets Ca2.5Mn2V3O12 or Ca3Fe2Ge3O12. The unit cell parameters of the synthesized samples have been determined. Probability analysis of the cation distribution in the octahedral positions of the crystal lattice as a function of crystallographic radii has been performed taking into account the spin state of the cations.

The reaction of zinc(ii) acetate hydrate with pivalic acid (HOOCBut− = HPiv) in air at 100 °C afforded the new 1D coordination polymer {Zn(Piv)2}n (1), in which the metal atoms are in a tetrahedral ligand environment. The thermal behavior of the resulting compound and the sublimation and vaporization processes in the temperature range of 430–550 K were studied by differential scanning calorimetry and thermogravimetric analysis. The structure of compound 1 was determined by X-ray powder diffraction.

Superconducting properties of new heterofullerides synthesized for the first time AnMmHgxC60 (A = K, Rb, Cs; M = Be, Mg, B, Al, Ga, In; n = 1, 2; m = 1, 2; x ≪ 1) were investigated at low temperatures. The low frequency inductive method was used to detect a superconducting transition. All the samples were studied by X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR), electron spin resonance (ESR), and Raman scattering. It is found that most of the superconducting heterofullerides are potassium heterofullerides. For the fulleride K2GaHgxC60 the critical temperature of the superconducting transition is Tc = 20 K. Indium and boron heterofullerides are not superconductors. The synthesis of heterofullerides via amalgams (Hg–K–Mg, Hg–Rb–Al) gives rise to two different superconducting phases.

Kinetic analysis of the thermolysis of samarium pivalate [Sm2(μ2-OOCCMe3)4(OOCCMe3)2(HOOCCMe3)6] · HOOCCMe3 (1) was carried out (the input data were differential scanning calorimetry (DSC) and thermogravimetry data), and a mathematic model of the process was developed that allowed us to optimize (by calculation) the conditions for formation of {Sm(OOCCMe3)3} n (2) samarium tris-pivalate via thermal decomposition of complex 1. The results of the thermal study of samarium and gadolinium tris-pivalates in the temperature range of −50…+50°C are reported. Specific anomalies were found in the DSC curves and heat capacity versus temperature curves in the temperature range of 0–50°C.

Electrooxidation of dissolved CO and methanol at platinum-tin electrodes with different phase composition (a two-phase Sn/Pt-catalyst, Pt-Sn alloy, and Pt3Sn intermetallic compound) is studied. All studied catalysts show higher catalytic activity in the CO oxidation at lower potentials (0.3–0.5 V against reversible hydrogen electrode (RHE)), as compared with platinum; no catalysis is observed at higher potentials (0.7 V); moreover, inhibiting is observed in some cases. The catalyst with the most strongly ordered structure (Pt3Sn) demonstrated the highest catalytic activity; however, it appeared being less stable against oxidation at potentials more positive than 1.0 V. Catalytic effects were practically absent in the CO-adsorbate oxidation process. The sequence of catalyst activities in the methanol oxidation process differed from that in the CO oxidation; in particular, Pt3Sn appeared being the least active. The observed difference can be associated with the difference in the CO and methanol adsorption mechanisms. The effect of the carbonaceous support dispersion on the current-voltage curves is discussed.

Methods of synthesis of binuclear pivalate complexes L2Ln2(μ-O,η2-OOCCMe3)2(μ2-O,O′-OOCCMe3)2(η2-OOCCMe3)2, where Ln = Sm, Eu, Gd, or Er and L = 2,2′-dipyridyl (Bipy) or 1,10-phenanthroline (Phen), from the corresponding binuclear complexes Ln2(μ2-OOCCMe3)4(OOCCMe3)2(HOOCCMe3)6 · HOOCCMe3(I–IV), as well as of coordination polymers {Ln(OOCCMe3)3} n , were suggested. The compounds were characterized by X-ray crystallography and X-ray powder diffraction and their magnetic properties, solid-phase thermolysis, and the phase composition of solid decomposition products were studied. The structures of the metal carboxylate core and surrounding ligands were shown to have an effect on the thermal stability of the complexes. The luminescence properties of the Eu(III) complexes were analyzed.

The structure and electron properties of NanC60 (n = 2, 3) sodium fullerides synthesized from simple compounds in toluene were studied. It was shown that Na2C60 fulleride forms a face-centered cubic lattice at temperatures above 300 K. As the temperature is lowered, the phase transition to a structure with a simple cubic lattice takes place. The temperature dependences of the properties of Na3C60 with a more complex structure exhibit features that are presumably due to sodium atom redistribution in the Na3C60 fulleride lattice and the formation of sodium ion clusters.

New heterofullerides Cs2MC60, CsM2C60, Rb2MC60, K2MC60, and KM2C60 (M = Be, Mg, Ca, Ba) have been synthesized; the temperature dependences of the magnetic susceptibilities of these compounds in the temperature range from 4.2 to 297 K have been measured. Among these heterofullerides, K2MgC60, KMg2C60, K2CaC60, K2BeC60, and Rb2BeC60 pass to the superconducting state at temperatures Tc = 13–24.3 K. The paramagnetic electronic states of the compounds have been studied by EPR at temperatures of 105–300 K, which shows the existence of two types of paramagnetic centers, related to oxygen defects and conduction electrons.

Complex oxides A 3 M 2 O 8 (A = Sr, Ba; M = P, As, V) with the palmierite structure (space group R -3 m (no. 166), Z = 3) [1‐6] are considered as promising ceramics, ionic conductors, and membrane materials. In the structures of these compounds, the A cations occupy 3 a and 6 c positions with coordination numbers (CN) of 6 and 10, respectively. The M cations occupy 6 c positions (CN = 4) and the O atoms are in 6 c and 18 h positions. The A 3 M 2 O 8 oxides are quite stable with respect to heterovalent replacement in the cationic (A, M) and anionic sublattices; for example, Ba 3 (W,Nb) 2 O 8 , Ba 3 Mo 2 O 6 N 2 , and Ba 3 W 2 O 6 N 2 were obtained [7, 8]. The double orthovanadates A 2 Ln 2/3 (VO 4 ) 2 with the palmierite structure were found in the A 3 (VO 4 ) 2 –LnVO 4 binary systems, where A = Ca, Sr, Ba; Ln = La, Nd [9, 10]. In this group of compounds, 6 c positions are statistically occupied by two sorts of cations, 0.3333 Ln 3+ and 0.5 A, while 3 a positions contain only one sort of cation (A). These compounds can be considered as the limiting compositions of solid solutions formed upon replacement of A atoms in the orthovanadates A 3 (VO 4 ) 2 , where A = Ca, Sr, Ba. Thus, if the valences are balanced, one can expect the formation of stable compounds upon any heterovalent substitution in the sublattices, which may be either complete or defective. However, no data on the A 3 M 2 O 8 oxides with heterovalent substitutions in the 3 a position have been reported. In this work, we report the results of synthesis and study of the structural and electronic properties of a new orthovanadate Sr 2 Bi 2/3 (VO 4 ) 2 in which Sr → Ba heterovalent substitution in the 3 a position is implemented for the first time. The compound was prepared by solid-phase synthesis from special purity grade bismuth and vanadium(V) oxides and strontium carbonate. The reactants were mixed and subjected to stepwise annealing in the temperature range 550–1100°e with a temperature rise by 100°e every 12‐15 h. The samples were pressed into

A coordination polymer of the general formula [Co(OOCCMe3)2]n (2) was prepared by mild thermolysis of the coordination polymer of variable composition [(HOOCCMe3)xCo(OH)n(OOCCMe3)2−n ]m, the dinuclear cobalt complex Co2(μ-H2O)(OOCCMe3)4(HOOCCMe3)4, the tetranuclear cobalt cluster Co4(μ3-OH)2(OOCCMe3)6(HOEt)6, and the hexanuclear cluster [Co6(μ4-O)2(μn-OOCCMe3)10(C4H8O)3(H2O)]·1.5(C4H8O) (7) in organic solvents. In the crystal, the polymer has a chain structure. Unlike thermolysis of cobalt pivalates, thermolysis of the dinuclear complex Ni2(μ-H2O)(OOCCMe3)4(HOOCCMe3)4 gave rise to the hexanuclear complex Ni6(μ2-OOCCMe3)6(μ3-OOCCMe3)6 (3). The magnetic properties of compound 2 are substantially different from those of 3. Compound 2 undergoes the magnetic phase transition into the ordered state at T c = 3.4 K (H = 1 Oe), whereas compound 3 exhibits antiferromagnetic properties. Solid-state decomposition of polymeric cobalt carboxylate 2 (below 350 °C) afforded the octanuclear cluster Co8(μ4-O)2(μ2-OOCCMe3)6(μ3-OOCCMe3)6 (9) as the major product, which sublimes without decomposition. Decomposition of 3 gave nickel oxide as the final product. Pivalates 2 and 3 reacted with 2,3-lutidine in acetonitrile at 80 °C to form the isostructural dinuclear complexes (2,3-Me2C5H3N)2M2(μ-OOCCMe3)4 (M = Co or Ni). The structures of compounds 3 and 7 were established by X-ray diffraction. The structure of polymer 2 was determined by powder X-ray diffraction analysis.

The crystal structure of anhydrous K4V2O7 (I) is determined by powder X-ray diffraction. The compound crystallizes in the monoclinic system (a = 10.222(1) A, b = 6.2309(8) A, c = 7.282(1) A, β = 101.31(1)°, space group C2/m, Z = 2). The structure contains layers of isolated V2O7 pyrovanadate groups separated by layers of potassium cations. The hydration and dehydration of I are studied by thermal analysis and high-temperature X-ray diffraction. The dehydration is accompanied by decomposition of the starting crystal hydrate to give intermediate compounds. Anhydrous compound I undergoes a reversible phase transition at 740°C. The high-temperature phase is assumed to have a hexagonal unit cell (a = 6.169(4) A, c = 15.72(1) A, Z = 2).

Stability of the hcp modification of fullerite C60 under heating, compression, and mechanical grinding was studied. It was established that uniaxial load and mechanical grinding caused transition of the hcp modification into more stable fcc modification, while no transition was observed upon heating or hydrostatic pressure. The results were discussed in terms of the theory of the deformation of solids.

The chemical transformations involved in the synthesis of the NASICON-type compound LiZr2(PO4)3 were studied by thermogravimetry and x-ray diffraction. The results demonstrate that, during heat treatment of a 3Zr(HPO4)2 · 2H2O + Li2CO3 + ZrO2 mixture, the formation of the NASICON phase begins at 600°C. Further heating, however, leads to the concurrent formation of zirconium diphosphate and uncontrolled lithium losses because of the high volatility of Li compounds. A well-crystallized, high-conductivity NASICON phase is formed only above 1100°C. Phase-pure LiZr2(PO4)3 can only obtained by a two-step procedure.

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 La1 − xSr2 + x(GeO4)(V1 − xMoxO4) (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.

Phase equilibria in the Ba3(VO4)2-K2Ba(MoO4)2 and Pb3(VO4)2-K2Pb(MoO4)2 systems have been investigated. In the first system, a continuous series of substitutional solid solutions with the palmierite structure is formed, and in the second one, the polymorphic transition in lead orthovanadate at 100°C restricts the extent of the palmierite-type solid solution to 10–100 mol % K2Pb(MoO4)2.

Samples of the hexagonal close-packed phase (h.c.p.) of fullerite C 60 with a low (less then 7%) content of more stable face-centered cubic (f.c.c.) phase were synthesized using cryoextraction with n -hexane. X-Ray diffraction analysis and thermogravimetry were applied for characterization of the samples. The role of n -hexane in the formation of the h.c.p. structure is discussed.

LinC60 fullendes were prepared by high-pressure solid-state reactions and characterized by IR spectroscopy and x-ray diffraction. The results are interpreted in terms of a sequence of phase transformations induced by Li incorporation. At low Li contents, 2

LinC60 fullendes were prepared by high-pressure solid-state reactions and characterized by IR spectroscopy and x-ray diffraction. The results are interpreted in terms of a sequence of phase transformations induced by Li incorporation. At low Li contents, 2