- Electrical transport in the system Li2SO4-mLi2MoO4-2mLi3VO4
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The electrical conductivity (σ) and thermoelectric power (S) of three compounds (m = 0, 0.5 and 1) in the system Li2SO4-mLi2moO4-2mLi3 VO4 is reported from 500°C to the melting point. All three solids show a superionic phase just below their melting point. In this phase, σ decreases but activation energy and span of superionic phase increases for compounds with larger m. The phase transition temperature (Tp) from normal to superionic phase decreases with m. Below Tp, the order of σ is reversed. It increases with m but becomes mixed with the dominant ionic part.
- Lal,Gaur,Pathak
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- Structure and properties of Li2–2xMg2+x(MoO4)3 crystals activated by copper ions
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By the low-gradient ?zochralski method, both undoped and copper ion activated Li2–2xMg2+x(MoO4)3 crystals are grown. The charge state and structural position of impurity copper ions are determined using EPR. Investigations of the luminescence properties reveal that luminescence with a maximum at λ = 520 nm is observed for Li2–2xMg2+x(MoO4)3 crystals. A decrease in the temperature increases the intensity of this luminescence. It is found that the doping of Li2–2xMg2+x(MoO4)3 crystals with copper ions also increases the luminescence intensity with a maximum at λ = 520 nm. It is supposed that cation vacancies, which provide the charge compensation when copper ions substitute for lithium ions, are responsible for the luminescence.
- Ryadun,Trifonov,Nadolinny,Pavlyuk,Rakhmanova
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- Thermochemistry of lithium chromate Li2CrO4(cr) and lithium molybdate Li2MoO4(cr)
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The standard molar enthalpies of formation ΔfH degm at the temperature T = 298.15 K of Li2CrO4(cr) and Li2MoO4(cr) have been determined using an isoperibol solution calorimeter.The value of ΔsolHinfinite m for Li2CrO4(cr) in water at T = 298.15 K was found to be -(45.77 +/- 0.29) kJ * mol-1 and was used to obtain ΔfH degm(298.15 K) as -(1393.7 +/- 0.3)kJ * mol-1.The ΔsolH degm of Li2MoO4(cr) and of -3) at T = 298.15 K were used to obtain a value of -(1519.2 +/- 2.2)kJ * mol-1 for Δf H degm for Li2MoO4(cr).
- Shukla, N.K.,Prasad, R.,Roy, K.N.,Sood, D.D.
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- Temperature induced phase transformations on the Li2MoO4 system studied by Raman spectroscopy
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The present research reports results of lattice dynamics calculations and temperature-dependent Raman scattering study of the dilithium molybdate system, Li2MoO4, in the 25–600?°C temperature range. The effects of the temperature duly produced gradual changes, associated with the disorder and anharmonic effects followed by thermodynamic instability, leading the structure to a phase transformation. Calorimetric measurements up to 1000?°C corroborated that the crystal structure experienced gradual modifications, characterized by changes in the DSC base line. These stated thermal events as well as the changes in the profile of the Raman spectra, suggested that a phase transformation is connected with tilting and/or rotations of the MoO4 tetrahedron leading to a disorder in the MoO4 sites. The observation of one exothermic peak on the DSC curve at about 702?°C is related with the melting in the sample. The experimental results were discussed based on the mode assignments performed by using lattice dynamics calculations from where we predicted both wavenumbers and atomic displacements.
- Saraiva,Paraguassu,Freire,Ramiro de Castro,de Sousa,Mendes Filho
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- Synthesis and electrical properties of ternary molybdates Li 3Ba2R3(MoO4)8 (R = La-Lu, Y)
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X-ray diffraction and differential-thermal analyses were used to study the phase relations in the subsolidus region of the system Li2MoO 4-BaMoO4-R2(MoO4)3. The temperature dependence of th
- Kozhevnikova,Kopylova
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- Electrochemical behavior of submicron Li2MoO3 as anodes in lithium-ion batteries
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Theoretically, Li2MoO3 can serve as cathodes as well as anodes in lithium-ion batteries because Mo element in the compound is at the intermediate valence state. However, to date, little work has been devoted to the study of Li2MoO3 as anodes in lithium-ion batteries. In the paper, submicron Li2MoO3 is synthesized via simple liquid chemical reaction, followed by thermal reduction in H2/Ar (5:95 v/v) atmosphere. The as-prepared Li2MoO3 is polycrystalline with layered structure. At a current density of 100 mA g-1 over a voltage window of 0-3.0 V, the compound delivers a first discharge capacity of 836 mAh g-1 with a high initial coulombic efficiency of 94.5%. After 200 cycles at a current density of 300 mA g-1 over a voltage window of 0-3.0 V, a discharge capacity of 654 mAh g-1 is preserved. At a high current density of 1600 mA g-1, the composite still keeps a discharge capacity of 489 mAh g-1. The high first charge-discharge efficiency is ascribed to its self-compensation ability of Li2MoO3 for the first irreversible capacity loss.
- Li, Dan,He, Hongyan,Wu, Ximin,Li, Mingqi
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- Synthesis and X-ray diffraction and IR spectroscopy studies of ternary molybdates Li3Ba2R3(MoO4) 8 (R = La-Lu, Y)
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Ternary molybdates Li3Ba2R3(MoO 4)8 (R = La-Lu, Y) were synthesized by the solid-phase method. Their unit cell parameters were determined and IR spectra were assigned. The compounds are isostructural
- Kozhevnikova,Kopylova
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- Electronic and ionic conduction in some simple lithium salts
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The electrical conductivity (?) and thermoelectric power (S) of solidifed melt samples of Li2MoO4, Li2WO4 and Li2SO4 are presented in the temperature range 415 K to melting point of each compound. The ratio of ionic to electronic contribution to ? has been obtained with the help of a time-dependence study of dc electrical conductivity. It has been shown that the Li2MoO4 electronic contribution to ? remains high up to its melting point (about 8% just below the melting point) and it shows no superionic phase. However, in Li2WO4 and Li2SO4 a superionic phase is obtained in which the ionic contribution to ? is more than 99.99%. However, in normal ionic (or α) phase it is small and decreases with decreasing temperature. Separate temperature variations of ionic (?i) and electronic (?e) conductivities are presented and the conduction mechanisms are discussed. It is shown that ionic conduction in the β-phase is dominated by Schottky type defects.
- Lal, H. B.,Gaur, Kanchan,Pathak, A. J.
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- Phase formation in Li2MoO4-K2MoO 4-MMoO4 (M = Ca, Pb, Ba) systems and the crystal structure of α-KLiMoO4
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Solid-phase interactions in Li2MoO4-K 2MoO4-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-K 2Ba(MoO4)2 quasi-binary sections, there are homogeneity regions reaching 6-11 mol % based on K2M(MoO 4)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 KLiMoO 4 phase: (Na,K){ZnPO4}, a = 18.8838(7) ?, c = 8.9911(6)?, 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.
- Gudkova,Solodovnikova,Solodovnikov,Zolotova,Kurat'Eva
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- Synthesis and luminescence properties of a Li3BaCaY3(MoO4)8:Er3+ phosphor with a layered scheelite-like structure
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A Li3BaCaY3(MoO4)8:Er3+ phosphor with a scheelite-like structure (sp. gr. C2/c) has been synthesized and its luminescence properties have been studied. The phosphor has been characterized by X-ray dif
- Kozhevnikova
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- Formation laws for scheelite-like triple molybdates LiMLn 2(MoO4)4
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The size factor is shown to be decisive in the structure formation of triple molybdates LiMLn2(MoO4)4. The LiMLn 2(MoO4)4 compounds (where M is a large alkali metal) are formed when 0.48 ? r M + - r Ln 3+ 0.60 ?. Pleiades Publishing, Inc., 2006.
- Basovich,Khaikina
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- Raman and Density Functional Theory Studies of Li2Mo4O13 Structures in Crystalline and Molten States
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The Li2Mo4O13 melt structure and its Raman spectral characteristics are the key for establishing the composition-structure relationship of lithium molybdate melts. In this work, Raman spectroscopy, factor group analysis, and density functional theory (DFT) were applied to investigate the structural and spectral details of the H-Li2Mo4O13 crystal and a Li2Mo4O13 melt. Factor group analysis shows that the crystal has 171 vibrational modes (84Ag + 87Au), including three acoustic modes (3Au), six librational modes (2Ag + 4Au), 21 translational modes (7Ag + 14Au), and 141 internal modes (75Ag + 66Au). All of the Ag modes are Raman-active and were assigned by the DFT method. The Li2Mo4O13 melt structure was deduced from the H-Li2Mo4O13 crystal structure and demonstrated by the DFT method. The results show that the Li2Mo4O13 melt is made up of Li+ ions and Mo4O132- groups, each of which is formed by four corner-sharing MoO3?/MoO2?2 tetrahedra (? = bridging oxygen). The melt has three acoustic modes (3A) and 54 optical modes (54A). All of the optical modes are Raman-active and were accurately assigned by the DFT method.
- Wan, Songming,Zhang, Bo,Yao, Yanan,Zheng, Guimei,Zhang, Shujie,You, Jinglin
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- X-ray Powder Diffraction Study of Molybdenum Oxides Formed From the Thermal Reactions of MoS2, MoS2/LiF, and MoS2/Ag in Air
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MoS2 can generate useful molybdenum oxides by thermally reacting with LiF or Ag nanoparticles (NPs). MoS2 easily loses sulfide and reacts with oxygen gas upon heating in air to give orthorhombic molybdenum trioxide, α-MoO3. Morphological changes of α-MoO3 from 500 to 900°C were investigated using X-ray powder diffraction and scanning electron microscope. The strong diffraction peaks of the (020), (040), and (060) planes at 800°C revealed highly anisotropic growth of the oxides with a layered crystal structure. In the presence of LiF, MoS2 reacts with oxygen gas to generate Li2MoO4 and MoO2, depending on the LiF concentration. In the presence of Ag NPs, the thermal reactions of MoS2 at 800 and 900°C give silver molybdates Ag2Mo2O7 and Ag2MoO4, respectively. These results demonstrate that MoS2 is an important precursor for generating useful molybdenum oxides on the surface of inert substrates without requiring sophisticated, expensive equipment.
- Kim, Youhyuk,Lee, So-Ram
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- Spontaneous formation of crystalline lithium molybdate from solid reagents at room temperature
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Lithium molybdate has been prepared by grinding LiOH·H2O with MoO3 in air at room temperature. X-Ray powder diffraction data show that the formation of highly crystalline Li2MoO4 is largely complete after 10 min. The phenacite structure of this material is the same as that derived from an X-ray diffraction study of a single crystal obtained from aqueous solution [R3; a = 14.3178(14), c = 9.5757(9) ]. Anhydrous lithium hydroxide fails to give the same reaction indicating that the water of crystallisation of LiOH·H2O is a vital component in this rapid synthesis. Differential scanning calorimetry measurements show that this reaction can proceed spontaneously between the two stable solid reagents at sub-ambient temperatures and is driven by the liberation of water from the crystalline lattice. Lithium molybdate prepared in this manner has significantly smaller and more regularly shaped particles than samples prepared by other synthetic methods. The Royal Society of Chemistry.
- Yip, Thomas W. S.,Cussen, Edmund J.,Wilson, Claire
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- Microwave dielectric ceramics in Li2O-Bi2O 3-MoO3 system with ultra-low sintering temperatures
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A series of compounds in the Li2O-Bi2O 3-MoO3 ternary system were investigated with regard to the preparation, phase composition, microwave dielectric properties, and chemical compatibility with silver (Ag) and aluminum (Al) electrodes. All the ceramics in this work have sintering temperatures lower than 750°C. The sintering behaviors and microwave dielectric properties of three single phases Li 2MoO4, (Li0.5Bi0.5)MoO4, and Li8Bi2Mo7O28 bulk ceramics, were of particular focus in this investigation. The Li2MoO4 ceramic can be sintered to a high density at 540°C/2 h with a relative permittivity ~5.5, a Q × f value of 46 000 GHz, and a temperature coefficient of resonant frequency (TCF) of ~-160 ppm/°C. The (Li 0.5Bi0.5)MoO4 ceramic has a scheelite structure and the largest relative permittivity of 44.4 among the ceramics studied in this work with a sintering temperature around 560°C, a Q × f value of 3200 GHz, and a large positive TCF of ~+245 ppm/°C. The Li 8Bi2Mo7O28 ceramic could be sintered at 540°C and has a relative permittivity of 13.6, a Q × f value of 8000 GHz, and a small negative TCF value of ~-59 ppm/°C. From the X-ray diffraction analysis of cofired ceramics, the Li2MoO4 ceramic does not react with either Ag or Al powders. The Li8Bi 2Mo7O28 ceramic reacts with Ag but not with Al at its densification temperature. The (Li0.5Bi0.5)MoO 4 ceramic was found to strongly react with Ag powder and to a limited extent with Al powders. From this study, the Li2O-Bi 2O3-MoO3 ternary system has a number of attractive new materials with low sintering temperatures, high-performing microwave dielectric properties, chemical compatibility with both Ag and Al metal electrodes, nontoxicity, and low-cost constituents. All these materials can be included in the new field of ultra-low-temperature cofiring dielectrics for multilayer applications.
- Zhou, Di,Randall, Clive A.,Wang, Hong,Pang, Li-Xia,Yao, Xi
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- Synthesis and structure of a 3D porous network containing aromatic 1D chains of Li6 rings: Experimental and computational studies
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A bimetallic 3D network containing 1D chains of Li6 unit rings has been synthesized by using a molybdenum containing metalloligand and the DFT calculations reveal that the rings are aromatic in behavior and resemble the corresponding hydrocarbon analogues.
- Deb, Dibakar,Giri, Santanab,Chattaraj, Pratim K.,Bhattacharjee, Manish
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- Thermodynamic Properties of M2EO4, M2MoxO3x + 1 and Double Chromates (M = Li, Na, K, Rb, Cs; E = Cr, Mo, W)
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The phase transition temperatures of chromates and molybdates of certain alkali metals, and the melting temperature and enthalpy of polymorphic transformations for tungstates, are determined by means of thermal analysis. Enthalpies of dissolution of rubidium and cesium chromates in water and enthalpies of dissolution of alkali metal tungstates in a melt at 923 K are measured via calorimetry. Standard enthalpies of formation of sought chromates are calculated. The linear correlations between the enthalpies of formation of sulfates, selenates, chromates, tungstates, and molybdates are established, and a linear correlation within ? (ΔGo ox)-1-(ΔMV)ox)?1 coordinates is found for isopolymolybdates.
- Suponitskiy, Yu. L.,Zolotova,Dyunin,Liashenko
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- Synthesis and study of Li3BaSrR3(MoO 4)8 compounds (R = La-Lu, Y) with stratified sheelite structure
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Possibility of substituting barium ions with strontium ions in the stratified sheelite structure of Li3Ba2R 3(MoO4)8 (sp. gr. C2/c) was examined. The molybdates Li3BaSrR3(MoOsub
- Kozhevnikova,Kopylova
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- Optical and AC conductivity studies on Li2-xRbx MoO4 (xu202f=u202f0, 0.5, 1) compounds
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In this work, we are interested in the new compounds Li1.5Rb0.5MoO4 preparation by the solid state method. Also, we present a comparative study with LiRbMoO4 and Li2MoO4. The X-ray powder diffraction indicates that these compounds crystallize at room temperature in the monoclinic, orthorhombic and trigonal systems with the P21, Pcab and R-3 space groups, respectively. The shapes of the grains for these ceramics were observed by means of scanning electron microscopy (SEM) images. The Tauc model was used to determine the optical gap energy (4, 4.3 and 3.9 ev) and the urbach energies (1.51, 0.35 and 1.14 ev) of our compounds. The electric and dielectric proprieties of Li1.5Rb0.5MoO4 have been studied. We carried out complex impedance spectroscopy in the frequency range 200 Hz-5 MHz at different temperatures (575–723 K). The complex impedance diagram showed a single semicircle, implying that the response originates corresponding to the grains. As a result, an electrical equivalent circuit has been proposed. The spectra follow the Arrhenius law with two energies of activation 1.58 eV for impedance measurements and 1.25 eV for that of modulus. The alternative current (AC) electrical conduction of the three compounds is governed by the overlapping large polaron tunneling (OLPT).
- Ben Nasr,Mahmoud,Boschini,Ben Rhaiem
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- Standard molar enthalpy of formation of lithium molybdates (Li2 MonO3n+1 with n=1, 2, 3 and 4) at 298.15 K
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Four compounds in the system Li2O-MoO3, namely, Li2 MoO4(c), Li2Mo2O(c), Li2Mo3O10(c) and Li2 Mo4O13(c) were synthesized an
- Tangri,Venugopal,Bose
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- Phase formation in the Li2MoO4-A2MoO 4-NiMoO4 (A = K, Rb, Cs) systems, the crystal structure of Cs2Ni2(MoO4)3, and color characteristics of alkali-metal nic
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The subsolidus regions of the Li2MoO4-A 2 + MoO4-NiMoO4 (A+ = K, Rb, Cs) systems at 510°C have been triangulated by the intersecting-joins method. The A2MoO4/sub
- Zolotova,Solodovnikova,Ayupov,Solodovnikov
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- Li4/3Ni1/3Mo1/3O2 – LiNi1/2Mn1/2O2 binary system as high capacity positive electrode materials for rechargeable lithium batteries
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A binary system of x Li4/3Ni1/3Mo1/3O2 – (1–x) LiNi1/2Mn1/2O2 is studied as high-capacity positive electrode materials for rechargeable lithium batteries. Structural and electrochemical properties of oxides with different compositions in this binary system are examined. Mo ordering is retained for 1 ≤ x ≤ 1/3 with a monoclinic symmetry and disappears for x ≤ 1/6 with a rhombohedral symmetry. Compared with Li4/3Ni1/3Mo1/3O2, partial substitution of Mn for Mo lead to the improvement of reversible capacity and reduction of polarization. For Li6/5Ni2/5Mn1/5Mo1/5O2 (x = 1/3) and Li9/8Ni7/16Mn5/16Mo1/8O2 (x = 1/6), high reversible capacities of around 200 mAh g?1 are obtained. Improved cycling performance is achieved through the optimization of voltage ranges. Further structural characterization by ex–situ XRD reveals that the improved reversibility for the Mn-substituted samples mainly results from the suppression of Mo migration during cycling, probably associated with partial oxygen loss.
- Zhao, Wenwen,Yamaguchi, Kazuma,Sato, Takahito,Yabuuchi, Naoaki
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- Phase formation in the systems Li2MoO4-K 2MoO4-Ln2(MoO4)3 (Ln=La, Nd, Dy, Er) and properties of triple molybdates LiKLn2(MoO 4)4
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Subsolidus phase relations in the systems Li2MoO 4-K2MoO4-Ln2(MoO4) 3 (Ln=La, Nd, Dy, Er) were determined. Formation of LiKLn 2(MoO4)4 was confirmed in the systems with Ln=Nd, Dy, Er at the LiLn(MoO4)2-KLn(MoO4) 2 joins. No intermediate phases of other compositions were found. No triple molybdates exist in the system Li2MoO4-K 2MoO4-La2(MoO4)3. The join LiLa(MoO4)2-KLa(MoO4)2 is characterized by formation of solid solutions. Triple molybdates LiKLn 2(MoO4)4 for Ln=Nd-Lu, Y were synthesized by solid state reactions (single phases with ytterbium and lutetium were not prepared). Crystal and thermal data for these molybdates were determined. Compounds LiKLn2(MoO4)4 form isostructural series and crystallized in the monoclinic system with the unit cell parameters a=5.315-5.145 A, b=12.857-12.437 A, c=19.470-19.349 A, β=92.26-92.98°. When heated, the compounds decompose in solid state to give corresponding double molybdates. The dome-shaped curve of the decomposition temperatures of LiMLn2(MoO4)4 has the maximum in the Gd-Tb-Dy region. While studying the system Li2MoO 4-K2MoO4-Dy2(MoO4) 3 we revealed a new low-temperature modification of KDy(MoO 4)2 with the triclinic structure of α-KEu(MoO 4)21 (a=11.177(2) A, b=5.249(1) A, c=6.859(1) A, α=112.33(2)°, β=111.48(1)°, γ=91.30(2)°, space group P1, Z=2).
- Basovich,Khaikina,Solodovnikov,Tsyrenova
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- Phase formation in the Li2MoO4K2MoO 4In2(MoO4)3 system and crystal structures of new compounds K3InMo4O15 and LiK2In(MoO4)3
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XRD study of solid-phase interaction in the Li2MoO 4K2MoO4In2(MoO4) 3 system was performed. The boundary K2MoO 4In2(MoO4)3 system is an non-quasibinary join of the K2OIn2O3MoO 3 system where a new polymolybdate K3InMo 4O15 isotypic to K3FeMo4O 15 was found. In the structure (=33.2905(8), b=5.8610(1), c=15.8967(4) A, β=90.725(1)°, sp. gr. C2/c, Z=8, R(F)=0.0407), InO6 octahedra, Mo2O7 diortho groups and MoO4 tetrahedra form infinite ribbons {[In(MoO4) 2(Mo2O7)]3-}∞ along the b-axis. Between the chains, 8- to 10-coordinate potassium cations are located. A subsolidus phase diagram of the Li2MoO4K 2MoO4In2(MoO4)3 system was constructed and a novel triple molybdate LiK2In(MoO 4)3 was revealed. Its crystal structure (a=7.0087(2), b=9.2269(3), c=10.1289(3) A, β=107.401(1)°, sp. gr. P2 1, Z=2, R(F)=0.0280) contains an open framework of vertex-shared MoO4 tetrahedra, InO6 octahedra and LiO5 tetragonal pyramids with nine- and seven-coordinate potassium ions in the framework channels. 2012 Elsevier Inc.
- Khal'Baeva, Klara M.,Solodovnikov, Sergey F.,Khaikina, Elena G.,Kadyrova, Yuliya M.,Solodovnikova, Zoya A.,Basovich, Olga M.
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- Role of native and impurity defects in optical absorption and luminescence of Li2MoO4 scintillation crystals
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The Li2MoO4 crystals have been considered as perspective cryogenic scintillation materials to be used in elementary particle physics experiments related to dark matter search and properties of neutrino. Since the crystals may be used as cryogenic scintillators, the native vacancies, uncontrolled impurities and other defects play the key role in worsening of their scintillation characteristics. The paper presents complex experimental and computational studies of the electronic structure and optical properties of Li2MoO4 crystals. The studies are aimed to explain peculiarities of the optical (luminescence) properties of Li2MoO4 using the electronic structure results obtained for a wide range of point defects and their combinations. For investigations, several samples of Li2MoO4 with different defectiveness were grown using Czohralski method and characterized by SEM and ICP-OES technique. Luminescence emission spectra of the samples under X-ray and laser excitations, optical and IR absorption spectra, TSL characteristics of the samples were recorded and analyzed. Ability to incorporate some gases was examined by measuring absorption spectra after one-year storage of the samples at ambient conditions. The electronic structures of several kinds of point defects (natural vacancies, iso- and aliovalent cationic and anionic substitutions, interstitial ions and molecular groups) in Li2MoO4 were calculated using the DFT-based plane-wave pseudopotential method. Geometries of lattice relaxations around defects, partial densities of states and energies of defect formation were calculated and analyzed together with experimental results. Performed analysis allowed making several conclusions regarding the origin of spectral components of intrinsic and defect-related luminescence, formation of defect-related bands in the optical and IR absorption spectra, dependence of TSL characteristics on sample defectiveness. It was found that isovalent cationic substitutions on lithium positions are presented in substantial concentrations in the Li2MoO4 samples and such defects form shallow traps which can affect scintillation characteristics in cryogenic experiments. Substantial effect of gases inclusions on the optical characteristics of crystals can be related to the peculiarity of the crystal lattice structure - the presence of empty channels , which can incorporate molecular objects like H2O, -CH3 or -OH.
- Hizhnyi, Yu.,Borysyuk,Chornii,Nedilko,Tesel'ko,Dubovik,Maksymchuk,Tupitsyna,Yakubovskaya,Androulidaki,Klyui
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- Cathode active material, cathode and lithium battery containing the material and preparation method thereof
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A cathode active material, a cathode including the cathode active material, a lithium battery including the cathode, and a method of preparing the cathode active material, the cathode active material including a lithium-containing metal oxide and an organic material coated on the lithium-containing metal oxide, the organic material including an acrylate or methacrylate organic material including an alkyleneglycol unit.
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- Phase Diagrams for M2MoO4-CdMoO4 Systems
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Phase equilibria in the M2MoO4-CdMoO4 systems with M = Li, Na, Ag, K, Tl, Rb, or Cs are studied by X-ray diffraction, thermal, and crystal-optical analyses. Phase diagrams are mapped for the M2MoO4-CdMoO4 quasi-binary joins. For better understanding of morphotropic transitions in the series of double molyb-dates of univalent metals and cadmium, comparative analysis of the relevant phase diagrams is made.
- Tsyrenova,Gypylova,Solodovnikov,Zolotova
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p. 1905 - 1911
(2008/10/08)
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- Electrospray mass spectral study of isopolyoxomolybdates
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Electrospray mass spectrometry (ESMS) has been performed on aqueous solutions of dilute (10-3 M) isopolyoxomolybdate systems. There is direct evidence that the evaporation process in the ESMS technique involves significant chemical effects, resulting in the detection of many new anions and cations. For ammonium polyoxomolybdate systems, negative-ion ESMS yields ions of the form [HMomO3m + 1]-, [MomO3m + 1]2-, [MomO3m + 2]4- as well as [Mo7O24]6-, whereas for alkali metal polyoxomolybdate systems ions of the form [MomO3m + 1A]- and [MomO4mA2m-2]2- (where A = Li+, Na+ or K+) were observed. In positive-ion mode two series of polyoxomolybdate cations, namely [MomO4mA2m + 1]+ and [MomO4mA2m + 2]2+ could be assigned. Aggregates of both the [HMomO3m + 1]- and [MomO3m+ 1]2- series in the ammonium polyoxomolybdate system can be classified in terms of open-chained structures of tetrahedra that are corner shared, whereas the highly charged anions [MomO3m + 2]4- and [MomO3m + 3]6- are consistent with closed-packed structures. For the alkali metal polyoxomolybdate anion and cation systems the spectra are consistent with open-chained structures of octahedral units that are edge shared, with a terminating tetrahedral unit. Linear correlations suggest that the assembly of these aggregates occurs via an addition polymerization mechanism. This model, consistent with the ESMS data, may identify the additive moieties (MoO3, MoO22+ and Mo2O8A4) required for aggregation of polyoxomolybdate species in aqueous solution.
- Walanda, Daud K.,Burns, Robert C.,Lawrance, Geoffrey A.,Von Nagy-Felsobuki, Ellak I.
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p. 311 - 321
(2007/10/03)
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- Phase Relations in Li2MoO4-M2MoO4-Zr(MoO 4)2 (M = K or Rb) Systems
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The interaction in the subsolidus range (450-500°C) of ternary salt systems is studied using differential thermal and X-ray powder diffraction analyses. Three compounds are formed in the Li2MoO4-Rb2MoO4-Zr(MoO 4)2 system at molar component ratios of 1 : 1 : 2 (S1), 1 : 3 : 4 (S2), and 3 : 3 : 2 (S3). In contrast to the lithium-rubidium system, the Li2MoO4-K2MoO4-Zr(MoO 4)2 system forms no compounds.
- Bazarova,Gavrilova,Nimaeva
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p. 831 - 834
(2008/10/08)
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- Phase Formation in the Li2MoO4-Rb2MoO4-Ln2(MoO4)3 Systems and the Properties of LiRbLn2(MoO4)4
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Phase equilibria in the subsolidus region of the Li2MoO4-Rb2MoO4-Ln2(MoO4)4 (Ln=Nd or Er) ternary salt systems are studied. The formation of thetriple molybdate LiRbNd2(MoO)4 in the LiNd(MoO4)2-RbNd(MoO4)2 section i s confirmed. The phase diagram of this section is constructed. Similar compounds are prepared for Ln = La - Eu. Their monoclinic unit cell parameters are determined. The luminescent properties of LiRbLa2(MoO4)4 dopedwith Nd(3+) are studied.
- Basovich, O. M.,Khaikina, E. G.,Vasil'ev, E. V.,Frolov, A. M.
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p. 1966 - 1970
(2008/10/08)
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- Colloidal lithium centres in Li2MoO4 and Li2WO4
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Irradiation of polycrystalline Li2MoO4 or Li2WO4 with thermal neutrons in the range 1016-1019 N cm-2 produces centres of colloidal lithium detectable by ESR with g = 2.0035(3), ΔH = 2.8 Oe and g = 2.003(1), ΔH = 1.7 Oe respectively at a flux of 7.2 x 1018 N cm-2.The temperature dependence of the radiospectroscopic parameters of Licol was determined.It was shown that thermal treatment of the irradiated samples in the range 280-570 deg C was effective in aggregating the colloidal centres.The size of the colloidal particles and its temperature dependence were determined.Attention is called to the anomalously high stability of the Licol centres (the disappearance temperature and melting point are approximately the same) in the polycrystalline samples.On irradiating single crystals on the reactor Licol centres are not observed, but it was shown that at low temperatures (77 K) irradiation with accelerated electrons (5 MeV, dose about 105 Gy) produces colloidal lithium with g = 2.0026(3), ΔH = 1 Oe.The experimental results are interpreted in terms of the part played by the surface and by the radiation-chemical processes occuring in the oxyanions.
- Kurilenko, L. N.,Saunin, E. I.,Gromov, V. V.
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p. 815 - 818
(2007/10/02)
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- Radiation-induced Defects in the Lithium Salts of Normal Oxy-acids of the VI B Subgroup Elements
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Radiation-induced defects in the compounds Li2EO4 (where E= W, Mo, Cr), which have the phenacite structure, have been studied by ESR and thermoluminescence methods.In the case of polycrystalline Li2WO4 (hexagonal modification) treatment with γ quanta produces a signal with triaxial anisotropy (g1= 1.997, g2= 2.007, g3= 2.023) which disappears completely at 570 K and can be assigned to preferential localisation of a hole on the oxygen of the octahedral mononuclear groups found in impurity cubic phases, i.e. to defects of the WO65- type.The main impurity is Li2WO4 in the cubic modification.The thermal stability of the WO65- defects is much higher than that of the intrinsic tetrahedral hole centres. Mo as an impurity does not contribute significantly to the stabilization of the high-temperature hole centres in Li2WO4 and at low temperatures it affects the localisation conditions of both electrons and holes.The radiolysis of Li2MoO4 and Li2CrO4 is analogous to that of Li2WO4, but the stabilisation conditions of the resulting defects are different.The thermal stability of hole paramagnetic centres (HPC) of the EO65- type is correlated with the ΔH2980 value (the heat of formation of the compound), and the energy characteristics of the electron PMC (EO43- type) varies with the ionisation potential of the E5+ ions.
- Kurilenko, L. N.,Saunin, E. I.,Gromov, V. V.
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p. 666 - 668
(2007/10/02)
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