13568-40-6Relevant articles and documents
Electrical transport in the system Li2SO4-mLi2MoO4-2mLi3VO4
Lal,Gaur,Pathak
, p. 3683 - 3687 (1990)
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.
Thermochemistry of lithium chromate Li2CrO4(cr) and lithium molybdate Li2MoO4(cr)
Shukla, N.K.,Prasad, R.,Roy, K.N.,Sood, D.D.
, p. 897 - 903 (1992)
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).
Temperature induced phase transformations on the Li2MoO4 system studied by Raman spectroscopy
Saraiva,Paraguassu,Freire,Ramiro de Castro,de Sousa,Mendes Filho
, p. 119 - 124 (2017)
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.
Electrochemical behavior of submicron Li2MoO3 as anodes in lithium-ion batteries
Li, Dan,He, Hongyan,Wu, Ximin,Li, Mingqi
, p. 759 - 765 (2016)
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.
Electronic and ionic conduction in some simple lithium salts
Lal, H. B.,Gaur, Kanchan,Pathak, A. J.
, (1989)
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.
Synthesis and luminescence properties of a Li3BaCaY3(MoO4)8:Er3+ phosphor with a layered scheelite-like structure
Kozhevnikova
, (2017)
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
Raman and Density Functional Theory Studies of Li2Mo4O13 Structures in Crystalline and Molten States
Wan, Songming,Zhang, Bo,Yao, Yanan,Zheng, Guimei,Zhang, Shujie,You, Jinglin
, p. 14129 - 14134 (2017)
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.
Spontaneous formation of crystalline lithium molybdate from solid reagents at room temperature
Yip, Thomas W. S.,Cussen, Edmund J.,Wilson, Claire
, p. 411 - 417 (2010)
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.
Synthesis and structure of a 3D porous network containing aromatic 1D chains of Li6 rings: Experimental and computational studies
Deb, Dibakar,Giri, Santanab,Chattaraj, Pratim K.,Bhattacharjee, Manish
, p. 10871 - 10877 (2010)
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.
Thermodynamic Properties of M2EO4, M2MoxO3x + 1 and Double Chromates (M = Li, Na, K, Rb, Cs; E = Cr, Mo, W)
Suponitskiy, Yu. L.,Zolotova,Dyunin,Liashenko
, p. 397 - 400 (2018)
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.
Optical and AC conductivity studies on Li2-xRbx MoO4 (xu202f=u202f0, 0.5, 1) compounds
Ben Nasr,Mahmoud,Boschini,Ben Rhaiem
, p. 522 - 532 (2019)
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).
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
Zolotova,Solodovnikova,Ayupov,Solodovnikov
, p. 1216 - 1221 (2011)
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
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
Basovich,Khaikina,Solodovnikov,Tsyrenova
, p. 1580 - 1588 (2005)
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).
Buechler, A.,Stauffer, J. L.,Klemperer, W.,Wharton, L.
, p. 2299 - 2303 (1963)
