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1.
Abril Carolina Castro Martha Audiffred Jose M. Mercero Jesus M. Ugalde Miguel A. Méndez-Rojas Gabriel Merino 《Chemical physics letters》2012
The structures and bonding of the CE42?clusters (E = Al, Ga, In, Tl) have been theoretically studied via B3LYP/def2-TZVP computations. Total energies were recalculated at the CCSD(T)/def2-TZVPP//B3LYP/def2-TZVP level in order to corroborate the energy differences. Our computations show that all the CE42?and CE4Li?clusters (E = Al, Ga, In,Tl) have a planar tetracoordinate carbon structure. Interestingly, while the most stable form of CAl4Li? and CGa4Li? is planar with coordination of Li+ to an edge of the CE42? fragment, for CIn4Li? and CTl4Li? the pyramidal structures with C4v symmetry are the lowest-energy structures. 相似文献
2.
Crystal Structures of MgCrO4-type Li2VCl4 and Spinel-type Li2MgCl4 and Li2CdCl4 The crystal structures of the ternary lithium chlorides Li2MCl4 (M = Mg, V, Cd) have been determined firstly by X-ray single-crystal experiments. Li2MgCl4 and Li2CdCl4 crystallize in an inverse spinel structure (space group Fd3 m, Z = 8, a = 1 040.1(2) and 1 062.06(9) pm, structural parameters u = 0.25699(2) and 0.2550(1), R = 1.7 and 3.7% for 218 and 211 unique reflections). The Li? Cl distances of the tetrahedrally coordinated Li+ ions are significantly greater than calculated with Shannon's crystal radii ( > 238 ± 1 instead of 233 pm). Contrary to the results of X-ray powder data reported in the literature, Li2VCl4 crystallizes in the distorted spinel structure of MgCr2O4 type (space group F4 3m, Z = 8, a = 1 037.49(2) pm, R = 5.9% for 217 unique reflections). The decrease of the site symmetry of the octahedrally coordinated ions (V2+, Li+) from 3 m to 3m resulting in contracted and widened tetrahedral M4 entities of the spinel structure is obviously caused by V? V metal—metal bonds (shortest V? V distance 366.2(7) pm). 相似文献
3.
G. D. Ilyushin 《Russian Journal of Inorganic Chemistry》2018,63(14):1796-1811
The structural chemistry of lithium intermetallic compounds that are formed in Li–М binary systems where М = Ca, Sr, Ba, Mg, Zn, Cd, and Hg is surveyed. It is for the first time that the crystal structures of intermetallic compounds are classified in terms of polyhedral precursor metal clusters (in the program package ToposPro). The precursor metal clusters of crystal structures are identified using the algorithms of partitioning structural graphs into cluster structures and via the design of the basal 3D network of the structure in the form of a graph whose nodes correspond to the positions of the centers of precursor clusters. Tetrahedral precursor metal clusters M4 are identified for the crystal structures LiZn3-oC4, LiMg3-hP2, LiCd3-hP2, LiHg3-hP8, (LiMg3)(Li2Mg2)-tI16, Li2Zn2-cF16, Li2Cd2-cF16, Li2Hg2-cP2, Li3Cd-cF4, and Li3Hg-cF16; tetrahedral metal clusters M4 are found for the framework structures with spacer atoms Sr(Li2Sr2)-tP20, Ca2(Li4)-cF24, and Ca2(Li4)-cP12; tetrahedral metal clusters M4 and rings M6, for framework structures Ba3Li2(Li10)-hP30 and Ba3Li2(Li4In6)-hP30; icosahedral metal clusters M13 for the framework structure Li(Zn13)-cF112; bilayer tetrahedral metal clusters 0@М4@M22 for the framework structure Li23Sr6-cF116; and deltahedra М17 and deltahedra М30, for framework structures Sr4Li14 [Sr(Sr4Li12)] [(Sr2 (Sr8Li18)]-tI252 and Ba4Li14 [Ba(Ba4Li12)][(Ba2 (Ba8Li18)]-tI252. The scenario of crystal structure self-assembly from precursor metal clusters S30 in intermetallic compounds is reconstituted as: primary chain S31→ microlayer S32→ microframework S33. 相似文献
4.
Contributions to the Chemistry of Phosphorus. 143. Li4P26 and Na4P26, the First Salts with Hexacosaphosphid(4?) Ions The hexacosaphosphides Li4P26 ( 1 ) and Na4P26 ( 2 ) are formed besides other polyphosphides in the reaction of white phosphorus with lithium dihydrogenphosphide or sodium. 1 also results from the decomposition of Li2HP7 in tetrahydrofuran at room temperature and can be obtained pure as a crystalline solvent adduct Li4P26 · 16 THF. According to 2D?31P-NMR spectroscopic investigations the P264? ion is a conjucto-phosphane of two P7(5)?-and two P9(3)?-unit groups with structures analogous to norbornane and deltacyclane, respectively. 相似文献
5.
Andreas Bohnsack Frauke Stenzel Armin Zajonc Gert Balzer Mathias S. Wickleder Gerd Meyer 《无机化学与普通化学杂志》1997,623(7):1067-1073
Ternary Halides of the A3MX6 Type. VI. Ternary Chlorides of the Rare-Earth Elements with Lithium, Li3MCl6 (M ? Tb? Lu, Y, Sc): Synthesis, Crystal Structures, and Ionic Motion Single crystal X-ray studies on the ternary chlorides Li3ErCl6, Li3YbCl6 and Li3ScCl6 show that they crystallize in three different structure types. Li3ErCl6 (trigonal, P3 ml, Z = 3, a = 1117.7(2); c = 603.6(2) pm; the chlorides with M ? Tb? Tm, Y are isotypic) and Li3YbCl6 (orthorhombic, Pnma, Z = 4, a = 1286.6(1); b = 1113.2(1); c = 602.95(8) pm; Li3LuCl6 is isotypic) have very similar structures that may be derived from hexagonal closest packings of chloride ions with the cations occupying octahedral holes in part statistically. Li3ScCl6 (monoclinic, C2/m, Z = 2, a = 639.8(1); b = 1104.0(2); c = 639,1(1) pm; β = 109.89(1)°) crystallizes isotypic with Na3GdI6 and Li3ErBr6, structures that may be derived from a cubic closes packings of anions. The ionic movement in Li3YCl6 and Li3YbCl6 has been investigated by impedance and 7Li-NMR spectroscopy. 相似文献
6.
The crystal chemistry of Li3PO4, Li3VO4 and Li3AsO4 are compared. All three have an isostructural low phase, designated βII, and an isostructural high phase, γII, but in Li3VO4 and Li3AsO4 the high-low transformation proceeds reversibly through one or more transitional phases some of which can be quenched to ambient. The crystal chemistry of derivative Li3PO4 phases, including Li2MgSiO4, Li2ZnSiO4, Li2CoSiO4, Li2MgGeO4 and Li2ZnGeO4 is compared and the occurrence of high, low, and of distorted high and low phases is correlated with the temperature of preparation and rate of cooling. The derivative Li3PO4 phases show extensive or complete mutual solubility not only with each other, but with Li3PO4, with M2XO4 compounds (M = Zn2+, Mg2+; X = Ge4+, Si4+) and also with Li4XO4 compounds (X = Ge4+, Si4+). The sequence of phase transformations encountered on heating or cooling is quite sensitive to the stoichiometry of the derivative phases. 相似文献
7.
A. Belous G. Kolbasov L. Kovalenko E. Boldyrev S. Kobylianska B. Liniova 《Journal of Solid State Electrochemistry》2018,22(8):2315-2320
The Li0.33Lia0.56TiO3 and Li1.3Ti1.7Al0.3(PO4)3 ceramics with the structures of defect-perovskite and NASICON structures with conductivity of 1–6?×?10?6 S/cm at the room temperature are obtained. Ceramic electrolytes were developed for a solid-state battery EMF of 4.1 V and high discharge stability in time. Discharge characteristics of solid-state batteries are studied in a laboratory cell. 相似文献
8.
A mixed vanadate In0.6Li1.2VO4 has been synthesized from an equimolecular mixture of InVO4 and Li3VO4. The exact chemical formula has been determined by a crystal structure refinement. Crystallographic data are: a = 5.763(1), b = 8.742(2), c = 6.385(3)Å, Z = 4, dcalc = 3.97 g cm?3. Seven hundred twenty-six reflections have been used for structure determination and refinement, to a final value R = 0.019, after absorption and extinction corrections. InO6 octahedra and VO4 tetrahedra are linked together in the same three-dimensional network that exists in InVO4. Nevertheless, a partial substitution of In3+ by Li+ and an insertion of Li+ in tetrahedral interstices occur. Vacancies exist, either in the octahedral and tetrahedral positions, In0.6Li(6)0.3□(6)0.1Li(4)0.9□(4)0.1VO4, or solely in the tetrahedral positions, In0.6Li(6)0.4Li(4)0.8□(4)0.2VO4. 相似文献
9.
R. A. Bartlett X. Feng M. M. Olmstead P. P. Power 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):245-248
Abstract The structures of several solvated lithium diorganophosphides are described. These may take a variety of structures including chain-like polymers with alternating Li+ and PR2 ? groups, dimeric species with PR2 ? groups bridging two Li+ ions or mononuclear species having terminal ?PR2 groups which have pyramidal geometries at phosphorus. The Li+ ions in all structures are solvated by either THF or Et2O bases. Separation of the Li+ can be effected using 12-crown-4 to coordinate Li+ as [Li(12-crown-4)2]+ affording free [PR2]? counterions. An extension of these techniques has led to the synthesis of the first compounds which have B-P double bonds. These are the compounds [Li(Et2O)2PRBMes2] and [Li(12-crown-4)2][PRBMes2](R=Ph, C6H11,Mes) which have B-P bond lengths of 1.82 – 1.83Å. 相似文献
10.
Two New Silicate-Chlorides with Divalent Europium: LiEu3[SiO4]Cl3 and Li7Eu8[SiO4]4Cl7 LiEu3[SiO4]Cl3 was prepared by reaction of LiCl with Eu2SiO4 and Li7Eu8[SiO4]4Cl7 from Li with Eu2O3, SiO2 and LiCl. The crystal structures of LiEu3[SiO4]Cl3 (Pmna, a = 946.95(13); b = 699.52(8); c = 1 368.0(2) pm; Z = 4; R1 = 0.0325, R2w = 0.0642) and Li7Eu8[SiO4]4Cl7 (P21/c; a = 851.85(5); b = 948.62(7); c = 1 679.0(2) pm; β = 96.221(8)°; Z = 2; R1 = 0.0352, R2w = 0.0744) were determined from four-circle diffractometer data. LiEu3[SiO4]Cl3 contains [Li(SiO4)2] units and LiCl6 octahedra while in Li7Eu8[SiO4]4Cl7 larger ?lithosilicate”? groups are found. In both structures, the Eu2+ ions are coordinated mostly eightfold by O2? and Cl? ligands. 相似文献
11.
Single crystals of LiCr(MoO4)2, Li3Cr(MoO4)3 and Li1.8Cr1.2(MoO4)3 were grown by a flux method during the phase study of the Li2MoO4-Cr2(MoO4)3 system at 1023 K. LiCr(MoO4)2 and Li3Cr(MoO4)3 single phases were synthesized by solid-state reactions. Li3Cr(MoO4)3 adopts the same structure type as Li3In(MoO4)3 despite the difference in ionic radii of Cr3+ and In3+ for octahedral coordination. Li3Cr(MoO4)3 is paramagnetic down to 7 K and shows a weak ferromagnetic component below this temperature. LiCr(MoO4)2 is isostructural with LiAl(MoO4)2 and orders antiferromagnetically below 20 K. The magnetic structure of LiCr(MoO4)2 was determined from low-temperature neutron diffraction and is based on the propagation vektor . The ordered magnetic moments were refined to 2.3(1) μB per Cr-ion with an easy axis close to the [1 1 1¯] direction. A magnetic moment of 4.37(3) μB per Cr-ion was calculated from the Curie constant for the paramagnetic region.The crystal structures of the hitherto unknown Li1.8Cr1.2(MoO4)3 and LiCr(MoO4)2 are compared and reveal a high degree of similarity: In both structures MoO4-tetrahedra are isolated from each other and connected with CrO6 and LiO5 via corners. In both modifications there are Cr2O10 fragments of edge-sharing CrO6-octahedra. 相似文献
12.
Masahiro Murayama Ryoji Kanno Michihiko IrieShinya Ito Takayuki HataNoriyuki Sonoyama Yoji Kawamoto 《Journal of solid state chemistry》2002,168(1):140-148
The new lithium ionic conductors, thio-LISICON (LIthium SuperIonic CONductor), were found in the ternary Li2S-SiS2-Al2S3 and Li2S-SiS2-P2S5 systems. Their structures of new materials, Li4+xSi1−xAlxS4 and Li4−xSi1−xPxS4 were determined by X-ray Rietveld analysis, and the electric and electrochemical properties were studied by electronic conductivity, ac conductivity and cyclic voltammogram measurements. The structure of the host material, Li4SiS4 is related to the γ-Li3PO4-type structure, and when the Li+ interstitials or Li+ vacancies were created by the partial substitutions of Al3+ or P5+ for Si4+, large increases in conductivity occur. The solid solution member x=0.6 in Li4−xSi1−xPxS4 showed high conductivity of 6.4×10-4 S cm−1 at 27°C with negligible electronic conductivity. The new solid solution, Li4−xSi1−xPxS4, also has high electrochemical stability up to ∼5 V vs Li at room temperature. All-solid-state lithium cells were investigated using the Li3.4Si0.4P0.6S4 electrolyte, LiCoO2 cathode and In anode. 相似文献
13.
Robust Inclusion Complexes of Crown Ether Fused Tetrathiafulvalenes with Li+@C60 to Afford Efficient Photodriven Charge Separation
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Dr. Mustafa Supur Yuki Kawashima Dr. Karina R. Larsen Dr. Kei Ohkubo Prof. Jan O. Jeppesen Prof. Shunichi Fukuzumi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(43):13976-13983
Inclusion complexes of benzo‐ and dithiabenzo‐crown ether functionalized monopyrrolotetrathiafulvalene (MPTTF) molecules were formed with Li+@C60 ( 1? Li+@C60 and 2? Li+@C60). The strong complexation has been quantified by high binding constants that exceed 106 M ?1 obtained by UV/Vis titrations in benzonitrile (PhCN) at room temperature. On the basis of DFT studies at the B3LYP/6‐311G(d,p) level, the orbital interactions between the crown ether moieties and the π surface of the fullerene together with the endohedral Li+ have a crucial role in robust complex formation. Interestingly, complexation of Li+@C60 with crown ethers accelerates the intersystem crossing upon photoexcitation of the complex, thereby yielding 3(Li+@C60)*, when no charge separation by means of 1Li+@C60* occurs. Photoinduced charge separation by means of 3Li+@C60* with lifetimes of 135 and 120 μs for 1? Li+@C60 and 2? Li+@C60, respectively, and quantum yields of 0.82 in PhCN have been observed by utilizing time‐resolved transient absorption spectroscopy and then confirmed by electron paramagnetic resonance measurements at 4 K. The difference in crown ether structures affects the binding constant and the rates of photoinduced electron‐transfer events in the corresponding complex. 相似文献
14.
Wanderson S. Jesus Jorge M. C. Marques Frederico V. Prudente Francisco B. Pereira 《International journal of quantum chemistry》2019,119(13):e25860
An evolutionary algorithm was used to search for the low-energy structures of Li+Arn and Li+Krn (n = 1 − 14). Two functions were used to describe the interaction potential at the CCSD(T)/aug-cc-pVQZ level of theory: one is based on a sum of all pair potentials, whereas the other includes three-body interactions. In general, the global minimum structures are similar for both Li+Arn and Li+Krn. Modifications in the octahedral structure of the first solvation shell lead to a high-energy penalty. Conversely, the second solvation shell shows a panoply of minima with similar energies that are likely to be interconverted. Post-optimization at the MP2 level confirmed that, for n = 2 and 3, one has to include three-body terms in the potential to reproduce the low-energy structures. Additionally, MP2 calculations indicate that energy reorder of the global minimum structure observed for Li+Kr8 is related to the Kr3 Axilrod-Teller-Muto term included in the potential. 相似文献
15.
The compositional variation of the chemical diffusion coefficient in the six intermediate phases LiSn, Li7Sn3, Li5Sn2, Li13Sn5, Li7Sn2, and Li22Sn5 of the lithium-tin system at 415°C has been measured. Among these intermediate phases, the phase Li13Sn5 has the highest chemical diffusion coefficient, varying with composition from 5.01 × 10?5 to 7.59 × 10?4 cm2/sec at that temperature. Combining this information with coulometric titration curves (emf versus composition), the self-diffusion coefficient of lithium has also been determined in the various intermetallic phases as a function of composition under the assumption that the tin atoms do not move appreciably compared with the lithium atoms. The lithium self-diffusion coefficient in the phase LiSn is lower than those in the more lithium-rich phases by one order of magnitude. This result is discussed in terms of the difference between the crystal structures of LiSn and the other lithium-rich phases in the lithium-tin system. 相似文献
16.
Maryel Contreras Dr. Edison Osorio Franklin Ferraro Gustavo Puga Prof. Kelling J. Donald Jason G. Harrison Prof. Gabriel Merino Prof. William Tiznado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(7):2305-2310
The most stable forms of E5Li7+ (E=Ge, Sn, and Pb) have been explored by means of a stochastic search of their potential‐energy surfaces by using the gradient embedded genetic algorithm (GEGA). The preferred isomer of the Ge5Li7+ ion is a slightly distorted analogue of the D5h three‐dimensional seven‐pointed starlike structure adopted by the lighter C5Li7+ and Si5Li7+ clusters. In contrast, the preferred structures for Sn5Li7+ and Pb5Li7+ are quite different. By starting from the starlike arrangement, corresponding lowest‐energy structures are generated by migration of one of the E atoms out of the plane with the a corresponding rearrangement of the Li atoms. To understand these structural preferences, we propose a new energy decomposition analysis based on isomerizations (isomerization energy decomposition analysis (IEDA)), which enable us to extract energetic information from isomerization between structures, mainly from highly charged fragments. 相似文献
17.
Substitution of Lithium for Magnesium,Zinc, and Aluminum in Li15Si4: Crystal Structures,Thermodynamic Properties,as well as 6Li and 7Li NMR Spectroscopy of Li15Si4 and Li15−xMxSi4 (M=Mg,Zn, and Al)
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Dr. Volodymyr Baran Prof. Dr. Leo van Wüllen Prof. Dr. Thomas F. Fässler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6598-6609
An investigation into the substitution effects in Li15Si4, which is discussed as metastable phase that forms during electrochemical charging and discharging cycles in silicon anode materials, is presented. The novel partial substitution of lithium by magnesium and zinc is reported and the results are compared to those obtained for aluminum substitution. The new lithium silicides Li14MgSi4 ( 1 ) and Li14.05Zn0.95Si4 ( 2 ) were synthesized by high‐temperature reactions and their crystal structures were determined from single‐crystal data. The magnetic properties and thermodynamic stabilities were investigated and compared with those of Li14.25Al0.75Si4 ( 3 ). The substitution of a small amount of Li in metastable Li15Si4 for more electron‐rich metals, such as Mg, Zn, or Al, leads to a vast increase in the thermodynamic stability of the resulting ternary compounds. The 6,7Li NMR chemical shift and spin relaxation time T1‐NMR spectroscopy behavior at low temperatures indicate an increasing contribution of the conduction electrons to these NMR spectroscopy parameters in the series for 1 – 3 . However, the increasing thermal stability of the new ternary phases is accompanied by a decrease in Li diffusivity, with 2 exhibiting the lowest activation energy for Li mobility with values of 56, 60, and 62 kJ mol?1 for 2 , Li14.25Al0.75Si14, and 1 , respectively. The influence of the metastable property of Li15Si4 on NMR spectroscopy experiments is highlighted. 相似文献
18.
《Journal of solid state chemistry》1987,67(2):316-323
The crystal structures of the lithium-rich and lithium-deficient spinel phases Li2[Mn2]O4 and Li0.2[Mn2]O4 have been determined by neutron-diffraction techniques. Structure refinements confirm earlier reports that the [Mn2]O4 framework of the Li[Mn2]O4 spinel remains intact during both lithium insertion and extraction, but demonstrate unequivocally that in Li2[Mn2]O4 the Li+ ions reside in face-shared tetrahedra and octahedra of the cubic-close-packed oxygen-anion array; in Li0.2[Mn2]O4 the Li+ ions are located randomly on only the tetrahedral sites of the spinel structure. 相似文献
19.
The galvanostatic intermittent titration technique (GITT) has been used to electrochemically determine the chemical and component diffusion coefficients, the electrical and general lithium mobilities, the partial lithium ionic conductivity, the parabolic tarnishing rate constant, and the thermodynamic enhancement factor in “Li3Sb” and “Li3Bi” as a function of stoichiometry in the temperature range from 360 to 600°C. LiCl, KCl eutectic mixtures were used as molten salt electrolytes and Al, “LiAl” two-phase mixtures as solid reference and counterelectrodes. The stoichiometric range of the antimony compound is rather small, 7 × 10?3 at 360°C, whereas the bismuth compound has a range of 0.22 (380°C), mostly on the lithium deficit side of the ideal composition. The thermodynamic enhancement factor in “Li3Sb” depends strongly on the stoichiometry, and has a peak value of nearly 70 000; for “Li3Bi” it rises more smoothly to a maximum of 360. The chemical diffusion coefficient for “Li3Sb” is 2 × 10?5 cm2 sec?1 at negative deviations from the ideal stoichiometry and increases by about an order of magnitude in the presence of excess lithium at 360°C. The corresponding value for “Li3Bi” is 10?4 cm2 sec?1 with high lithium deficit, and increases markedly when approaching ideal stoichiometry. The activation energies are small, 0.1–0.3 eV, depending on the stoichiometry, in both phases. The mobility of lithium in “Li3Bi” is about 500 times greater than in “Li3Sb” with a lithium deficit. The ionic conductivity in “Li3Sb” increases from about 10?4 Ω?1 cm?1 in the vacancy transport region to about 2 × 10?3 where transport is probably by interstial motion at 360°C. For “Li3Bi” a practically constant value of nearly 10?1 Ω?1 cm?1 is found at 380°C. The parabolic tarnishing rate constant shows a sharp increase at higher lithium activities in “Li3Sb” whereas in “Li3Bi” it has a roughly linear dependence upon the logarithm of the lithium activity. The tarnishing process is about 2 orders of magnitude slower for “Li3Sb” than for “Li3Bi.” Because of the fast ionic transport in these mixed conducting materials, “Li3Sb” and “Li3Bi” may be called “fast electrodes.” 相似文献
20.
Mechanism of Dissolution of a Lithium Salt in an Electrolytic Solvent in a Lithium Ion Secondary Battery: A Direct Ab Initio Molecular Dynamics (AIMD) Study
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Dr. Hiroto Tachikawa 《Chemphyschem》2014,15(8):1604-1610
The mechanism of dissolution of the Li+ ion in an electrolytic solvent is investigated by the direct ab initio molecular dynamics (AIMD) method. Lithium fluoroborate (Li+BF4?) and ethylene carbonate (EC) are examined as the origin of the Li+ ion and the solvent molecule, respectively. This salt is widely utilized as the electrolyte in the lithium ion secondary battery. The binding of EC to the Li+ moiety of the Li+BF4? salt is exothermic, and the binding energies at the CAM–B3LYP/6‐311++G(d,p) level for n=1, 2, 3, and 4, where n is the number of EC molecules binding to the Li+ ion, (EC)n(Li+BF4?), are calculated to be 91.5, 89.8, 87.2, and 84.0 kcal mol?1 (per EC molecule), respectively. The intermolecular distances between Li+ and the F atom of BF4? are elongated: 1.773 Å (n=0), 1.820 Å (n=1), 1.974 Å (n=2), 1.942 Å (n=3), and 4.156 Å (n=4). The atomic bond populations between Li+ and the F atom for n=0, 1, 2, 3, and 4 are 0.202, 0.186, 0.150, 0.038, and 0.0, respectively. These results indicate that the interaction of Li+ with BF4? becomes weaker as the number of EC molecules is increased. The direct AIMD calculation for n=4 shows that EC reacts spontaneously with (EC)3(Li+BF4?) and the Li+ ion is stripped from the salt. The following substitution reaction takes place: EC+(EC)3(Li+BF4?)→(EC)4Li+?(BF4?). The reaction mechanism is discussed on the basis of the theoretical results. 相似文献