Structural Phase Transition in Li2C2

Ruschewitz, Uwe; Pöttgen, Rainer

doi:10.1002/(sici)1521-3749(199910)625:10<1599::aid-zaac1599>3.0.co;2-j

Cited by 85 publications

(53 citation statements)

References 12 publications

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“…Between the rods the lithium atoms are coordinated to three C 2 pairs in a side-on fashion. Similar to binary Li 2 C 2 [91], also these highly ionic acetylides are extremely moisture sensitive.…”

Section: Lithium-transition Metal-acetylidesmentioning

confidence: 99%

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Pöttgen¹,

Dinges

Eckert

et al. 2010

Zeitschrift Für Physikalische Chemie

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Lithium / Tetrelides / Ionic Mobility / Crystal ChemistryLithium-transition metal (T)-tetrelides (tetr. = C, Si, Ge, Sn, Pb) are an interesting class of materials with greatly differing crystal structures. The transition metal and tetrel atoms build up covalently bonded networks which leave cavities or channels for the lithium atoms. Depending on the bonding of the lithium atoms to the polyanionic network one observes mobility of the lithium atoms. The crystal chemistry, chemical bonding, 7 Li solid state NMR, and the electrochemical behavior of the tetrelides are reviewed herein.

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Section: Lithium-transition Metal-acetylidesmentioning

confidence: 99%

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Pöttgen¹,

Dinges

Eckert

et al. 2010

Zeitschrift Für Physikalische Chemie

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“…A series of lithium carbon binary compounds (including Li 6 C[ [25][26][27], Li 5 C [25,26], Li 4 C[25,26,[28][29][30][31][32][33], Li 3 C[28, [32][33][34][35][36], Li 8 C 3 [33], Li 2 C[31, [33][34][35][36], Li 4 C 3 [29,31,[33][34][35][37][38][39][40], Li 2 C 2 [29,31,33,36,[41][42][43], Li 4 C 5 [33,44], LiC 2 [45], LiC 3 [45], LiC 6 [43,46,47], LiC 10 [48], and LiC 12 [43,46,47], etc.) have been reported theoretically...…”

Section: Introductionmentioning

confidence: 99%

“…Most of those previous studies focused on the molecular structure and the stability of molecular clusters. Of these reported compounds, only Li 2 C 2 [33,41,[49][50][51][52][53][54][55] and some graphite intercalation compounds (LiC 6 and LiC 12 , etc.) [47,53,[56][57][58][59][60] have been investigated experimentally in their crystal structures.…”

Section: Introductionmentioning

confidence: 99%

Structural diversity in lithium carbides

2015

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The lithium-carbon binary system possesses a broad range of chemical compounds, which exhibit fascinating chemical bonding characteristics that give rise diverse and technologically important properties. While lithium carbides with various compositions have been studied or suggested previously, the crystal structures of these compounds are far from well understood. In this work we present the first comprehensive survey of all ground state (GS) structures of lithium carbides over a broad range of thermodynamic conditions, using ab initio density functional theory (DFT) crystal structure searching methods. Thorough searches were performed for 29 stoichiometries ranging from Li12C to LiC12 at 0 GPa as well as 40 GPa. Based on formation enthalpies from optimized van der Waals density functional calculations, three thermodynamically stable phases (Li4C3, Li2C2 and LiC12) were identified at 0 GPa, and seven thermodynamically stable phases (Li8C, Li6C, Li4C, Li8C3, Li2C, Li3C4, and Li2C3) were predicted at 40 GPa. A rich diversity of carbon bonding, including monomers, dimers, trimers, nanoribbons, sheets and frameworks, was found within these structures, and the dimensionality of carbon connectivity existing within each phase was observed to increase with increasing carbon concentration. Of particular interest, we find that the wellknown composition LiC6 is actually a metastable one. We also find a unique coexistence of carbon monomers and dimers within the predicted thermodynamically stable phase Li8C3, and different widths of carbon nanoribbons coexist in a metastable phase of Li2C2 (Imm2). Interesting mixed sp 2 -sp 3 carbon frameworks are predicted in metastable phases with composition LiC6.

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“…The multielement cases are needed to understand the feature of antimetallization from a different perspective at the fundamental level. For this purpose, the compounds of C m Li n are considered to be good examples for the understanding of the nature of physics (12)(13)(14). Examining their high-pressure behavior and exploring the possible metallization and superconductivity in this system are the focus of this work.…”

mentioning

confidence: 99%

Crossover from metal to insulator in dense lithium-rich compound CLi ₄

Jin

Chen

Cui

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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At room environment, all materials can be classified as insulators or metals or in-between semiconductors, by judging whether they are capable of conducting the flow of electrons. One can expect an insulator to convert into a metal and to remain in this state upon further compression, i.e., pressure-induced metallization. Some exceptions were reported recently in elementary metals such as all of the alkali metals and heavy alkaline earth metals (Ca, Sr, and Ba).Here we show that a compound of CLi 4 becomes progressively less conductive and eventually insulating upon compression based on ab initio density-functional theory calculations. An unusual path with pressure is found for the phase transition from metal to semimetal, to semiconductor, and eventually to insulator. The Fermi surface filling parameter is used to describe such an antimetallization process.high pressure | antimetallization | lithium-rich compound S imilar to the same first group element, hydrogen, lithium with a single valence electron is a good conductor of heat and metal at ambient conditions. It can transform from a nearly freeelectron metallic solid to an insulating one, i.e., pressure-induced antimetallization (1-4). As a contrasting counterpart, lithium often provides a meaningful referential aspect for understanding hydrogen at high pressures (5). Hydrogen-rich materials of group-IV hydrides (6-10) are believed to be good candidates for the realization of metallization and even superconductivity at modest pressures much lower than that required for pure hydrogen due to "chemical precompression." Whether group-IV lithium compounds hold similar expected outstanding properties to those of their same group hydrides becomes an interesting topic.On the other hand, high-pressure studies delivered a completely unexpected antimetallization behavior for alkali metals such as Li (1, 3, 4) and Na (11). Charge transition from 2s to 2p of Li or Na itself was proposed to account for such a behavior. Being restricted to the pure elements in these cases, some underlying properties are covered. The multielement cases are needed to understand the feature of antimetallization from a different perspective at the fundamental level. For this purpose, the compounds of C m Li n are considered to be good examples for the understanding of the nature of physics (12)(13)(14). Examining their high-pressure behavior and exploring the possible metallization and superconductivity in this system are the focus of this work.We have explored the crystal structures of lithium-rich compounds CLi n in a wide pressure range from ambient pressure to 300 GPa. Fig. 1 shows the enthalpy-pressure curves of CLi 4 and the possible decomposition to the elements and compounds. The other possible lithium-rich carbides CLi n (n = 2 ∼ 6) and their stabilities can be found in SI Appendix, Fig. S1. Obviously, the compound of CLi 4 is stable at least above 3 GPa and below 300 GPa. Before about 3 GPa, CLi 4 is unstable and decomposes into a C 2 Li 2 and Li mixture. After about 3 GPa, CLi 4 com...

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Structural Phase Transition in Li2C2

Cited by 85 publications

References 12 publications

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Structural diversity in lithium carbides

Crossover from metal to insulator in dense lithium-rich compound CLi ₄

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Structural Phase Transition in Li2C2

Cited by 85 publications

References 12 publications

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Lithium-Transition Metal-Tetrelides – Structure and Lithium Mobility

Structural diversity in lithium carbides

Crossover from metal to insulator in dense lithium-rich compound CLi 4

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Crossover from metal to insulator in dense lithium-rich compound CLi ₄