Lithium Intercalation into β‐Rhombohedral Boron: LiB∼10 or Li30B309?

Vojteer, Natascha; Stauffer, Julia; Hillebrecht, Harald; Hofmann, Kathrin; Panda, Monalisa; Albert, Barbara

doi:10.1002/zaac.200900111

Cited by 22 publications

(28 citation statements)

References 31 publications

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“…[176] It is well known that boron carbides can have various compositions with a carbon content between 10 and 20 %. Uncertainties as to the precise determination of the carbon [165,175] content may be ascribed to their direct synthesis from the elements at high temperatures as well as to the chemical stability of the bonds and the elements involved. Investigations in to the stability range have found a maximum melting point at 2450 8C for a carbon content of about 18.5 %.…”

Section: General Observationsmentioning

confidence: 99%

“…[127] This formula is based on structural examinations performed on highly pure crystal powders and single crystals obtained by metal flux. The same phase was earlier called LiB 13 .…”

Section: General Observationsmentioning

confidence: 99%

“…[165,175] Lithium atoms partially occupied a 6h position above and below the CBC unit in the practically colorless Li 0.25 B 13 C 2 . The lithium incorporation was detected by means of EELS.…”

Section: General Observationsmentioning

confidence: 99%

“…[126] It was shown for LiB 10 that the lithium content and the boron atom arrangement depended on the reaction conditions. [127] Aluminum, copper, gallium, tin, and also mixtures of these metals (Cu/Mg, Al/Mg, Li/Sn, Li/Ga) have been found to be particularly suitable for the synthesis of borides [129][130][131] in metal melts (auxiliary metal-bath technique [128] ), but metals such as palladium have also occasionally been used. [132] Lower reaction temperatures may be used than in direct conversion, so that another area of the phase diagram becomes accessible.…”

Section: Synthesismentioning

confidence: 99%

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Boron: Elementary Challenge for Experimenters and Theoreticians

Albert¹,

Hillebrecht²

2009

Angew Chem Int Ed

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Many of the fundamental questions regarding the solid-state chemistry of boron are still unsolved, more than 200 years after its discovery. Recently, theoretical work on the existence and stability of known and new modifications of the element combined with high-pressure and high-temperature experiments have revealed new aspects. A lot has also happened over the last few years in the field of reactions between boron and main group elements. Binary compounds such as B(6)O, MgB(2), LiB(1-x), Na(3)B(20), and CaB(6) have caused much excitement, but the electron-precise, colorless boride carbides Li(2)B(12)C(2), LiB(13)C(2), and MgB(12)C(2) as well as the graphite analogue BeB(2)C(2) also deserve special attention. Physical properties such as hardness, superconductivity, neutron scattering length, and thermoelectricity have also made boron-rich compounds attractive to materials research and for applications. The greatest challenges to boron chemistry, however, are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation. Linked polyhedra are the dominating structural elements of the boron-rich compounds of the main group elements. In many cases, their structures can be derived from those that have been assigned to modifications of the element. Again, even these require a critical revision and discussion.

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Section: General Observationsmentioning

confidence: 99%

“…[127] This formula is based on structural examinations performed on highly pure crystal powders and single crystals obtained by metal flux. The same phase was earlier called LiB 13 .…”

Section: General Observationsmentioning

confidence: 99%

Section: General Observationsmentioning

confidence: 99%

Section: Synthesismentioning

confidence: 99%

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Boron: Elementary Challenge for Experimenters and Theoreticians

Albert¹,

Hillebrecht²

2009

Angew Chem Int Ed

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560

436

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“…[165,175] Im nahezu farblosen Li 0.25 B 13 C 2 besetzen Lithiumatome partiell eine 6h-Lage oberund unterhalb der CBC-Einheit. Der Nachweis des LithiumEinbaus erfolgte durch EELS.…”

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Bor – elementare Herausforderung für Experimentatoren und Theoretiker

Albert

Hillebrecht

2009

Angewandte Chemie

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Auch mehr als zweihundert Jahre nach der Entdeckung des Elementes Bor gibt es auf viele grundlegende Fragen in der Festkörperchemie von Bor noch keine eindeutigen Antworten. In jüngster Zeit zeigten theoretische Arbeiten zur Stabilität und Existenz bekannter und neuer Modifikationen des Elements in Verbindung mit Hochdruck‐ und Hochtemperaturexperimenten neue Aspekte. Auch auf dem Gebiet der Reaktionen von Bor mit Hauptgruppenelementen hat sich in den letzten Jahren viel getan. Aufsehen haben binäre Verbindungen wie B6O, MgB2, LiB1−x, Na3B20 oder CaB6 erregt, aber auch die elektronenpräzisen, farblosen Boridcarbide Li2B12C2, LiB13C2 und MgB12C2 sowie Graphit‐analoges BeB2C2 verdienen besonderes Augenmerk. Physikalische Eigenschaften wie Härte, Supraleitfähigkeit, Neutroneneinfangquerschnitt und Thermoelektrizität machen borreiche Verbindungen auch für Materialforschung und Anwendung attraktiv. Die größten wissenschaftlichen Herausforderungen bestehen jedoch weiterhin in der Synthese einphasiger Produkte in makroskopischen Mengen und in Form von Einkristallen, in der zweifelsfreien Identifizierung und Bestimmung von Zusammensetzung und Kristallstruktur sowie im Verständnis der elektronischen Situation. Verknüpfte Polyeder sind das dominierende Strukturelement in borreichen Verbindungen der Hauptgruppenelemente. In vielen Fällen leiten sich deren Strukturen von denen ab, die den Elementmodifikationen zugeschrieben werden. Auch diese bedürfen allerdings einer neuen, kritischen Durchsicht und Diskussion.

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LiB₁₂PC, the First Boron‐Rich Metal Boride with Phosphorus—Synthesis, Crystal Structure, Hardness, Spectroscopic Investigations

Vojteer

Sagawe

Stauffer

et al. 2011

Chemistry A European J

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We present synthesis, crystal structure, hardness, and IR/Raman and UV/Vis spectra of a new compound with the mean composition LiB(12)PC. Transparent single crystals were synthesised from Ga, Li, B, red phosphorus and C at 1500 °C in boron nitride crucibles welded in Ta ampoules. Depending on the type of boron used for the synthesis we obtained colourless, brown and red single crystals with slightly different P/C ratios. Colourless LiB(12)PC crystallizes orthorhombic in the space group Imma (No. 74) with a=10.188(2) Å, b=5.7689(11) Å, c=8.127(2) Å and Z=4. Brown LiB(12)P(0.89)C(1.11) is very similar, but with a lower P content. Red single crystals of LiB(12)P(1.13)C(0.87) have a larger unit cell with a=10.4097(18) Å, b=5.9029(7) Å, c=8.2044(12) Å. EDX measurements confirm that the red crystals contain more phosphorus than the other ones. The crystal structure is characterized by a covalent network of B(12) icosahedra connected by exohedral B-B bonds and P-P, P-C or C-C units. Li atoms are located in interstitials. The structure is closely related to MgB(7), LiB(13)C(2) and ScB(13)C. LiB(12)PC fulfils the electron counting rules of Wade and also Longuet-Higgins. Measurements of Vickers micro-hardness (H(V)=27 GPa) revealed that LiB(12)PC is a hard material. The optical band gaps obtained from UV/Vis spectra match the colours of the crystals. Furthermore we report on the IR and Raman spectra.

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Lithium Intercalation into β‐Rhombohedral Boron: LiB_∼10 or Li₃₀B₃₀₉?

Cited by 22 publications

References 31 publications

Boron: Elementary Challenge for Experimenters and Theoreticians

Boron: Elementary Challenge for Experimenters and Theoreticians

Bor – elementare Herausforderung für Experimentatoren und Theoretiker

LiB₁₂PC, the First Boron‐Rich Metal Boride with Phosphorus—Synthesis, Crystal Structure, Hardness, Spectroscopic Investigations

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Lithium Intercalation into β‐Rhombohedral Boron: LiB∼10 or Li30B309?

Cited by 22 publications

References 31 publications

Boron: Elementary Challenge for Experimenters and Theoreticians

Boron: Elementary Challenge for Experimenters and Theoreticians

Bor – elementare Herausforderung für Experimentatoren und Theoretiker

LiB12PC, the First Boron‐Rich Metal Boride with Phosphorus—Synthesis, Crystal Structure, Hardness, Spectroscopic Investigations

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Product

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About

Lithium Intercalation into β‐Rhombohedral Boron: LiB_∼10 or Li₃₀B₃₀₉?

LiB₁₂PC, the First Boron‐Rich Metal Boride with Phosphorus—Synthesis, Crystal Structure, Hardness, Spectroscopic Investigations