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From Wade-Mingos to Zintl-Klemm at 100 GPa: binary compounds of boron and lithium.
Hermann, Andreas; McSorley, Alexandra; Ashcroft, N W; Hoffmann, Roald.
Afiliación
  • Hermann A; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
J Am Chem Soc ; 134(45): 18606-18, 2012 Nov 14.
Article en En | MEDLINE | ID: mdl-23066852
Structural diversity and a variety of bonding schemes emerge as characteristics of the Li-B phase diagram in this ground-state theoretical investigation. We studied stoichiometries ranging from LiB(15) to Li(5)B, over a pressure range from 1 atm to 300 GPa. At P = 1 atm, stability is found for the experimentally known LiB(0.8-1.0), LiB(3), and Li(3)B(14) phases. As the pressure rises, the latter two structures are no longer even metastable, while the LiB(0.8-1.0) structures change in geometry and narrow their range of off-stoichiometry, eventually coming at high pressure to a diamondoid NaTl-type LiB. This phase then dominates the convex hull of stability. Other phases emerge as stable points at some pressure: LiB(4), Li(3)B(2), Li(2)B, and Li(5)B. At the boron-rich end, one obtains structures expectedly containing polyhedral motifs, and geometries are governed by Wade-Mingos electron counts; LiB(4) has a BaAl(4) structure. In the center and on the lithium-rich side of the phase diagram, Zintl-phase considerations, i.e., bonding between B(n-) entities, give us insight into the structures-tetrahedral B(-) networks in LiB; B pairs to isolated bonds in Li(5)B.

Texto completo: 1 Banco de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2012 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Banco de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2012 Tipo del documento: Article País de afiliación: Estados Unidos