Polyanionic Hexagons: X6n– (X = Si, Ge)

Takahashi, Masae

doi:10.3390/sym2041745

Cited by 7 publications

(6 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar to La 2 Zn 5 Sn, the 4s and 4p bands of Zn are highly dispersive due to the remarkably wide range of Zn–Zn distances. On the other hand, there is no significant overlap between the 5s and 5p bands of Sn, and this confirms the lack of s–p hybridization. , The sharp spike around −9 eV in the DOS for La 7 Zn 21 Pb 2 (see Supporting Information) corresponds to the 6s 2 lone pair of Pb, and is another testament to this conjecture.…”

Section: Resultsmentioning

confidence: 65%

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Suen

Bobev

2013

Inorg. Chem.

View full text Add to dashboard Cite

Reported are 11 new ternary phases with the general formula RE7Zn21Tt2 (RE = La-Nd; Tt = Ge, Sn, and Pb), synthesized from the respective elements by reactions at high temperature. Their structures, established on the basis of single-crystal and powder X-ray diffraction work, are shown to be a new structure type with the orthorhombic space group Pbam (No. 55, Pearson symbol oP60). This complex atomic arrangement features condensed polyhedra made up of Zn atoms, interspersed by Ge, Sn, or Pb atoms in trigonal-planar coordination. The structure bears resemblance with the La3Al11 and the LaRhSn2 structure types, which are compared and discussed. Temperature dependent dc magnetization measurements confirm RE(3+) ground states for all rare-earth elements, and the expected local-moment magnetism due to the partial filling of their 4f states for RE(3+) = Ce(3+), Pr(3+), and Nd(3+). Theoretical considerations of the electronic structure based on the tight-binding linear muffin-tin orbital (TB-LMTO-ASA) method are also presented: the calculations support the experimental observation of a small, but not negligible, homogeneity range in RE7Zn(21+x)Tt(2-x) (x < 0.5). The partial substitution of the tetrel atoms by the electron-poorer Zn appears to be an important attribute, leading to an optimal valence electron concentration and, thereby, to the overall electronic stability of the crystal structure of this family of polar intermetallics.

show abstract

Section: Resultsmentioning

confidence: 65%

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Suen

Bobev

2013

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…We previously discovered a similar flat silicon hexagon with double aromaticity, i.e., the dianion of the Si 6 cluster (Fig. 1d) 25, 26 . This finding encouraged us to design the present flat silicene building blocks using electron-donating substituents.…”

Section: Introductionmentioning

confidence: 77%

Flat building blocks for flat silicene

Takahashi

2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

Silicene is the silicon equivalent of graphene, which is composed of a honeycomb carbon structure with one atom thickness and has attractive characteristics of a perfect two-dimensional π-conjugated sheet. However, unlike flat and highly stable graphene, silicene is relatively sticky and thus unstable due to its puckered or crinkled structure. Flatness is important for stability, and to obtain perfect π-conjugation, electron-donating atoms and molecules should not interact with the π electrons. The structural differences between silicene and graphene result from the differences in their building blocks, flat benzene and chair-form hexasilabenzene. It is crucial to design flat building blocks for silicene with no interactions between the electron donor and π-orbitals. Here, we report the successful design of such building blocks with the aid of density functional theory calculations. Our fundamental concept is to attach substituents that have sp-hybrid orbitals and act as electron donors in a manner that it does not interact with the π orbitals. The honeycomb silicon molecule with BeH at the edge designed according to our concept, clearly shows the same structural, charge distribution and molecular orbital characteristics as the corresponding carbon-based molecule.

show abstract

“…It was theoretically predicted that the Si 6 monocyclic backbone retains planar geometry when all H atoms were substituted by Li atoms . Si 6 n − ( n= 2, 4, and 6) and (SiBeH) 6 are the other theoretically known compounds possessing planar Si 6 monocyclic backbone . Exploration of the PES of Si 6 Li 6 showed that the Si 6 Li 6 monocyclic structure was not the global minimum on the PES .…”

Section: Figurementioning

confidence: 99%

“…[29,30] Si 6 nÀ (n = 2, 4, and 6) and (SiBeH) 6 are the other theoretically known compounds possessing planar Si 6 monocyclic backbone. [31][32][33] Exploration of the PES of Si 6 Li 6 showedt hat the Si 6 Li 6 monocyclic structure was not the global minimum on the PES. [34] It would therefore be an interesting subject to evaluate kinetic stability of the Si 6 Li 6 monocyclic structure.In this study,w eh ave designed ak inetically stable hexasilabenened erivative with ap lanar,m onocyclic Si 6 backbone.…”

mentioning

confidence: 99%

Designing the Backbone of Hexasilabenzene Derivatives with a High Unimolecular Kinetic Stability

Sumiya

Maeda

2018

Chemistry A European J

View full text Add to dashboard Cite

It is an important subject to theoretically predict the kinetic stability of transient species. In this study, we have studied the kinetic stability of hexasilabenzene Si H and its derivatives, that is, decasilanaphthalene Si H and Li-substituted hexasilabenzene Si Li , theoretically by the artificial force induced reaction (AFIR) method combined with the rate constant matrix contraction (RCMC) method. Molecular design was further conducted to extend the unimolecular lifetime of hexasilabenzene derivatives. Although both Si H and Si Li were shown to possess shorter lifetimes than Si H , we found that the lifetimes of Si Li changed depending on arrangements of Li atoms around the monocyclic Si backbone. Based on this knowledge, we found that a compound of an atomic composition Si H Li with a planar, monocyclic Si backbone has a relatively long unimolecular lifetime. Moreover, substitution of the two Li atoms by Na atoms further increased the lifetime.

show abstract

Polyanionic Hexagons: X6n– (X = Si, Ge)

Cited by 7 publications

References 70 publications

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Flat building blocks for flat silicene

Designing the Backbone of Hexasilabenzene Derivatives with a High Unimolecular Kinetic Stability

Contact Info

Product

Resources

About

Polyanionic Hexagons: X6n– (X = Si, Ge)

Cited by 7 publications

References 70 publications

Synthesis and Structural Characterization of RE7Zn21Tt2 (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Synthesis and Structural Characterization of RE7Zn21Tt2 (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Flat building blocks for flat silicene

Designing the Backbone of Hexasilabenzene Derivatives with a High Unimolecular Kinetic Stability

Contact Info

Product

Resources

About

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases

Synthesis and Structural Characterization of RE₇Zn₂₁Tt₂ (RE = La–Nd; Tt = Ge, Sn, and Pb): New Structure Type Among the Polar Intermetallic Phases