On the Bonding in Carbosilanes

Savin, Andreas; Flad, Heinz-Jürgen; Flad, J.; Preuß, H.; Schnering, Hans Georg̀ von

doi:10.1002/anie.199201851

Cited by 155 publications

(72 citation statements)

References 15 publications

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“…The ELF was evaluated according to ref. [24] with an ELF module implemented in VASP. The topology of ELF was visualized by STM3 toolkit.…”

Section: à3mentioning

confidence: 99%

“…ELF is based on the Hartree-Fock pair probability of parallel spin electrons and can be calculated in density functional theory from the excess kinetic energy [14] density due to Pauli-repulsion. [24,25] This function produces easily understandable, pictorially informative patterns of chemical bonding and is widely used to describe and visualize chemical bonding in molecules and solids.…”

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confidence: 99%

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Transition Metal Borides: Superhard versus Ultra‐incompressible

2008

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The terms superhard and ultra-incompressible are commonly used to describe a material's hardness and compressibility approaching the properties of diamond, the hardest and most incompressible single-phase material known so far. Superhard and ultra-incompressible materials are of great interest for applications as well as for basic research. The materials are widely used in various industrial applications, e.g., such as cutting tools or wear-resistant coatings. Basic research focuses on the understanding of structure-property relationships, which yields hints for the design of new superhard and ultra-incompressible materials. Attempts to synthesize or theoretically predict new superhard and ultraincompressible materials are the subject of intensive current research activities. Experimentally accessible and predicted single-phase materials can be classified into three groups: [1] i) crystalline and disordered carbon modifications, ii) compounds formed by the light elements B, C, N, O, and Si, and iii) compounds of transition metals (TMs) with light elements B, C, N, or O. As another more recently developed group of superhard materials, the nanocomposites as multiphase materials have to be mentioned. Most of the materials of classes (i) and (ii) have to be synthesized under extreme conditions. Although these processes are difficult and expensive, materials of these classes have become the most used hard materials for applications (like c-BN and synthetic diamond). The third class of compounds, especially TM carbides and borides, can be synthesized in a comparably facile way at ambient pressure in an arc furnace. Two design parameters are of importance for the selection of superhard or ultra-incompressible TM compounds, [2] i.e., a high electron concentration (EC, electrons per atomic volume) of the TM and the presence of directional covalent bonding. High ECs can be found among the heavy TMs, whereas carbon and boron form short covalent bonds. Among the TMs, 5d metals of groups 6-9, i.e., W, Re, Os, and Ir are the most promising candidates as they show the highest ECs, small atomic volume, and high bulk modulus. Very recently, the properties of several TM borides with high hardness and bulk modulus were studied experimentally and theoretically. [3][4][5][6][7] ReB 2 and OsB 2 were found to be superhard and ultra-incompressible, while OsB was predicted to be ultra-incompressible.In this study, we will focus on boron-rich compounds of the systems Ru-B, Os-B, and W-B. These systems have been investigated for several decades, [7][8][9][10][11]

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“…The ELF was evaluated according to ref. [24] with an ELF module implemented in VASP. The topology of ELF was visualized by STM3 toolkit.…”

Section: à3mentioning

confidence: 99%

mentioning

confidence: 99%

Transition Metal Borides: Superhard versus Ultra‐incompressible

2008

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“…Finally, we use another closely related quantity -the electron localization function (ELF) introduced by Becke and Edgecombe [12] and refined and applied by Savin, Silvi, and Kohout [13][14][15] to obtain a pictorial representation of the underlying metal-ligand bonding interactions. The topological analysis of the electron localization function [16a-16c] is intended to provide a direct space mathematical model to the Lewis theory and the valence state electron pair repulsion (VSEPR) model of Gillespie and Nyholm.…”

Section: Introductionmentioning

confidence: 99%

Chemical Bonding in Molecules and Complexes Containing d-Elements Based on DFT

Atanasov

Daul

Fowe

2005

Monatshefte für Chemie

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Summary. Metal-ligand bonding in transition metal halide molecules and complexes with different central ions, oxidations states, and coordination numbers: Cr III X 6 3À , Cr IV X 4 , Cr II X 2 (X ¼ F,Cl,Br,I),3þ (M ¼ Cr,Co) and Re 2 Cl 8 2À has been studied in terms of the Extended Transition State (ETS) energy patitioning scheme within the DFT and electron density analysis (the Laplacian of the electron density and the electronic localization function). Bonding is found to be dominated by ionicity in all cases, especially so for complexes with higher coordination numbers. Covalent contributions to the metal-ligand bond are found to be mainly due to the ndelectrons and to lesser extent due to the metal (n þ 1)s and (n þ 1)p-orbitals, contributions from (n þ 1)s increasing when going to lower coordination numbers. Metal-ligand bonding analysis have been used in order to check some concepts emerging from ligand field theory when applied to the spectroscopy and magnetism of transition metal complexes. It is pointed out that for complexes of high symmetry (MX 6 , O h , MX 4 , T d , and MX 2 , D 1h ) electron density analyses gain interpretative power when partitioned into contributions from occupied orbitals of different symmetry.

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“…The electron localization function (ELF) was evaluated according to [12] with an ELF module already implemented within the TB-LMTO-ASA program package [9]. To gain a deeper insight into the chemical bonding, the topology of ELF was analysed with the program Basin [13].…”

Section: Methodsmentioning

confidence: 99%

The Co₂Al₉ Structure Type Revisited.

Bostroem¹,

Rösner²,

Prots³

et al. 2005

ChemInform

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Abstract. The centrosymmetric structure of Co 2 Al 9 (space group P2 1 /c, Pearson symbol mP22), the isotypic structures of Rh 2 Al 9 and Ir 2 Al 9 and the slightly distorted acentric structures of Rh 2 Ga 9 and Ir 2 Ga 9 (space group Pc) were reinvestigated from single crystal X-ray diffraction data. The structure of Rh 2 Ga 9 represents a new structure type. The difference between the aluminides and the galDer Strukturtyp Co 2 Al 9 erneut untersucht Inhaltsübersicht. Die zentrosymmetrische Struktur der Verbindung Co 2 Al 9 (Raumgruppe P2 1 /c, Pearson-Symbol mP22), die isotypen Strukturen Rh 2 Al 9 und Ir 2 Al 9 , sowie die leicht verzerrten azentrischen Strukturen Rh 2 Ga 9 und Ir 2 Ga 9 (Raumgruppe Pc) wurden auf der Basis der Einkristall-Röntgenbeugungsdaten erneut unter-

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On the Bonding in Carbosilanes

Cited by 155 publications

References 15 publications

Transition Metal Borides: Superhard versus Ultra‐incompressible

Transition Metal Borides: Superhard versus Ultra‐incompressible

Chemical Bonding in Molecules and Complexes Containing d-Elements Based on DFT

The Co₂Al₉ Structure Type Revisited.

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On the Bonding in Carbosilanes

Cited by 155 publications

References 15 publications

Transition Metal Borides: Superhard versus Ultra‐incompressible

Transition Metal Borides: Superhard versus Ultra‐incompressible

Chemical Bonding in Molecules and Complexes Containing d-Elements Based on DFT

The Co2Al9 Structure Type Revisited.

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Product

Resources

About

The Co₂Al₉ Structure Type Revisited.