d-Orbitals in the Chemistry of Silicon, Phosphorus and Sulfur

Kwart, Harold; King, Kenneth F.

doi:10.1007/978-3-642-46342-6

Cited by 115 publications

(39 citation statements)

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“…In addition, the C-OH groups are more difficult to dissociate than silanol groups, in other words, the acidity of silanol groups is higher than that of carbinol groups [38], so that, a reduced EOF is observed using Carbowax 20M coatings.…”

Section: Discussion On Influence Of Surface Treatment On Eofmentioning

confidence: 99%

The influence of surface treatments on the electroosmotic flow in micellar electrokinetic capillary chromatography

Claessens

Cramers

1992

Chromatographia

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Section: Discussion On Influence Of Surface Treatment On Eofmentioning

confidence: 99%

The influence of surface treatments on the electroosmotic flow in micellar electrokinetic capillary chromatography

Claessens

Cramers

1992

Chromatographia

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“…3d für Silicium) erklärt. [33] Silicium ist aber kein Übergangsmetall, und inzwischen ist allgemein anerkannt, dass die 3d-Orbitale am Silicium zu diffus sind, um eine ausreichend starke Bindung einzugehen. [34] Die Erweiterung der Koordinationssphäre beruht beim Silicium auf der Fähigkeit der 3p-Orbitale, elektronenreiche Drei-Zentren-vier-Elektronen-Bindungen einzugehen.…”

Section: Analyse Der Hypervalenzbindungunclassified

Lewis‐Base‐Katalyse in der organischen Synthese

2008

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Das Erbe von Gilbert Newton Lewis (1875–1946) ist im Wörterbuch der chemischen Bindung und Reaktivität allgegenwärtig. Die Bedeutung seines Konzepts der Donor‐Akzeptor‐Bindung kommt in den eponymen Grundbegriffen für Elektronenpaarakzeptoren (Lewis‐Säuren) und ‐donoren (Lewis‐Basen) zum Ausdruck. Lewis erkannte, dass Säuren nicht automatisch Wasserstoff enthalten müssen (Brønsted‐Säuren) und trug so zum Sturz des “modernen Protonenkults” bei. Seine Entdeckung läutete zunächst die Entwicklung von Lewis‐Säuren als Reagentien und Katalysatoren für organische Reaktionen ein, in den letzten Jahren wurde aber offensichtlich, dass für diese Zwecke auch Lewis‐Basen eingesetzt werden können. Bezüglich der Beschleunigung chemischer Reaktionen ergänzen Lewis‐Basen die entsprechenden Lewis‐Säuren nicht nur elektronisch: Tatsächlich können Lewis‐Basen die Elektrophilie wie auch die Nucleophilie der Verbindungen verstärken, an die sie gebunden werden. Diese unterschiedliche Reaktivität resultiert in einer bemerkenswerten Vielfalt Lewis‐Base‐katalysierter Reaktionen.

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“…of a total of 56 atoms of which eight cations ͑Si, Ge, Sn͒ are in tetrahedral ͑fourfold coordinated to N͒ and 16 in octahedral ͑sixfold coordinated to N͒ sites, whereas nitrogen is fourfold coordinated to the cations. In the past, a higher coordination number of silicon in some organosilicon compounds has been attributed to the participation of the 3d orbitals in the hybridization with 2s and 2p, 49 but more recently this concept has been questioned by several authors ͑see Ref. 50 for a review͒.…”

Section: A Stability Of the Relaxed Interfacesmentioning

confidence: 99%

Electronic structure, stability, and mechanism of the decohesion and shear of interfaces in superhard nanocomposites and heterostructures

2009

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Electronic structure of interfaces, their stability and the mechanism of decohesion in tension as well as of ideal shear have been studied by means of ab initio density-functional theory for heterostructures consisting of a few nanometer thick fcc͑NaCl͒-TiN slabs with one monolayer of pseudomorphic SiN interface. It is found that the SiN interface sandwiched between fcc͑001͒-TiN slabs is unstable in its symmetric fcc structure, but it stabilizes by distortion of the Si-N bonds, which lowers the symmetry. Significant strengthening of the SiN interface occurs due to partial transfer of valence charge to the Si containing interface which induces damped valence charge-density oscillations propagating into the TiN bulk. As a consequence of these oscillations, decohesion, and ideal shear does not occur within the SiN interface, but in the TiN slabs between the Ti-N planes parallel to that interface. We provide a detailed study of this mechanism of decohesion and ideal shear on the atomic scale. The results are discussed in the context of the experimentally found hardness enhancement in heterostructures and superhard nanocomposites.

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d-Orbitals in the Chemistry of Silicon, Phosphorus and Sulfur

Cited by 115 publications

References 0 publications

The influence of surface treatments on the electroosmotic flow in micellar electrokinetic capillary chromatography

The influence of surface treatments on the electroosmotic flow in micellar electrokinetic capillary chromatography

Lewis‐Base‐Katalyse in der organischen Synthese

Electronic structure, stability, and mechanism of the decohesion and shear of interfaces in superhard nanocomposites and heterostructures

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