Core Electron Topologies in Chemical Compounds: Case Study of Carbon versus Silicon. Issue 24 (23rd April 2018)

• Record Type: Journal Article
• Authors: Yoshida, Daisuke; Raebiger, Hannes; Shudo, Ken‐ichi; Ohno, Koichi
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 24(2018)
• Page Start: 7012
• Page End: 7018
• Publication Date: 2018-04-23
• Subjects: carbon -- electronic structure -- first-principles calculations -- hydrides -- silicon; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201713108
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The similarities and differences between carbon and silicon have attracted the curiosity of chemists for centuries. Similarities and analogies can be found in their saturated compounds, but carbon exhibits a cornucopia of unsaturated compounds that silicon (and most other elements) cannot replicate. While this qualitative difference is empirically well known, quantum chemistry has previously only described quantitative differences related to orbital overlap, steric effects, or orbital energies. We study C2 and Si2 and their hydrides X2 H2 n (X=C, Si; n =1, 2, 3) by first‐principles quantum chemical calculation, and find a qualitative difference in the topologies of the core electrons: carbon has the propensity to alter its core electron topology when forming unsaturated compounds, and silicon has not. We draw a connection between the core electron topologies and ionization energies, and identify other elements we expect to have similarly flexible core topologies as carbon. Abstract : Node in nodeless orbital : First‐principles calculation of C2, Si2, and their hydrides X2 H2 n reveal a striking difference in their electronic structures. The core electrons in C2 and its unsaturated hydrides alter their topology to stabilize centrosymmetric structures. For C2 this leads to the formation of a torus‐like ring in the 1σg orbital, separated by a node from the more familiar peanut‐like feature.