Does the 18-Electron Rule Apply to CrSi12?

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• 作者：Marissa Baddick Abreu ; Arthur C. Reber ; Shiv N. Khanna
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2014
• 出版时间：October 16, 2014
• 年：2014
• 卷：5
• 期：20
• 页码：3492-3496
• 全文大小：315K
• ISSN：1948-7185

文摘

Understanding the bonding between silicon and transition metals is valuable for devising strategies for incorporating magnetic species into silicon. CrSi₁₂ is the standard example of a cluster whose apparent high stability has been explained by the 18-electron rule. We critically examine the bonding and nature of stability of CrSi₁₂ and show that its electronic structure does not conform to the 18-electron rule. Through theoretical studies, we find that CrSi₁₂ has 16 effective valence electrons assigned to the Cr atom and an unoccupied 3d_z² orbital. We demonstrate that the cluster鈥檚 apparent stability is rooted in a crystal field-like splitting of the 3d orbitals analogous to that of square planar complexes. CrSi₁₄ is shown to follow the 18-electron rule and exhibits all conventional markers characteristic of a magic cluster.

Keywords:

18-electron rule; silicon clusters; silicon encapsulated transition-metal clusters; magic clusters