Exploring the Nature of Silicon-Noble Gas Bonds in H3SiNgNSi and HSiNgNSi Compounds (Ng = Xe, Rn)

Int. J. Mol. Sci. 2015, 16(3), 6402-6418; doi:10.3390/ijms16036402

Author

Sudip Pan

, Ranajit Saha

 and Pratim K. Chattaraj * 

Department of Chemistry and Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur 721302, India

^*

Author to whom correspondence should be addressed. 

Academic Editor: Habil. Mihai V. Putz

Received: 11 February 2015 / Revised: 11 March 2015 / Accepted: 16 March 2015 / Published: 19 March 2015

(This article belongs to the Special Issue Chemical Bond and Bonding 2015)

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Abstract 

Ab initio and density functional theory-based computations are performed to investigate the structure and stability of H₃SiNgNSi and HSiNgNSi compounds (Ng = Xe, Rn). They are thermochemically unstable with respect to the dissociation channel producing Ng and H₃SiNSi or HSiNSi. However, they are kinetically stable with respect to this dissociation channel having activation free energy barriers of 19.3 and 23.3 kcal/mol for H₃SiXeNSi and H₃SiRnNSi, respectively, and 9.2 and 12.8 kcal/mol for HSiXeNSi and HSiRnNSi, respectively. The rest of the possible dissociation channels are endergonic in nature at room temperature for Rn analogues. However, one three-body dissociation channel for H₃SiXeNSi and one two-body and one three-body dissociation channels for HSiXeNSi are slightly exergonic in nature at room temperature. They become endergonic at slightly lower temperature. The nature of bonding between Ng and Si/N is analyzed by natural bond order, electron density and energy decomposition analyses. Natural population analysis indicates that they could be best represented as (H₃SiNg)⁺(NSi)⁻and (HSiNg)⁺(NSi)⁻. Energy decomposition analysis further reveals that the contribution from the orbital term (ΔE_orb) is dominant (ca. 67%–75%) towards the total attraction energy associated with the Si-Ng bond, whereas the electrostatic term (ΔE_elstat) contributes the maximum (ca. 66%–68%) for the same in the Ng–N bond, implying the covalent nature of the former bond and the ionic nature of the latter. View Full-Text

Keywords: ab initio study;  dissociation channels;  kinetic stability;  natural population analysis;  electron density analysis;  energy decomposition analysis

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