Increased valence (qualitative valence bond) descriptions of the electronic structures of electron-rich fluorine-containing molecules [J. Fluorine Chem. 123 (2003) 5–20]

2004 ◽  
Vol 125 (5) ◽  
pp. 785 ◽  
Author(s):  
Richard D Harcourt ◽  
Thomas M Klapötke
Keyword(s):  
Electronic Structures ◽  
Valence Bond ◽  
Increased Valence

Corrigendum to: Valence Bond Formulations of Mechanisms for the Formation and Decomposition of N2O5

2006 ◽  
Vol 3 (6) ◽  
pp. 457 ◽  
Author(s):  
Richard D. Harcourt ◽  
Thomas M. Klapötke
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Phase Formation ◽  
Electronic Structures ◽  
Electron Pair ◽  
Valence Bond ◽  
Pair Bonds ◽  
Normal Electron ◽  
Stratospheric Clouds ◽  
Increased Valence

Environmental Context. N2O5 is an important nitrogen reservoir in polar stratospheric clouds found in Antarctica and involved with the ozone hole. Here we provide valence bond representations for the gas-phase formation and decomposition of this molecule. Abstract. Qualitative valence bond considerations are used to suggest how electronic reorganization could proceed for (a) the formation of N2O5 via the reactions NO2 + O3 → NO3 + O2, and NO2 + NO3 → N2O5, and (b) the thermal decomposition of N2O5 via the following sets of reactions: (i) N2O5 → NO2 + NO3, 2NO3 → O2NOONO2 → 2NO2 + O2; (ii) NO2 + NO3 → ONOONO2 → NO + O2 + NO2, NO + NO3 → 2NO2. Increased-valence structures, which possess one-electron bonds and fractional electron-pair bonds as well as 'normal' electron-pair bonds, are used to represent the electronic structures of the molecules.

Valence Bond Formulations of Mechanisms for the Formation and Decomposition of N2O5

2006 ◽  
Vol 3 (5) ◽  
pp. 355 ◽  
Author(s):  
Richard D. Harcourt ◽  
Thomas M. Klapötke
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Phase Formation ◽  
Electronic Structures ◽  
Electron Pair ◽  
Valence Bond ◽  
Pair Bonds ◽  
Normal Electron ◽  
Stratospheric Clouds ◽  
Increased Valence

Environmental Context. N2O5 is an important nitrogen reservoir in polar stratospheric clouds found in Antarctica and involved with the ozone hole. Here we provide valence bond representations for the gas-phase formation and decomposition of this molecule. Abstract. Qualitative valence bond considerations are used to suggest how electronic reorganization could proceed for (a) the formation of N2O5 via the reactions NO2 + O3 → NO3 + O2, and NO2 + NO3 → N2O5, and (b) the thermal decomposition of N2O5 via the following sets of reactions: (i) N2O5 → NO2 + NO3, 2NO3 → O2NOONO2 →2NO2 + O2; (ii) NO2 + NO3 → ONOONO2 → NO + O2 + NO2, NO + NO3 → 2NO2. Increased-valence structures, which possess one-electron bonds and fractional electron-pair bonds as well as ‘normal’ electron-pair bonds, are used to represent the electronic structures of the molecules.

Valence-bond studies of 4-electron 3-centre bonding units. I. The π-electrons of O3, NO2−, and CH2N2

1978 ◽  
Vol 56 (8) ◽  
pp. 1093-1101 ◽  
Author(s):  
Richard D. Harcourt ◽  
Walter Roso
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Valence Bond ◽  
Ground States ◽  
Wave Functions ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Electronic Mechanism ◽  
Increased Valence

Some ab-initio valence-bond wave-functions are reported for the π-electrons of the ground-states of O3, NO2−, and CH2N2. Examination of these wave-functions provides further support for the hypothesis that, for the ground-states of many electron-excess molecules, important valence-bond structures are those that are compatible with the electroneutrality principle, i.e. they carry either small or zero formal charges on each of the atoms. For O3 and CH2N2, the important valence-bond structures with zero atomic formal charges are [Formula: see text]Each of these structures has a 'long-bond' between non-adjacent atoms. The significance of 'long-bond' (or spin-paired diradical) structures for the electronic mechanism of 1,3-dipolar cycloaddition reactions is discussed and 'increased-valence' descriptions of the electronic structure of each molecule are presented. Some comments on the utility of 'increased-valence' structures are provided.

Valence Bond Studies of N5+

2002 ◽  
Vol 57 (9) ◽  
pp. 983-992 ◽  
Author(s):  
Richard D. Harcourta ◽  
Thomas M. Klapötkeb
Keyword(s):  
Valence Bond ◽  
Molecular Orbital Calculations ◽  
Energy Minimum ◽  
Localized Molecular Orbitals ◽  
Bond Lengths ◽  
Formal Charge ◽  
Valence Structure ◽  
Valence Bond Structure ◽  
Lewis Structures ◽  
Increased Valence

The results of STO-6G valence-bond studies are reported for the six π-electrons of C2v symmetry N5+, with π-electron core charges determined from the valence bond structures. Important types of canonical Lewis structures are calculated to carry either three atomic formal charges, arranged spatially as (+), (-) and (+) , as in or a single (+) atomic formal charge, as in the “long-bond” structure When localized molecular orbitals are used to accommodate bonding electrons between pairs of adjacent atoms, each of these types of Lewis structures, and others, are components of the increased-valence structure whose bond properties are in qualitative accord with experimental estimates of the bond lengths for N5+. Consideration is also given to other types of valence bond representations for N5+, and the results of MP2 molecular orbital calculations for the hypothetical N82+ are reported. For the latter species, a stable energy minimum with C2 symmetry is obtained. Its bond lengths are related to those implied by a Lewis-type valence-bond structure

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