Wave-Functions and Valence-Bond Structures for 1-Electron Bonds, Electron-Pair Bonds, Pauling “3-Electron Bonds” and “No Bonds”

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.

Download Full-text

Charge-Shift Bonding—A Class of Electron-Pair Bonds That Emerges from Valence Bond Theory and Is Supported by the Electron Localization Function Approach

Chemistry - A European Journal ◽

10.1002/chem.200500265 ◽

2005 ◽

Vol 11 (21) ◽

pp. 6358-6371 ◽

Cited By ~ 169

Author(s):

Sason Shaik ◽

David Danovich ◽

Bernard Silvi ◽

David L. Lauvergnat ◽

Philippe C. Hiberty

Keyword(s):

Electron Pair ◽

Valence Bond ◽

Electron Localization Function ◽

Function Approach ◽

Electron Localization ◽

Valence Bond Theory ◽

Localization Function ◽

Pair Bonds ◽

Bond Theory ◽

Charge Shift

Download Full-text

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

Environmental Chemistry ◽

10.1071/en06058 ◽

2006 ◽

Vol 3 (5) ◽

pp. 355 ◽

Cited By ~ 1

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.

Download Full-text

Some wave functions for the four-electron threecentre bonding of four- and eight-π-electron systems

Australian Journal of Chemistry ◽

10.1071/ch9740691 ◽

1974 ◽

Vol 27 (4) ◽

pp. 691 ◽

Cited By ~ 33

Author(s):

RD Harcourt ◽

JF Sillitoe

Keyword(s):

Molecular Orbital ◽

Configuration Interaction ◽

Electron Pair ◽

Valence Bond ◽

Pair Bond ◽

Wave Functions ◽

Electron Systems ◽

Numerical Evidence ◽

The One ◽

Increased Valence

For symmetrical four-electron three-centre bonding units, the standard valence-bond (VB), delocalized molecular orbital (MO), increased-valence (IV) and non-paired spatial orbital (NPSO) representations of the electrons are Diagram O3, NO2- and CF2 with four π-electrons, and N3-, CO2 and NO2+ with eight π-electrons, have respectively one and two four-electron three-centre bonding units for these n-electrons. By means of Pople-Parr-Pariser type approximations, the MO, standard VB, IV and NPSO wave functions for these systems are compared with complete VB (or best configuration interaction) wave functions for the ground states. Similar studies are reported for the n-electrons of N2O. Further demonstration is given for the important result obtained elsewhere that the IV formulae must always have energies which are lower than those of the standard VB formulae, provided that the same technique is used to construct electron-pair bond wave functions. The extra stability arises because IV formulae summarize resonance between the standard VB formulae and long-bond formulae of the type Diagram As has been discussed elsewhere, the latter structure can make appreciable contributions to the complete VB resonance when its atomic formal charges are either zero or small in magnitude.If two-centre bond orbitals are used to construct the wave functions for the one-electron bond(s) and the two-electron bond(s) of IV formulae, then the IV and MO wave functions are almost identical for the symmetrical systems. Further numerical evidence is provided for this near-equivalence.

Download Full-text

Valence Bond Structures for the N3- Anion, the N3 Radical and the N6- Radical Anion

Zeitschrift für Naturforschung B ◽

10.5560/znb.2012-0161 ◽

2012 ◽

Vol 67 (9) ◽

pp. 935-943 ◽

Cited By ~ 2

Author(s):

Richard D. Harcourta ◽

Thomas M. Klapötke

Keyword(s):

Radical Anion ◽

Electron Pair ◽

Atomic Orbital ◽

Valence Bond ◽

Wave Functions ◽

The One ◽

Lewis Structures ◽

Increased Valence ◽

Polarity Parameters

With Heitler-London atomic orbital-type formulations of the wave functions for (fractional) electron-pair πx(NN) and πy(NN) bonds, increased-valence structures for the N3- anion and N3- radical are equivalent to resonance between familiar standard Lewis structures and singlet diradical (or “long-bond”) Lewis structures. Theory is developed for the calculation of the polarity parameters that are associated with the one-electron πx(NN) and πy(NN) bonds in the increased-valence structures, and illustrative STO-6G estimates of their values are reported. They show that the πx and πy electrons of these bonds are strongly charge-correlated relative to each other. The increased-valence structures for the N3- anion and the N3- radical are used to help construct increased-valence structures for the N6- radical anion with C2h symmetry

Download Full-text