Chemical Bonding in Hypervalent Molecules Revised. Application of theAtoms in MoleculesTheoryto Y3X and Y3XZ (Y = H or CH3; X = N, P or As; Z = O or S) Compounds

1998 ◽  
Vol 120 (33) ◽  
pp. 8461-8471 ◽  
Author(s):  
J. A. Dobado ◽  
Henar Martínez-García ◽  
Molina ◽  
Markku R. Sundberg
Keyword(s):  
Chemical Bonding ◽  
Hypervalent Molecules

Chemical Bonding in Hypervalent Molecules:  Is the Octet Rule Relevant?

2002 ◽  
Vol 41 (8) ◽  
pp. 2164-2172 ◽  
Author(s):  
Stéphane Noury ◽  
Bernard Silvi ◽  
Ronald J. Gillespie
Keyword(s):  
Chemical Bonding ◽  
Hypervalent Molecules ◽  
Octet Rule

Localized-orbital locator (LOL) profiles of chemical bonding

2008 ◽  
Vol 86 (7) ◽  
pp. 695-702 ◽  
Author(s):  
Heiko Jacobsen
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Transition Metal Complexes ◽  
Chemical Bonding ◽  
Electron Pair ◽  
Kinetic Energy Density ◽  
Triple Bonds ◽  
Core Electrons ◽  
Localized Orbital ◽  
Hypervalent Molecules

We examine a recently introduced descriptor of chemical bonding, the localized-orbital locator (LOL), which is based on the kinetic-energy density (τ). Examples are presented for prototypical chemical bonds, such as single, double, and triple bonds, for bonding in transition metal complexes, for three-center two-electron bonds, as well as for hypervalent molecules. The topology of LOL is analyzed in terms of (3,–3) attractors (Γ). The influence of core electrons for chemical bonding is investigated, and a LOL-VSEPR (valence shell electron pair repulstion) relationship is established. Further, we compare LOL to the related electron localization function (ELF).Key words: chemical bonding, kinetic-energy density, localized-electron locator, VSEPR theory.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

Photocolouration of 2,4,4,6-Tetraaryl-4H-pyrans and Their Heteroanalogues: Importance of Hypervalent Photoisomers

1995 ◽  
Vol 60 (10) ◽  
pp. 1621-1633 ◽  
Author(s):  
Stanislav Böhm ◽  
Mojmír Adamec ◽  
Stanislav Nešpůrek ◽  
Josef Kuthan
Keyword(s):  
Reaction Kinetics ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Theoretical Data ◽  
Order Reaction ◽  
Bleaching Process ◽  
First Order ◽  
Photodegradation Products ◽  
Hypervalent Molecules

Molecular geometries of 2,4,4,6-tetraphenyl-4H-pyran (Ia), 4,4-(biphenyl-2,2e-diyl)-2,6-diphenyl-4H-pyran (Ib) and their heterocyclic isomers II-V were optimized by the PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made possible to select hypervalent molecules IIIa, IIIb, IVa and IVb being responsible for the photocolouration of 4H-pyrans Ia, Ib, while compounds Va, Vb, VI and VII come into account as possible photodegradation products. The bleaching process of the UV illuminated compound Ia is analyzed in terms of dispersive first-order reaction kinetics.

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