Molecular-orbital model for

Scheme la shows the approximate molecular orbital model for the hypervalent X-E-X 3c-4e in EX4, such as SC14. Characters of the three molecular orbitals are bonding (v /i), nonbonding (v /2), and anti-bonding (v /3). Two electrons are in and two in v 2. Electrons in v 2 localize on X of X-E-X and the hypervalent bonds are mainly characterized by v 2. Consequently,... 

The hypervalent chalcogen chemistry has been developed to higher coordinated species with various ligands,7 10 where TBP changes to square pyramidal (SP) or octahedral (Oh), etc. Additional atomic orbitals of E, such as an 5-orbital, may operate to stabilize the structures.10b The concept is also extended over linear a-bonds constructed by m ( > 4) atoms with n electrons (extended hypervalent bonds mc-ne (in > 4)).11 14 The approximate molecular orbital model for mc-ne (m > 4) is also exhibited in Scheme la, exemplified by 4c-6e. 

Dahl has employed (37, 85) a qualitative molecular orbital model for [Fe4S4L4] complexes based on Td symmetry, the essential features of which are summarized in Fig. 13. The 20 iron d orbitals form molecular orbitals which can be divided into three major groups. The first group,... 

FIGURE 4. Qualitative molecular orbital model for the E—E bonding in (a) planar and (b) trans-bent H2E=EH2... 

MOLECULAR ORBITAL MODEL FOR CYCLIC CONJUGATED MOLECULES... 

Fig. 4.6. A molecular orbital model for the electronic structure of different bonding states of selenium, illustrating the valence alternation defects, Sej" and Se,. ...

Although the extended valence bond PKS model probably can always be shown to be equivalent to a molecular orbital model for mixed valency systems involving complex bridging ligands such as found in the Creutz-Taube ion, these systems are best treated using a MO approach. A qualitative description is now given of the MO ideas developed by Piepho. ... 

Compare the description of the localized electron model (Lewis structure) with that of the molecular orbital model for the bonding in NO, NO+, and NO-. Account for any discrepancies between the two models. 

Fig. 9.3 Molecular orbital model for different particle sizes. (After ref. [84])...

Molecular Orbital Model for the Lowest-Energy One-Electron Excitations... 

Jorgensen, C. K. (1964) A simple molecular orbital model for transition metal complexes. J. Chem. Soc. 6226. 

Molecular Orbital Models for Structures Involving Two, Four... 

Soules TF, Davis TS, Kreidler ER (1971) Molecular orbital model for antimony luminescent centers in fluorophosphates. J ChemPhys 55 1056-1064... 

In the simple molecular orbital model for the lowest excited states of these molecules, the primary difference between the homo- and hetero-bischelated complexes is in the localization of the excitation energy in the latter. In this section we associate this localization of energy with the failure of the lowest excited states of the hetero-bischelated complexes to... 

The frontier molecular orbital model for donor-acceptor complexes provides a convenient framework for a discussion of hydrogen bonding and receptor-guest interactions. 

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