34
Chapter 2 Pauling “3-Electron Bonds”, 4-Electron 3-Centre Bonding, and the Need …
28. B. Braida, C. Walter, B. Engels and P.C. Hiberty, J. Amer. Chem. Soc. 132, 7631
(2010).
29. Y. Lan, S.E. Wheeler and K.N. Houk, J. Chem. Theory and Comp. 7, 2104 (2011).
Addendum Chapter 2
Unless stated otherwise, throughout this volume, the same atomic orbital is used to
accommodate electrons when the atomic orbital is both singly-occupied and
doubly-occupied. For example, for the valence-bond structures A B
and A B
,
the atomic orbital configurations are
2
1
(a) (b) and
1
2
(a) (b) ), respectively. This
gives the simplest form of theory that is needed to develop the increased-valence
theory. Procedures that can be used to go beyond this “minimal basis set”
approach, both by using four atomic orbitals, as in (a 1 )
2
(b 1 )
1 and (a 2 )
1 (b 2 )
2
, and six
atomic orbitals as in (a 1 )
1 (a 2 )
1 (b)
1 and (a)
1 (b 1 )
1 (b 2 )
1 , with a 1 -a 2 and b 1 -b 2 electronspin pairings, are described in ref. 30. The “breathing orbital” valence-bond
procedure
31 uses a different atomic orbital in a valence bond structure according to
the nature of the atomic formal charge, and as to whether the orbital is singly- or
doubly-occupied.
30. R.D. Harcourt, (a) J. Phys. Chem. A, 101, 2496, 5962 (1997). (b) in “Increased-valence
Structures in Quantum Chemical Methods in Main-Group Chemistry” (T.M. Klapötke
and A. Schulz, Wiley 1998), pp. 217-253. (c) in “Pauling's Legacy: Modern Modelling
of the Chemical Bond”, Theoretical and Computational Chemistry, Vol. 6 (Elsevier
Science B.V., Z.B. Maksić and W.J. Orville-Thomas editors, 1999) pp. 449-480.
31. S. Shaik and P.C. Hiberty, A Chemist’s Guide to Valence Bond Theory, (Wiley-Interscience, New York, 2008), p.249.
Chapter 2 Pauling “3-Electron Bonds”, 4-Electron 3-Centre Bonding, and the Need …
28. B. Braida, C. Walter, B. Engels and P.C. Hiberty, J. Amer. Chem. Soc. 132, 7631
(2010).
29. Y. Lan, S.E. Wheeler and K.N. Houk, J. Chem. Theory and Comp. 7, 2104 (2011).
Addendum Chapter 2
Unless stated otherwise, throughout this volume, the same atomic orbital is used to
accommodate electrons when the atomic orbital is both singly-occupied and
doubly-occupied. For example, for the valence-bond structures A B
and A B
,
the atomic orbital configurations are
2
1
(a) (b) and
1
2
(a) (b) ), respectively. This
gives the simplest form of theory that is needed to develop the increased-valence
theory. Procedures that can be used to go beyond this “minimal basis set”
approach, both by using four atomic orbitals, as in (a 1 )
2
(b 1 )
1 and (a 2 )
1 (b 2 )
2
, and six
atomic orbitals as in (a 1 )
1 (a 2 )
1 (b)
1 and (a)
1 (b 1 )
1 (b 2 )
1 , with a 1 -a 2 and b 1 -b 2 electronspin pairings, are described in ref. 30. The “breathing orbital” valence-bond
procedure
31 uses a different atomic orbital in a valence bond structure according to
the nature of the atomic formal charge, and as to whether the orbital is singly- or
doubly-occupied.
30. R.D. Harcourt, (a) J. Phys. Chem. A, 101, 2496, 5962 (1997). (b) in “Increased-valence
Structures in Quantum Chemical Methods in Main-Group Chemistry” (T.M. Klapötke
and A. Schulz, Wiley 1998), pp. 217-253. (c) in “Pauling's Legacy: Modern Modelling
of the Chemical Bond”, Theoretical and Computational Chemistry, Vol. 6 (Elsevier
Science B.V., Z.B. Maksić and W.J. Orville-Thomas editors, 1999) pp. 449-480.
31. S. Shaik and P.C. Hiberty, A Chemist’s Guide to Valence Bond Theory, (Wiley-Interscience, New York, 2008), p.249.