84
Chapter 6 Pauling “3-Electron Bonds”, 5-Electron 3-Centre Bonding …
also have Pauling “3- electron bonds”. The presence of non-bonding electrons on
the A atoms of each the structures (40)-(44) is in accord with the prediction that
these 25 valence-electron radicals are non-planar
10 .
Using ClO 2 as the example, the Addendum 2014 provides an alternative, non dorbital approach that can be used to reduce the magnitudes of the atomic formal
charges of valence-bond structures (30), (31), (41) and (42) for ClO 2 , ClO 3 and
SO 3
- .
Group (V) trihalides are isoelectronic with
3
3
PO
,
2
3
SO
and
3
ClO
. Photoelectron spectrum studies permit features of the electronic structures of different
states for the singly-charged cations of the trihalides to be examined
11
. If a nonbonding electron is ionized, a Pauling “3-electron bond” can be developed, as is
displayed in structure (45) for the cation
3
NCl
. These types of valence-bond
structures are similar to structures (40)-(42) for
2
3
PO
,
3
SO
and
3
ClO .
The influence of overlap on the stabilization or destabilization of Pauling “3electron bonds” has been discussed in Section 3-10, together with the consequent
effect on competition between planarity and pyramidalization for radicals such as
3
CH ,
2
CH F ,
2
CHF and
3
CF . Each of
3
CF and
3
NCl
has 25 valence-shell
electrons.
References
1. G.R. Bird, J.C. Baird, A.W. Jache, J.A. Hodgeson, R.F. Curl, A.C. Kunckle, J.W.
Bransford, J. Rastrup-Andersen and J. Rosenthal, J. Chem. Phys., 40, 3378 (1964).
2. L. Pauling, The Nature of the Chemical Bond (Cornell, 1960), p. 348.
3. M. Green and J.W. Linnett, J. Chem. Soc., 4959 (1960).
4. M.R. Truter, D.W.J. Cruickshank and G.A. Jeffrey, Acta Cryst., 13, 855 (1960).
5. M.R. Truter, Acta Cryst., 7, 73 (1954).
6. P.H. Turner and A.P. Cox, Chem. Phys. Letters, 39, 585 (1976).
7. R.D. Harcourt, J. Chem. Soc. Faraday Trans. 87, 1089 (1991).
8. M. Green, J. Chem. Soc. 2819 (1962).
9. R.D. Harcourt, (a) Theor. Chim. Acta, 2, 437 (1964); 4, 202 (1966); (b) Int. J. Quantum
Chem., 4, 173 (1970).
10. J.R. Morton, Chem. Revs., 64, 453 (1964).
11. D. Colbourne, D.C. Frost, C.A. McDowell and N.P.C. Westwood, J. Chem. Phys. 69,
1078 (1978).
Chapter 6 Pauling “3-Electron Bonds”, 5-Electron 3-Centre Bonding …
also have Pauling “3- electron bonds”. The presence of non-bonding electrons on
the A atoms of each the structures (40)-(44) is in accord with the prediction that
these 25 valence-electron radicals are non-planar
10 .
Using ClO 2 as the example, the Addendum 2014 provides an alternative, non dorbital approach that can be used to reduce the magnitudes of the atomic formal
charges of valence-bond structures (30), (31), (41) and (42) for ClO 2 , ClO 3 and
SO 3
- .
Group (V) trihalides are isoelectronic with
3
3
PO
,
2
3
SO
and
3
ClO
. Photoelectron spectrum studies permit features of the electronic structures of different
states for the singly-charged cations of the trihalides to be examined
11
. If a nonbonding electron is ionized, a Pauling “3-electron bond” can be developed, as is
displayed in structure (45) for the cation
3
NCl
. These types of valence-bond
structures are similar to structures (40)-(42) for
2
3
PO
,
3
SO
and
3
ClO .
The influence of overlap on the stabilization or destabilization of Pauling “3electron bonds” has been discussed in Section 3-10, together with the consequent
effect on competition between planarity and pyramidalization for radicals such as
3
CH ,
2
CH F ,
2
CHF and
3
CF . Each of
3
CF and
3
NCl
has 25 valence-shell
electrons.
References
1. G.R. Bird, J.C. Baird, A.W. Jache, J.A. Hodgeson, R.F. Curl, A.C. Kunckle, J.W.
Bransford, J. Rastrup-Andersen and J. Rosenthal, J. Chem. Phys., 40, 3378 (1964).
2. L. Pauling, The Nature of the Chemical Bond (Cornell, 1960), p. 348.
3. M. Green and J.W. Linnett, J. Chem. Soc., 4959 (1960).
4. M.R. Truter, D.W.J. Cruickshank and G.A. Jeffrey, Acta Cryst., 13, 855 (1960).
5. M.R. Truter, Acta Cryst., 7, 73 (1954).
6. P.H. Turner and A.P. Cox, Chem. Phys. Letters, 39, 585 (1976).
7. R.D. Harcourt, J. Chem. Soc. Faraday Trans. 87, 1089 (1991).
8. M. Green, J. Chem. Soc. 2819 (1962).
9. R.D. Harcourt, (a) Theor. Chim. Acta, 2, 437 (1964); 4, 202 (1966); (b) Int. J. Quantum
Chem., 4, 173 (1970).
10. J.R. Morton, Chem. Revs., 64, 453 (1964).
11. D. Colbourne, D.C. Frost, C.A. McDowell and N.P.C. Westwood, J. Chem. Phys. 69,
1078 (1978).