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Chapter 13 “Increased-Valence” Structures for N-Centre Bonding Units
13-9 Paramagnetic “Increased-Valence” Structures
All “increased-valence” structures that we have described in this Chapter are
appropriate when an even number of electrons is present in the N-centre bonding
unit. Therefore, they can be constructed for diamagnetic S = 0 spin-states· When
an odd number of electrons is involved in N-centre bonding, paramagnetic
“increased- valence” bonding units are also possible. The smallest of them pertain
for 3-electron 3-centre, 5-electron 4-centre and 7-electron 5-centre bonding. They
are exemplified in the “increased-valence” structures for (78) for CN 2 and the
bimolecular HO 3 and ONO 3 complexes that pertain for the
3
2
H O
HO O
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