Pauling and orbitals

[Wai-To Chan <chan at.at curl.gkcl.yorku.ca>]

     I don't see how Pauling's statement, when considered in the context
 of his J Chem Ed article, can be viewed as naive philosophicaly or
 scientificaly.
 Consider what you think how Gilbert Lewis should respond when asked
 if electron-pairs exist.
 Granted that Lewis could be excused for not knowing quantum
 mechanics which preclude spatial localization of two electrons
 he must have known the coulomb's law for repulsion between
 electrons. Yet we have been using Lewis model to explain much of
 descriptive chemistry to this day. We also use aufbau principle
 to rationalize the periodic table when we know that these
 K, L, M and N shells and S, P, D and F wavefunctions
 don't exist; or at least they don't exist for all elements
 beyond hydrogen.  But then our concept of valence shells/orbitals
 based on aufbau principle is very much in line with the
 chemical periodicity of elements. The Lewis electron-pair model
 has a validity that seem to transcend our understanding
 of QM. Hence, in spite of its not being a physical entity
 we continue to apply it to interpretation of chemical reactivity
 in such a manner as to imply its 'existence'.
 In light of this I think it is not unreasonable to
 say that electron-pairs/orbitals exist.
 Wai-To Chan
 Eric Scerri (scerri at.at chem.ucla.edu) wrote:
 <<<<<<<<<<<<<<<<<<<<<<<<<
 THe original question which started this thread was partly about Pauling's
 OWN views about hybridization and orbitals.
 I think Pauling was surprisingly naive philosophically when it came to
 interpretation of what he was doing.  I base this on the following personal
 anecdote.  When the debate with Ogilvie was taking place in J. Chem. Ed.
 the same issue that carried the Pauling response also included three other
 reponses including a brief piece by myself.  I used this as an excuse to
 get in touch with Pauling to try to explore his view further.  In his reply
 he said almost verbatim,
 "Orbitals clearly exist since Mulliken and I have been writing about them
 for the past 60 years"
 I could not resist replying that storytellers have also been writing about
 unicorns for many years.
 Dr. Eric R. Scerri
 >>>>>>>>>>>>>>>>>>>>