Abstract
STRUCTURAL studies with X rays1,2 of five and six-coordinated iron porphyrin complexes have shown that the distance from the iron atom to the nitrogen atoms of the porphyrin rings is less for low spin Fe(III) than for high spin Fe(III). As a result, it is often assumed that the Fe(III) atom is larger in its high spin state than in its low spin state. Similar size differences for the Fe(II) system form the basis of the Perutz model3 for the cooperativity of oxygen binding in haemoglobin. I discuss here the relative sizes of the high and low spin states of atoms in terms of the results of quantum mechanical calculations on isolated atoms. Contrary to earlier interpretations of structural studies, I have found that in the atoms I have studied the lowest lying high spin state of an atom in a given configuration is smaller than any state of lower spin.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Hoard, J. L., in Structural Chemistry and Molecular Biology (edit. by Rich, A., and Davidson, N.), (Freeman, San Francisco, 1968).
Countryman, R., Collins, D. M., and Hoard, J. L., J. Am. chem. Soc., 91, 5166–5167 (1969).
Perutz, M. F., Nature, 228, 726–734 (1970).
Coulson, C. A., Valence, second ed., 39 (Oxford University Press, London, 1961).
Perkins, J. F., J. chem. Phys., 39, 687–693 (1963).
Accad, Y., Pekeris, C. L., and Schiff, B., Phys. Rev., A 4, 516–536 (1971).
Clementi, E., IBM Jl Res. Dev., Suppl. 9 (1965).
Froese Fischer, C., J. Phys., B 5, 1302–1307 (1972).
Pauling, L., Nature of the Chemical Bond, third ed., 224 (Cornell University Press, Ithaca, 1960).
Boyd, R. J., and Coulson, C. A., J. Phys., B (GB), 6, 782–793 (1973), and references therein.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
BOYD, R. Relative sizes of high and low spin states of atoms. Nature 250, 566–567 (1974). https://doi.org/10.1038/250566a0
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1038/250566a0
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
