1. L. Pauling, The Nature of the Chemical Bond, (Cornell University Press, Ithaca, 1960), p. 162.
2. 2. For a summary and criticisms of these valence-bond theories, see (a) F.A. Cotton, Chemical Applications of Group Theory, 1st Edition (Interscience, New York, 1963), p. 222
3. (b) J.E. Huheey, Inorganic Chemistry, (Harper and Row, 1978), p. 342.
4. D.K. Hoffman, K. Ruedenberg and J.G. Verkade, Structure and Bonding, 33, 57 (1977).
5. R.D. Harcourt and G.R. Scollary, Inorg. Nucl. Chem. Letters, 11, 821 (1975).