Theoretica chimica acta

, Volume 63, Issue 6, pp 511–527 | Cite as

Valency. II. Applications to molecules with first-row atoms

  • M. S. Gopinathan
  • Karl Jug
Original Investigations


A quantum chemical definition of valency proposed in Part I is used to calculate the valency of carbon, nitrogen, oxygen, lithium, beryllium and boron in a number of compounds with the SINDO1 method. It is demonstrated that consistency of the basis set is necessary for comparable results. The general features of valency and bonding in these molecules are discussed. The π-electron concept of free valence is generalised to sigma systems and atoms in molecules are classified as subvalent, normal or hypervalent. The relation between valency and natural hybrid occupancy is illustrated. The symmetry properties of natural hybrid orbitals are discussed by means of group theory. A preliminary attempt is made to relate covalency and covalent reactivity. Bond indices and the σ, π character of bonds are obtained by a suitable partitioning and projection of valency into bonding and antibonding contributions.

Key words

Valency of first-row atoms Free valence Bond indices Natural hybrids 


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Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • M. S. Gopinathan
    • 1
  • Karl Jug
    • 1
  1. 1.Theoretische ChemieUniversität HannoverHannoverFederal Republic of Germany

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