Strengths of Bonds from Metal Ions to Ligands

Strengths of Bonds from Metal Ions to Ligands 

In analyzing inorganic structures, Brown (1978) extended the ball-and-stick valence models of organic structures to inorganic structures, 

if a magnesium ion binds six oxygen atoms, the strength of each metal ligand interaction is 2/6 = 0.33. If the cation is sodium, with the same coordination number, the bond strength is lower, 0.17. The above equation can be rewritten as 

Valence (charge) of metal ion = 2aii atoms (bond valence) 

Analyses of metal coordination and the bond strengths started with the publication by Pauling (1929) of an article entitled The Principles Determining the Structure of Complex Ionic Crystals. In this article Pauling defined the bond strength as listed above. Later, it became clear from measurements of bond lengths by X-ray crystallographic analyses that 

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VII. Strengths of Bonds from Metal Ions to Ligands... 

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