Tetrahedral complexes valence shell electron pair repulsion

The observed variations in the N—C bond distances and < C3—N—C angles are not in agreement with the valence-shell electron-pair repulsion model. This predicts that partial removal of the lone-pair electrons on the nitrogen atom would lead to a shortening of the N—C bonds. It would further predict that < C3—N—C should be greater than tetrahedral in the free donor and decrease on complex formation. 

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