Agostic deformations based on electron delocalization in the alkyllithium-complex [{2-(Me3Si)2CLiC5H4N }2Electronic supplementary information (ESI) available: experimental and theoretical details of multipole refinements and model systems. See http://www.rsc.org/suppdata/cc/b1/b105452j/

Topological analysis of experimental and theoretical charge densities in the title complex [(2-(Me3Si)2CLiC5H4N)2] 1 reveals the nature of the agostic deformation postulated for this complex: delocalization of the Li-C bonding electrons over the entire agostic alkyl group controls the formation of an acute Li-C-Si angle and thus a sufficient electronic saturation of the electron deficient lithium atom via secondary interactions.