Computational evidence for homonuclear Ge(I)Ge(I) dative bonds.

Dative bonds between identical atoms of the same formal oxidation state are formed as geometric and electronic constraints turn an otherwise lone pair into a bond. Calculations at the B3LYP/6-31+g(d,p) level supported by additional atoms in molecules (AIM) and electron localization function (ELF) analyses on selected germanium polycations are used to prove the concept. The electron density (ρ) is not equally shared between the two atoms of such a homonuclear dative bond (HDB) and the associated charge transfer results in formal charges contradicting chemical convention.