This very intriguing observation need additional explanation. The first question arises about the structure of both hydride complexes and the energy of their formation. Especially interesting are factors that determine the possibility of the formation of the σ-bond complex and its transformation to the oxidation addition product. The next question is at which point the hydride and germyl ligands are transferred to the olefin bond coordinated to metal norbornadiene. The answer to these question are very important in investigations of the mechanism of hydrogermylation reaction and the analogous hydrosilylation and stannylation reaction of norbornadiene in the presence of photochemically activated molybdenum and tungsten carbonyl complexes