Gas-Phase Preparation of 1-Germavinylidene (H₂CGe; X¹A₁), the Isovalent Counterpart of Vinylidene (H₂CC; X¹A₁), via Non-adiabatic Dynamics through the Elementary Reaction of Ground State Atomic Carbon (C; ³P) with Germane (GeH₄; X¹A₁)

1-Germavinylidene (H₂CGe; X¹A₁), the germanium analogue of vinylidene (H₂CC; X¹A₁), was prepared via a directed gas-phase synthesis through the bimolecular reaction of ground state atomic carbon (C; ³P) with germane (GeH₄; X¹A₁) under single-collision conditions. The reaction commences with the barrierless insertion of carbon into the Ge-H bond followed by intersystem crossing from the triplet to singlet surface and migration of atomic hydrogen to germylene (H₂GeCH₂), which predominantly decomposes via molecular hydrogen loss to 1-germavinylidene (H₂CGe; X¹A₁). Therefore, the replacement of a single carbon atom in the acetylene-vinylidene system by germanium critically impacts the chemical bonding, molecular structure, and thermodynamic stability of the carbene-type structures favoring 1-germavinylidene (H₂CGe) over germyne (HGeCH) by 160 kJ mol^-1. Hence, the carbon-germane system represents a benchmark in the exploration of the chemistries of main group 14 elements with germanium-bearing systems showing few similarities with the isovalent carbon system.