First detection of the silylgermylene (H3SiGeH) and D4-silylgermylene (D3SiGeD) molecules in low temperature silane-germane ices

► Silylgermylene (H3SiGeH(X1A′)) was detected via infrared spectroscopy. ► The silylgermylene was characterized using the ν5 fundamental at 860 cm−1. ► Kinetic studies suggest H3SiGeH to form via unimolecular decomposition of H3SiGeH3.