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

Highlights: ► 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. -- Abstract: The thermodynamically most stable GeSiH4 isomer – silylgermylene (H3SiGeH(X1A′)) – and its perdeuterated counterpart were detected for the first time via infrared spectroscopy in low temperature silane (SiH4) – germane (GeH4) and D4-silane – D4-germane ices upon irradiation with energetic electrons through the ν5 and ν3 fundamentals at 860 cm−1 and at 1309 cm−1, respectively. Our kinetic studies suggest that silylgermylene is formed via decomposition of chemically activated silylgermane (H3SiGeH3) precursors.