B5H7

B5H7 (pentaborane) is a boron hydride compound belonging to the class of boranes—molecular ceramics with strong B-H bonding and high energy density. This material is primarily of research and historical interest rather than mainstream engineering use; it has been investigated as a high-energy rocket propellant and in synthetic chemistry as a reducing agent and precursor for boron-containing materials. Pentaborane is notable for its thermal instability and extreme reactivity, making it hazardous to handle, which has limited its adoption compared to conventional propellants and chemical reagents.