closo-borane

The term "closo-borane" refers to a specific structural classification within the broader family of boranes, which are inorganic compounds composed of boron and hydrogen. In borane nomenclature, "closo-" (derived from the Latin word for "cage") describes deltahedral structures where the boron atoms form a complete, closed cage. These structures are characterized by n boron atoms occupying n vertices of a polyhedron.1

Boranes themselves were first systematically studied by Alfred Stock and are known for their unique bonding, often involving multicenter bonds where electron pairs are shared among three or more atoms. This electron-deficient nature distinguishes them from carbon hydrides. While simpler boranes can be reactive, more complex structures like closo-boranes tend to be more stable. Carboranes are related compounds that incorporate carbon atoms into these boron-hydrogen cages.12