One superacid shaped like an icosahedron features 
One superacid shaped like an icosahedron features a skeleton almost entirely composed of this element. The selectrides are a group of reducing agents featuring this element bonded to three sec-butyl groups, and Tthe nitrogen atom in proline binds to this element in the Corey-Bakshi-Shibata catalyst. Aryl- and vinyl- acids containing this element react with aryl- and vinyl-halides on catalytic palladium in the Suzuki reaction. Anti-Markovnikov addition is a feature of the best-known reaction featuring this element, in which an alkene is converted into an alcohol. That reaction features a namesake hydration followed by an oxidation and is catalyzed by a reactive compound consisting of this element bonded to three hydrogen atoms.  For 10 points, name this fifth element.
One superacid shaped like an icosahedron features a skeleton almost entirely composed of this element.
boron