Endohedral Ca@B38: stabilization of a B38(2-) borospherene dianion by metal encapsulation.

Based on extensive global-minimum searches and first-principles electronic structure calculations, we present the viability of an endohedral metalloborospherene Cs Ca@B38 () which contains a Cs B38(2-) () dianion composed of interwoven boron double chains with a σ + π double delocalization bonding pattern, extending the Bn(q) (q = n - 40) borospherene family from n = 39-42 to n = 38. Transition metal endohedral complexes Cs M@B38 (M = Sc, Y, Ti) (, , ) based on Cs B38(2-) () are also predicted.