Endohedral charge-transfer complex Ca@B37-: stabilization of a B373- borospherene trianion by metal-encapsulationt

Based on extensive first-principles theory calculations, we present the possibility of an endohedral charge-transfer complex, C-s Ca@B-37(-) (I), which contains a 3D aromatic fullerene-like Cs B-37(3-) (II) trianion composed of interwoven boron double chains with twelve delocalized multicenter pi bonds (12 mc-2e pi, m = 5, 6) over a a skeleton, completing the B-n(q) borospherene family (q = n - 40) in the size range of n = 36-42.