Interpenetrating As20 fullerene and Ni12 icosahedra in the onion-skin [As@Ni12@As20]3- ion

The [As@Ni-12@As-20](3-) ion was prepared from As-7(3-) and Ni(COD)(2) in ethylenediamine solutions and isolated as the Bu4P+ salt (As, arsenic; Ni, nickel; COD, cyclooctadiene; Bu, butyl; P, phosphorus). The anion contains an icosahedral [Ni-12(mu(12)-As)](3-) fragment that resides at the center of an As-20 dodecahedral (fullerene) cage to give an onion-skin-like [As@Ni-12@As-20](3-) cluster with 1 h point symmetry. The icosahedron and pentagonal dodecahedron are reciprocal platonic solids, and the 32 surface atoms form a dimpled geodesic sphere composed of 60 triangular faces. In the gas phase, the [As@Ni-12@As-20](3-) ion sequentially loses all 21 As atoms to form a series of Ni12As21-x clusters where 0 less than or equal to x less than or equal to 21, inclusively.