A photoelectron spectroscopic and theoretical study of B16- and B16(2-): an all-boron naphthalene.

The structure and chemical bonding of B16- were studied using ab initio calculations and photoelectron spectroscopy. Its global minimum is found to be a quasi-planar and elongated structure (C2h). Addition of an electron to B16- resulted in a perfectly planar and closed shell B16(2-) (D2h), which is shown to possess 10 pi electrons with a pi-bonding pattern similar to that of naphthalene and can thus be considered as an "all-boron naphthalene", a new member in the growing family of hydrocarbon analogues of boron clusters.