Nickel carbonyl clusters in molecular beams: a reinterpretation of the results which gives circumstantial evidence for a face-capping cluster-growth sequence

Abstract

Nickel cluster ions, size selected by quadrupole mass spectrometry, have been reacted with carbon monoxide to yield in the gas phase nickel carbonyl clusters of the type Ni{sub n}(CO){sub k}{sup +} and Ni{sub n}C(CO){sub l}{sup +}, where n ranges from 1 to 13 and k and l vary as a function of cluster size n. Fayet et al. have interpreted these results using EHMO calculations on bare nickel clusters previously reported by Lauher. A reinterpretation of these results in terms of the polyhedral skeletal electron pair theory not only provides a more complete account of the stoichiometries of these clusters but also provides strong circumstantial evidence for a face-capping growth sequence based on a pentagonal bipyramidal Ni7 cluster.