Bridging η 2 ‐BO in B 2 (BO) 3 − and B 3 (BO) 3 − Clusters: Boronyl Analogs of Boranes

Anion photoelectron spectroscopy and theoretical calculations are combined to probe the structures and chemical bonding of two boron‐rich oxide clusters, B 5 O 3 − and B 6 O 3 − , which are shown to be appropriately formulated as B 2 (BO) 3 − and B 3 (BO) 3 − , respectively. The anion clusters are found to each possess a bridging η 2 ‐BO group, as well as two terminal BO groups and are analogs of B 2 H 3 − and B 3 H 3 − . This finding advances the boronyl chemistry and helps establish the isolobal analogy between boron‐rich oxide clusters and boranes.