Anion photoelectron spectroscopy and quantum chemical calculations of bimetallic niobium–aluminum clusters NbAln−/0 (n = 3–12): identification of a half-encapsulated symmetric structure for NbAl12−

NbAl 12 − has a C 3v symmetric half-encapsulated structure, which can be viewed as a NbAl 6 regular hexagon over a bowl-shaped Al 6 structure.