Infrared photodissociation spectroscopy of trigonal bipyramidal 19-electron Ni(CO)5+ cation

► Ni(CO)n+ (n = 4-7) complexes are studied with IR photodissociation spectroscopy. ► Ni(CO)5+ is characterized as a fivefold coordinated trigonal bipyramidal complex. ► Ni(CO)5+ is a homoleptic carbonyl complex having 19 valence electrons.