In the laser ablation–molecular beam (LAMB) method, laser ablation of metal substrates in vacuum is utilized for the formation of novel organometallic and metal complex compounds containing monopositive metal ions. Mixed‐metal binuclear carbonyl ions [MCr(CO)n]+, n=0–6, are prepared in the gas phase by the reaction of laser‐ablated metal ions (M+) and Cr(CO)6 in the molecular beam injected nearby. The relative abundance of these ions, for M=transition metals, can essentially be explained by the M+–Cr bond dissociation energies. Results of density functional calculation show that this is essentially valid. © 1997 John Wiley & Sons, Ltd.