Molecular manganese fluorides were studied using quantum-chemical calculations at DFT and CCSD(T) levels and experimentally by matrix-isolation techniques. They were prepared by co-deposition of IR-laser ablated elemental manganese or manganese trifluoride with F₂ in an excess of Ne, Ar, or N₂ or with neat F₂ at 5–12 K. New IR bands in the Mn–F stretching region are detected and assigned to matrix-isolated molecular MnF_x (x = 1–3).