[en] The reaction and topological cross sections for anti pn interactions producing 3 or 5 charged particles are measured. This is done using data from the Brookhaven National Laboratory 31-inch deuterium-filled bubble chamber. The s-channel behavior of intermediate states of the reaction anti pn → 2π⁺3π^-, in particular, the rho⁰rho⁰π^- state, are examined for possible structure at a center of mass energy of 2190 MeV. With a 90 percent confidence, no enhancement is found at a level of 0.7 mb if the width is assumed to be +-50 MeV. In addition, the complications involved in using a deuterium target as a source of neutrons are investigated using anti pn annihilations. The results indicate discrepancies with the assumption that deuterons can be used as a source of quasi-free neutrons. In this work, the double-scattering effect accounts for approximately 30 percent of the apparent anti pn annihilation events. An examination of the properties of protons emerging from the anti pd annihilations indicates that the data can be properly described if and only if effects of double scattering are considered