Long-range reduction of CuO to Cu2O and Cu was observed by irradiating polycrystals and different planes of CuO single crystals ((110) and (020)) with 16-MeV nitrogen ions with fluence 1017 cm-2. The infrared absorption spectra show an increase in the number of hole [CuO4]5- and electronic [CuO4]7- centers. The highest density of electronic centers and reduction occur near the surfaces of the samples.