Nonequilibrium growth of crystals has revealed an astonishing variety of structures, resulting from the interplay of relevant factors such as atomic mobility, thermal effect, dynamic heterogeneity, etc. In preparing thin films of the thermally unstable copper nitride Cu3N, growth proceeds with simultaneous nitrogen reemission, which both bestows a preferred, Cu-terminated I I I I I facet on the Cu3N crystallites and limits their size to about 45 nm. The authors observed an orogenic movement Of Cu3N nanocrystals via glide along the {111} planes, resulting in a hollow, relief morphology primarily of round caps and later of mesoscale rosettes which often demonstrate a fivefold symmetry at the center. The area expansion in the thin film by a few percent is sustained through the rearrangement of nanocrystals into ragged steps and terraces, while the ongoing fast growth prevents the relief features from cracking. The results bear broad significance for the film growth of thermally unstable materials. (c) 2007 American Vacuum Society.