2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/120472We prove that Dirichlet stereohedra for non-cubic crystallographic groups in dimension 3 cannot have more than 80 facets. The bound depends on the particular crystallographic group considered and is above 50 only on 9 of the 97 affine conjugacy classes of them. We also construct Dirichlet stereohedra with 32 and 29 facets for a hexagonal and a tetragonal group, respectively.27 pages, 18 figures, 7 tablesCombinatoricsMetric Geometry52C22; 20H15, 52B10text