Additional x-ray structure studies on low chalcocite generally confirm the previously reported structure but show that either disorder is present or the true space group is not P2(1)/c but Pc, four of the 96 copper atoms in the monoclinic unit cell taking on twofold (linear) coordination. The crystal structure of djurleite has been solved in space group P2(1)/n, the monoclinic cell having parameters a = 26.897, b = 15.745, and c = 13.565 angstroms; beta = 90.13 degrees ; and a content of 248 copper and 128 sulfur atoms. Of the 62 different copper atoms in the structure, 52 are in threefold, triangular coordination with sulfur, nine in tetrahedral, and one in linear coordination.