Chalcocite Tomeoka K, Ohmasa M American Mineralogist 67 (1982) 360-372 The modulated structure of cubic Cu9BiS6 the alpha phase _database_code_amcsd 0000864 5.563 5.563 5.563 90 90 90 Fm3m atom x y z occ Biso Bi .5 .5 .5 .138 4.86 Cu1 .2787 .2787 .2787 .109 1.59 Cu2 .3333 .3333 .3333 .059 2.47 S 0 0 0 1.45