Though xanthogen formates have long been used as sulfide mineral collectors, they have been largely ignored by the research community. The flotation of chalcopyrite, chalcocite, covellite, bornite and pyrite with this class of collector has been evaluated using a variety of hydrocarbon constituent groupings, in both the xanthogen and the formate positions. In addition to being stable in acidic circuits, xanthogen formates are shown to be effective copper sulfide collectors over a broad pH range (5.0-10.5). In general, many of the nine especially synthesized xanthogen formates were found to discriminate against the flotation of pyrite. It is possible to tailor make these compounds to enhance or diminish the flotation of pyrite. (C) 2000 Elsevier Science B.V. All rights reserved.