A curative composition includes a tetraalkylphosphonium or tetraalkylammonium cation and an anion represented by Formula (Rf)3CO−, wherein each Rf is independently perfluoroalkyl having up to 12 carbon atoms. A fluoropolymer composition includes the curative composition and a fluoropolymer. The fluoropolymer can be an amorphous, curable fluoropolymer with nitrogen-containing cure sites. Shaped articles including the fluoropolymer, a method of making a fluoroelastomer article, and a method of making the curative composition are also described.