A method of making alpha ,omega-diiodoperfluoroalkanes includes combining: diatomic iodine, at least one perfluoroalkylene oxide represented by the formula wherein Rf represents a perfluoroalkyl group; and at least one of: a) a first metallic compound comprising nickel, and a second metallic compound comprising molybdenum that is compositionally different from the first metallic compound; or b) a metallic alloy comprising from 50 to 70 percent by weight of nickel and from 20 to 40 percent by weight of molybdenum, based on the total weight of the metallic alloy, thereby producing at least one product represented by the formula I(CF2)nI, wherein n independently represents an integer in the range of from 1 to 11. The total weight of the at least one product wherein n is 3 or greater exceeds the total weight of the at least one product wherein n is 1 or 2 by a factor of at least 4.