the following tables percentages are in weight percent based on the total weight of the aci composition iodide salts a h designate phenyltrimethylammonium iodide a ethyl triphenylphosphonium iodide b lithium iodide c tetrabutylammonium iodide d tetraethylammonium iodide e tetrapropylammonium iodide f tetramethylammonium iodide g and ammonium iodide h in tables 1 3 and 4 the iodide salt is present in an amount of one percent by weight in table 2 the iodide salt is present in an amount of two percent by weight in addition to any performance benefits that the inclusion of an iodide salt may provide in an inhibitor formulation the stability of the acis listed above is a critical factor in determining if an aci formulation is successful because acid corrosion inhibitors contain complex mixtures of several compounds all in a balanced stable formula the addition of any particular iodide compound could disrupt this stability by causing precipitation or separation of the aci components or perhaps decreased aci performance versus the non iodide containing aci the stability of representative corrosion inhibitor compositions of the invention is shown in tables 5 and 6 as table 5 shows representative iodide salts used in a 1 percent by weight concentration were soluble in the aci formulations and showed no precipitation after 72 hours except for the aci labeled a 7 containing tetramethylammonium iodide which would not initially dissolve in the inhibitor formulation when the amount of phenyltrimethylammonium iodide ethyl triphenylphosphonium iodide ammonium iodide tetraethylammonium iodide and tetrapropylammonium iodide are doubled the ease in which they dissolve is decreased although they all dissolve over 2 hours after 24 hours a precipitate is evident in the corrosion inhibitors formulated with ammonium iodide and tetraethylammonium iodide table 6 shows the.