Potassium persulfate

The sodium and potassium salts are very similar. In the potassium salt, the O-O distance is 1.495Å. The individual sulfate groups are tetrahedral, with three short S-O distances near 1.43 and one long S-O bond at 1.65Å. ==Preparation==

Potassium persulfate can be prepared by electrolysis of a cold solution potassium bisulfate in sulfuric acid at a high current density. : 2 KHSO4 → K2S2O8 + H2 It can also be prepared by adding potassium bisulfate (KHSO4) to a solution of the more soluble salt ammonium peroxydisulfate (NH4)2S2O8. Several million kilograms of the ammonium, sodium, and potassium salts of peroxydisulfate are produced annually. ==Uses==

This salt is used to initiate polymerization of various alkenes leading to commercially important polymers such as styrene-butadiene rubber and polytetrafluoroethylene and related materials. In solution, the dianion dissociates to give radicals: :[O3SO-OSO3]2− 2 [SO4]•− It is used in organic chemistry as an oxidizing agent, for instance in the Elbs persulfate oxidation of phenols and the Boyland–Sims oxidation of anilines. As a strong yet stable bleaching agent it also finds use in various hair bleaches and lighteners. Such brief and non-continuous use is normally hazard free, however prolonged contact can cause skin irritation. It has been used as an improving agent for flour with the E number E922, although it is no longer approved for this use within the EU. ==Precautions==

The salt is a strong oxidant and is incompatible with organic compounds. Prolonged skin contact can result in irritation. ==References==