The term persulfate refers to ions or compounds with more oxygen than normal sulfates.
These do not have sulfur in a different oxidation state; rather, they contain peroxide units, where two oxygens take the place of one in a normal sulfate; the oxygen atoms are in oxidation state -1.
The main forms are peroxomonosulfates and peroxodisulfates.
Ammonium persulfate (NH4)2S2O8 has been prepared by H. Marshall[1] by the method used for the preparation of Potassium persulfate. It is very soluble in cold water, a large fall of temperature accompanying solution. It is a very strong oxidizing agent and a radical initiator. It is used to etch copper on printed circuit boards as an alternative to ferric chloride solution[citation needed] It is also used along with tetramethylethylenediamine to catalyze the polymerization of acrylamide in making a polyacrylamide gel.
Potassium persulphate (K2S2O8) is a chemical compound. It is a food additive and it is used in organic chemistry as an oxidizing agent for instance in the Elbs persulfate oxidation.
Conditions/substances to avoid are: heat, flames, ignition sources, powdered metals, phosphorus, hydrides, organic matter, halogens, acids and alkalis.
It is used as a bleach, both standalone (particularly in hair cosmetics) and as a detergent component. It is a replacement for ammonium persulfate in etching mixtures for zinc and printed circuit boards, and is used for pickling of copper and some other metals. It is a source of free radicals, making it useful as a radical initiator for emulsion polymerization reactions and for accelerated curing of low formaldehyde adhesives. It is also used as a soil conditioner and in manufacture of dyestuffs, modification of starch, bleach activator, desizing agent for oxidative desizing, etc.
Conditions/substances to avoid mixing persulfates with are: moisture, heat, flame, ignition sources, shock, friction, reducing agents, organic material, sodium peroxide, water, aluminum and powdered metals.