Ammonium persulfate

Ammonium Persulfate
IUPAC name: see chemistry section Synonyms: Ammonium Peroxydisulfate; Peroxydisulfuric Acid, Diammonium Salt; Diammonium peroxydisulfate Formula: (NH4)2S2O8
Uses:	polymerization initiator, decontamination
Properties:	radical initiator, oxidizer
Hazards:	strong oxidizer, burns
Mass (g/mol): CAS #: 228.2 7727-54-0

Ammonium persulfate is a very strong oxidizer used for industrial cleaning and decontamination, as well as a strong radical initiator often used to promote polymerization reactions. Its oxidation potential, at 2.1 V, is only slightly weaker than ozone (O₃^2-, 2.2) but stronger than both hydrogen peroxide (H₂O₂, 1.8 V) and permanganate (MnO₄, 1.7V). It is also widely used in polyacrylamide gel electrophoresis (PAGE) within biochemistry labs. The persulfate radical is particularly stable relative to many other radicals, and it is often stabilized even more by the addition of tetramethylethylenediamine (TEMED).

Oxidation chemistry

When used as an oxidizing agent, the reduction of the persulfate ion occurs as indicated in equation (1).

(1) S₂O₈^2- + 2H⁺ + 2e^- $\rightarrow$ 2HSO₄^- (2.1 V)

Free radical chemistry

The persulfate ion self-decomposes into sulfate radicals, with oxidation potential 2.6 V, as indicated in equation (2).

(2) S₂O₈^2- $\rightarrow$ 2SO₄^.-