The main finding of Haber and Weiss was that hydrogen peroxide (HO) is decomposed by a chain reaction.
The Haber–Weiss reaction chain proceeds by successive steps: (i) initiation, (ii) propagation and (iii) termination.
The chain is initiated by the Fenton reaction:
:Fe + HO → Fe + HO + HO     (step 1: initiation)
Then, the reaction chain propagates by means of two successive steps:
:HO + HO → HO + O + H        (step 2: propagation)
:O + H + HO → O + HO + HO    (step 3: propagation)
Finally, the chain is terminated when the hydroxyl radical is scavenged by a ferrous ion:
:Fe + HO + H → Fe + HO         (step 4: termination)
George showed in 1947 that, in water, step 3 cannot compete with the spontaneous disproportionation of superoxide, and proposed an improved mechanism for the disappearance of hydrogen peroxide. See  for a summary. The reactions proposed therein  are:
:Fe + HO → Fe + HO + HO    (initiation)
:Fe + HO → Fe + HO    (termination)
:HO + HO → HO + HO    (propagation)
:Fe + HO → Fe + HO    (termination)
:Fe + HO → Fe + HO + H    (termination)