At the same conditions of pH (3.5 to 5.0), temperature (23 °C), and concentration (1 to 10 × 10−3 M), ZnS2O4 is more stable in aqueous solution than Na2S2O4, and the rate of decomposition is much less sensitive to [H+]. At pH 4.5 and 5.0, the decomposition of the Zn salt is essentially linear, whereas the Na2S2O4 decomposes slowly at first, during an induction period, and then rapidly by an autocatalytic reaction. The rate of decomposition of dilute aqueous Na2S2O4 at pH about 4 is slowed greatly by the addition of small quantities of In3+, Cd2+, or Zn2+. The effect of the stabilizing ions is attributed to anti-catalytic action.