A DTA and DSC study was made of the thermal dehydration and decomposition of Mg(IO3)2·4H2O and Mg(IO3)2·4D2O. The data obtained show that the dehydration takes place in one stage. The ΔHdeho
obtained were used to calculate ΔHfo
, and comparisons were made with the literature data. It was confirmed that the thermal decomposition passes through an intermediate
Mg5(IO6)2, which is unstable and immediately decomposes to MgO. An isotope effect is observed in both DTA and DSC curves. Thermogravimetric
data on Mg(IO3)2·10H2O are also presented.