Thermal decomposition temperatures of metal sulfates

The thermal decomposition of sixteen metal sulfates was studied by thermogravimetry at heating rates of 2 and 5°C min−1 in flowing air and high-purity nitrogen. Their decomposition behaviors, especially the initial decomposition temperatures, were examined with relation to the thermodynamic functions for decomposition. Of the factors possibly influencing the decomposition temperature, the equilibrium SO3 pressures over the sulfates were evaluated: the equilibrium pressures at the initial temperatures for sulfates of metals, of which the oxidation state was unchanged during decomposition, were nearly equal to 1×10−4 atm at 2°C min−1 in flowing nitrogen.