Calorimetric studies of natural talc: Enthalpy of dehydroxylation

The standard dehydroxylation enthalpy of natural talc Mg₃Si₄O₁₀](OH)₂ (87.8 ± 9.0 kJ/mol at 298.15 K) and the enthalpy of formation of dehydrated talc from the elements (Δ_f H _el^o (298.15 K) = −5527.0 ± 9.0 kJ/mol) were determined for the first time using Hess’s law, based on the total values of the enthalpy increments in heating a sample from room temperature to 973 K and the enthalpies of dissolution at 973 K for dehydrated talc measured in this work and those previously determined for talc and corresponding oxides.