Acquisition and evaluation of thermodynamic data for mirabilite-thenardite equilibria at 0.1 MPa

•Equilibrium constants between mirabilite and thenardite were determined.•Mass changes of solids were measured after reacted at fixed humidity–T conditions.•The stability boundary between mirabilite and thenardite was defined at 0.1MPa.•Our results were used to evaluate previous works and derive thermodynamic data.