Enthalpy of formation for natural paulingite zeolite

Natural paulingite zeolite of the composition (K_4.48Na_0.56Ca_2.95Ba_0.87Mg_0.06)[Al_11.04Fe _0.04 ³⁺ Si_30.49O₈₄] · 35.25H₂O (Vinariská Hora, Czechia) was studied calorimetrically on a high-temperature Tian-Calvet microcalorimeter. Enthalpies of formation from oxides (?1969 ± 128 kJ/mol) and elements (?52393 ± 132 kJ/mol) were determined for this mineral by melt dissolution calorimetry. The obtained experimental results and the literature data were used to calculate the Gibbs free energy of formation from elements.