Thermodynamic studies of zeolites: clinoptilolite

Calorimetric studies are described of a carefully characterized specimen of clinoptilolite (Malheur County, Oregon, U.S.A.) of composition: S r 0.036 M g 0.124 C a 0.761 M n 0.002 B a 0.062 K 0.543 N a 0.954 A l 3.450 F e 0.017 S i 14.533 O 36.000 ⋅ 10.922 H 2 O . Values are reported of the standard molar enthalpies of formation Δ f H o m at 298.15 K and of the standard molar enthalpy increments { H o m ( T ) − H o m (298.15 K)} for both clinoptilolite and dehydrated clinoptilolite, as well as the low-temperature molar heat capacity C o p ,m and, by derivation, the standard molar entropy increment { S o m ( T ) − S o m (0)} for clinoptilolite alone. The conventional thermodynamic properties have been calculated for both compounds.