Joint Expert Speciation System - Thermochemical database for modelling aqueous solution chemistry, including more than 230,000 critically-assessed equilibrium constants and enthalpies for about 70,000 reactions. - http://jess.murdoch.edu.au
Thermodynamic Database - Molar heat capacity, entropy, and standard enthalpy of formation values for selected elements and compounds. Data are given at 100 degree intervals from 200 to 3000 K, and also summarized for all species at 298 K. - http://www.me.berkeley.edu/gri-mech/data/thermo_table.html
NIST Chemistry WebBook - This National Institute of Standards and Technology website provides thermochemical, thermophysical, and ion energetics data. Information and data on gas-phase ion, organic, and organometallic thermochemistry, as well as thermophysical properties of selec - http://webbook.nist.gov/chemistry/