Thermochemical database for modelling aqueous solution chemistry, including more than 230,000 critically-assessed equilibrium constants and enthalpies for about 70,000 reactions.

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 selected fluid systems.

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.

Interactive periodic table. Clicking on an element brings up a list of general properties and data, and information on its discovery, history, uses, geologic occurrence and abundance, compounds, and chemical isolation.