Science

This National Institute of Standards and Technology website with 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.

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

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.