Chemical Book — for chemical and thermal properties, spectra, and more on a range of chemical compounds
Chemical Synthesis Database — contains substances with their synthesis references and physical properties such as melting point, boiling point and density
ChemSpider — all-in-one chemistry search engine and news blog. Maintained by the Royal Society of Chemistry
EMolecules — open-access chemistry search engine. Draw a structure, search named chemicals, or browse by category
General Chemistry Online — common compound database, chemical construction kits, guides to 1st semester general chemistry, calculators, self-guided, interactive tutorials and more to help prepare new chemistry students
KnowledgeDoor — online and tablet-friendly conversion calculators; periodic tables; tools for atomic structures, thermodynamics, nomenclature and more. An all-in-one chemistry reference and units & constants handbook for chemistry students and experts alike
Learn Chemistry — by the Royal Society of Chemistry. Learn chemistry terms and concepts through presentations, tutorials, quizzes, games and more
MatWeb — material property data. Searchable database of material data sheets. Contains data sheets for thousands of metals, plastics, ceramics, and composites
PubChem Project — one-stop chemical research database. Research bio-activities of small molecules, substance info & compound structures. By NIH, NLM (Nat’l Library of Medicine) & PubMed
SpectraSchool — by U. Leicester. Plot 1H and 13C NMR, IR, Mass and UV/Vis spectra for a range of compounds. Help you understand the principles and practice of spectroscopy and spectroscopic methods
Thermodex — by UT Austin. Index of selected thermodynamic and physical property resources
MatWeb (Material Property Data) — searchable database of material data sheets. Contains data sheets for thousands of metals, plastics, ceramics, and composites