Editor's Note: This growing directory is manually maintained and automatically tested for broken links once a month. Links which appear broken for three or more consecutive months are deleted.

Should there be anything wrong with an entry, let me know and I will be glad to correct it.
Note: an entry can appear in several categories.

INSTITUTIONS, Associations and Groups

For a more generic Directory, see the Stan's links to Science Institutions.

• International:
• AOAC International. Analytical instrumentation and methods.
• CAS. Chemical Abstracts Services, a division of ACS.
• CODATA Committee on Data for Science and Technology.
• IUPAC. International Union for Pure and Applied Chemistry.
• Nobel Prize Organization.
• Terena. Trans-European Research and Education Networking Association.
• The Wired Chemist. Chemistry, Mineralogy, Environmental chemistry and NMR.
• The Wolf Foundation. Awards the Wolf Prizes.
• University Chemistry Departments. A worldwide list.
  Not very complete, but some Countries are well covered.
• WATOC. World Association of Theoretical and Computational Chemists.
• Europe:
• EuCheMS. European Association for Chemical and Molecular Sciences.
• FEBS. Federation of European Biochemical Sciences.
• RSC. Royal Society of Chemistry.
• USA:
• ACS. American Chemical Society.
• AIChE. The American Institute of Chemical Engineers.
• American Chemistry, the roof for ACC, the American Chemistry Council.
• CCC, the Center for Computational Chemistry at University of Giorgia.
• CCPS. Center for Chemical Process Safety.
  They have a lot of free documentaion on chemical hazards and chemical engineering safety aspects.
• Chemistry and Biochemistry Departments in the US. Complete list.
• EPA. Environmental Protection Agency.
• FDA. US Food and Drug Administration.
• Elsewhere:

JOURNALS, e-Zines, Libraries and Blogs

• Chemical & Engineering News. An ACS journal with free on-line content.
• Chromatography Online. A free online Magazine.
• Directory of NMR Journals & e-Zines managed by Stan Sykora.
• HYLE, International Journal for Philosophy of Chemistry. Open access.
• JCE Online, the Journal of Chemical Education.
• JCTC, Journal of Chemical Theory and Computation.
• Open Access Chemistry Journals. Last count: 82.
• Spectroscopy Asia. Similar to Spectroscopy Europe.
• Spectroscopy Europe. A free online Magazine.
• Spectroscopy Letters
• e-Zines and Portals:
• ChemWeb. A nice e-Zine for all chemists.
• Organic Chemistry Portal and weekly Organic Chemistry Highlights.
• Spectroscopy Now. A comprehensive spectroscopy portal.
• Blogs:

ENCYCLOPEDIAs, Dictionaries and Wikis

• Chemistry Thesaurus. Free.
• DiracDelta, a Science & Engineering Encyclopedia with a lot of Chemistry.
• Wikis:
• Jmol Wiki. Molecular visualization.
• Open Babel project. The Open Source Chemistry Toolbox.

Mostly free DATABASES and Directories

• Affin DB, affinity database for protein-ligand complexes at University of Marburg, Germany.
• Binding DB, structure search over 24,000 Ki & IC50 measurements from over 12,000 molecules.
• BioCyc, data on enzyme-related compounds (substrates, products, inhibitors, activators).
• Biological Pathways Database under C@ROL at TORUS, University of Erlangen, Germany.
• BRENDA, The Comprehensive Enzyme Information System
  at Braunschweig Technical University (Germany).
• CAS, Chemical Abstracts Services, a division of ACS.
• ChEBI, Chemical Entities of Biological Interest,
  a free dictionary of molecular entities focused on small chemical compounds.
• ChemBank. Over 40,000 biological assays of small molecules at Harvard's ICCB.
• ChemDB, a chemical database at UC Irvine. Includes many software applets.
• ChemDex. Huge chemistry directory at Uni Sheffield (by Mark Winters).
• ChemExper, a chemical directory matching compounds with suppliers.
• Chemical Structure Lookup Service (CSLS) aggregates several chemistry databases.
• Chemistry Safety Information from Oxford University. Important!
• Chemistry Thesaurus. Just what it says.
• ChemMine, UC Riverside compound mining database that facilitates screening of drugs, agrochemicals, and chemical genomics.
• ChemSpider of the Royal Society of Chemistry. Ex ChemRefer. A huge structure-centric service.
• ChemSynthesis. Synthesis references and properties for >40000 compunds.
• CODATA. Committee on Data for Science and Technology.
• Compendium of Pesticide Common Names.
• Computational Chemistry Comparison and Benchmark Database (CCC-BDB).
  Experimental and computational thermochemical data for a set of 788 gas-phase atoms/molecules.
• Constants of Physics and Mathematics.
• DrugBank. Detailed information on nearly 4800 drugs.
• eMolecules. Information and suppliers for over 7 million compounds!
• Genome Gateway. Genomics links, references, data, ....
• HMDB - Human Metabolome Database by D.S.Wishart et al.
• IUPAC Nomenclature. The official naming conventions.
• IUPAC-NIST Solubility Database.
  Search by name or CAS number through over 67,000 measurements.
• KEGG: Kyoto Encyclopedia of Genes and Genomes.
• National Institute of Allergy and Infectious Diseases Database (NIAID).
  Hundreds of thousands of compounds related to HIV, TB and Opportunistic Infection.
• National Toxicology Program of the Department of Health and Human Services.
• NIST Chemical Kinetics Database for thermal gas-phase chemical reactions.
• NIST Chemistry Webbook. All kinds of chemical data.
• NMRShiftDB, a SourceForge open project having as its object a free
  web database for chemical structures and their nuclear magnetic resonance data. See also.
• Organic Chemistry Info collected by J.H.Reich (Uni Wisconsin). Excellent.
• Organic Syntheses cookbook. Check System Requirements and Plugin Downloads.
• PDB, the Protein Data Bank, lists structures of proteins, nucleic acids, and complex assemblies.
• PDB bind, a collection of binding affinity data (Kd, Ki, and IC50) for the protein-ligand complexes in the PDB.
• PDSP Ki Database of the NIMH psychactive drug screening program.
• PubChem project at NCBI provides info on bio-activities of small molecules. The granddaddy of all free chemistry databases. Search over 8 million compounds by a variety of criteria. See also.
• SciStore chemical databases at CambridgeSoft.
• SI Units and Prefixes, a database useful to everybody.
• SI Dimensions of Physical Quantities. Over 200 quantities in 21 categories.
• SDBS, a database of organic compounds spectra at AIST (Japan).
• SOLV-DB, Solvents Database at NCMS.
• Web Reactions cookbook. Structure search organic reactions in four databases
  containing a total of over 391,000 reactions.
• ZINC, a chemical database of commercially-available compounds for virtual screening at UCSF.
• Link Directories:
• BUBL Link. An amazing collection of chemical links, each with a brief description.
• Chemdex. Huge chemistry Directory at Uni Sheffield (by Mark Winters).
• Chemical Register. Manual compilation of chemical suppliers.
  Includes new projects, free magazines, jobs, news and events.
• Chemistry links at Le Moyne College. Brief but nice selection.
• Martindale's Chemistry Center. Amazing.
• Martindale's Materials Science Center. Amazing.
• MIT Chemistry related sites and links.
• NMR, ESR and NQR Links. A huge, manually managed Magnetic Resonance Directory.
• Philosophy and History of Chemistry links on HYLE.
• Process Register. A large Process Industry Supplier Directory.
• R&D Chemicals. A Directory of Companies.

Lists of BOOKs, Courses and other References

• Chemistry Books, a list maintained by Stan Sykora.
• Free online Chemistry Texts, a list maintained by Stan Sykora.
• Chemistry books on eKnigu in PDF and DjVu fomats. Hundreds of items.
• FreeScience directory of free, online chemistry books.
  Very valuable resource, thought it counts as books also courses and scripta.
• Open source Chemistry Textbooks at Textbook Revolution.
• MIT Open Courses in Chemical Engineering.
• MIT Open Courses in Chemistry.
• MIT Open Courses in Materials Science and Engineering.
• Scribd directory of free, online chemistry books.
• Lists of references (send me a link to your list of publications):
• Papers by Geoffrey Blake at al. Spectroscopy in Chemistry and Cosmochemistry.
  Also included are the theses of the present and past member's of Blake's group.
• 20-th Century Chemical Instrumentation collected by Carsten Reinhardt.
• Papers by Masaru Kuno at al. Nano-chemistry.

NOBEL Prizes and Pioneers

• Nobel Prizes in Chemistry. See also the complete list.

HISTORY and Milestones

• Ava Helen and Linus Pauling Papers at Oregon State University.
• Chemistry Related Antique Optical Instruments . A collection by Allan Wissner.
• History of Chemistry directory, including also history of science in general.
• History of Chemistry on the Chymist (David Katz).
• History of Chemical Engineering.
• HYLE, International Journal for Philosophy of Chemistry. Open access.
• Named Things in Chemistry & Physics by John Andraos.
• The History of Green Chemistry and Processes, a nice article on ThomasNet.
• Milestones:

EDUCATION and Fun

• A list of free online chemistry books, courses and theses
• About.com: Chemistry. For both students and teachers.
• AceOrganicChem.com resources for students.
• Applied Chemical Kinetics course by Mark.T.Swihart (CE561, Uni Buffalo). Well organized.
• Centre for Bioscience of the Higher Education Academy.
• Chem 1 Virtual Textbook by Stephen Lower. Excellent.
• Chemistry Hypermedia Project. Nice but abandoned.
• Chemistry Safety Information from Oxford University.
• Chemistry Tutorials at Sheffield Hallam University (UK). Introductory primers.
• ChemTutor. Undergraduate primers on many topics.
• Environmental Chemistry lecture notes (ENV440, Northern Arizona University).
• Home page of David A.Katz. Excellent
  Some sections: The General Chemistry Survival Manual, History of Chemistry, The Complete Chymical Demonstrator, etc.
• Home page of Mark Winters. Do not miss this one!
  Mark is the Author of Web Elements, Chemdex, Chemputer and Orbitron.
• Khan Academy, open-source chemistry videos and lessons. Amazing!. See also.
• MIT Open Courses in Chemical Engineering. Free.
• MIT Open Courses in Chemistry. Free.
• MIT Open Courses in Materials Science and Engineering. Free.
• Named Things in Chemistry & Physics by John Andraos.
• Orbitron. Nice visualization of atomic and moleculear orbitals by Mark Winters.
• TeachSpin. Small instruments for teaching Science.
• TelAtomic. Small instruments for teaching Science.
• Teaching and Research Web Site of David W.Brooks.
  For high-school chemistry teachers and students. Crammed with useful content.
• The Science of Spectroscopy for the advanced.
• Thermodynamics, lecture notes by Zoltan S.Spakovszky (MIT). Exhaustive and excellent.
• Virtual Textbook of Organic Chemistry by William Reusch. Excellent.
• Fun:
• 1001 things to do with Liquid Nitrogen which you should NOT do!
• Bizarre Stuff. You can make it in your kitchen.
• ChemComics Project of J.P.Selegue and F.JamesHoller. The best periodic table ever.
• Chemist's Haiku. You can add your own.
• Chymist.com site of David A.Katz. Combines education with fun.
• JetPunk periodic table quizz. Try it (I have failed).
• Reactive reports. No comment :-)
• Science poetry & fun corner in Stan's and Lucia's Log Cabin.
• Silly molecules. You must see this to believe it.
• Science Songs by Greg Crowther et al. See also his science songs links.
• The ultimate pill. Farmaceutical.
• Virtual Chembook by Charles E.Ophardt.

INFO... sites, generic articles and special topics

• Chemical Markup Language (CML), an open project on SourceFORGE.net.
• File formats and coordinates for molecular encoding on Jmol Wiki.
• IUPAC Nomenclature. Official naming conventions.
• Named reactions directory.
• Virtual Academy of Organic Semiconductors at Uni Lintz, Austria.
• Articles
• A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry by Pablo Echenique and J.L.Alonso.
• A Statistical Mechanical Approach to Combinatorial Chemistry by Michael W.Deem.
• Better Designs for Optimization of Organic Processes
  by Edward Vawter of QD Information Services.
• Chemicals Articles on ThomasNet.
• Hacking PubChem: Direct Access with FTP by Rich Apodaca.
• Quantum Monte Carlo methods for the solution of the Schroedinger equation for molecular systems by Alán Aspuru-Guzik and William A.Lester Jr.
• Water properties. A review by Martin Chaplain. Fabulous.
• What Should Every Chemist Know About Patents, a PDF article (1.12 MB).
• Quantum Chemistry
• The ABC of DFT, a free book by Kieron Burke and friends at UCIrvine.
  See also their other resources.

PERIODIC Tables and related matters

• ChemComics Project of J.P.Selegue and F.JamesHoller. The best periodic table ever. Fun.
• Chemical Elements periodic table. Interactive.
• Chemicool Periodic Table.
• David's Whizzy Periodic Table shows electron structure of elements (dynamic Java applet).
• Elements Database Periodic Table with description of all elements and a Periodic Table Quiz.
• JetPunk periodic table quizz. Try it (I have failed it)!
• Los Alamos periodic table.
• Multi-lingual, strongly interactive periodic table by Ivan Noels (Mokeur).
• Multi-lingual periodic table from Croatia. Excellent and serious.
• NMR Periodic table at NHMFL (Spectroscopy).
• NMR Periodic table at TAMU.
• NMR Periodic table from Numare Spectralab.
• Periodic Table at Knovel. Licensed from and customized by Touchspin Chemistry.
• Periodic Table at Particle Data Group. Absolutely superb.
• Periodic Table by Albert Tarantola (Janet form).
• Periodic Table by Roman Kovalenko. Nice.
• Periodic Table from Chemical & Engineering News. 80th anniversary issue.
• Periodic Table from Monachos Mechanical Engineering.
• Periodic Table of the chemical elements quantum mechanics consistent by Bernard Schaeffer.
• Periodic Table Quilt at Simon Frazer University.
• Prospects for Further Considerable Extension of the Periodic Table, an article
  by Glenn T. Seaborg, Journal of Chemical Education, Vol.46, Number 10, p.626, 1969.
• The Elements, a famous song by Tom Lehrer.
• Touchspin Periodic Table. Amazing.
• Visionlaerning description of the Periodic Table.
• Web Elements by Mark Winters (at Uni Sheffield). Excellent.
• Wikipedia periodic table.

SOFTWARE

• Free, open-source and/or very low-cost:
• A large Directory of free NMR Software maintained by Stan Sykora.
• ACD/ChemSketch from ACD Labs. Free.
• Biochemical software from the National Center for Biomolecular Research in Brno, Czech Republic. Free for non-commercial uses. TRITON, CICADA, EEM and ABEEM SOLVER, MOLE.
• Chemistry Calculator spreadsheet for students.
• ChemPen. 3D molecules for $99. C13 shift calculations.
• Chempute Software. See the Free Engineering Software table.
• Chemputer. On-line chemistry computer by Mark Winters.
• ChemScribe. Word processing tool for organic chemist.
• Crystal designer. Free limited version.
• Excel simulation programs from Chemistry Hypermedia Project.
• MDL/Symyx free software (just register). Applications and plug-ins.
  ISIS with popular ISIS Draw, MDL Chime, and much more.
• JCE Online software list (with many downloads).
• JMol open-source Java molecular viewer (3D, animated, ...).
• Open Babel SourceForge project and Open Babel wiki. An open source Chemistry toolbox.
  File formats conversion and much more. Fantastic: get involved!
• OSIRIS molecular properties prediction (MedChem). Web based.
• Protein Data Bank.
• TRITON, a graphical tool for computational aided protein engineering.
• YASARA. Yet Another Scientific Artificial Reality Application. Free molecular modelling.
• Commercial software:
• A complete Directory of NMR software Companies maintained by Stan Sykora.
• Chempute Software has tons of chemical engineering software.
• Online LIMS, the home of Laboratory Information Management Systems.
• Q-Chem, a quantum chemistry ab-initio computations package.
• Soluzioni Informatiche. Commercial chemical and biochemical software.
• CambridgeSoft. Home of ChemDraw, ChemOffice, BioDraw, BioOffice, and combinations.
• Mestrelab Research. Top NMR and MS data evaluation software.
• The Unscrambler from CAMO is all you need for multivariate analysis. 30 days demo.
• Upstream Solutions. Software tools to generate information from chemical data.

Properties of chemical compounds and materials

• Aerogel. The best thermal insulator and lightest construction material.
• ChemExper, a Chemical Directory matching compounds with suppliers.
• eMolecules. Information and suppliers for over 7 million compounds.
• NIST Chemistry Webbook (chemical data).

Info DIRECTORIES and SUPPLIERS of materials, instruments and tools

• Directories:
• Alpha Aesar. Research chemicals, metals and materials worldwide.
• Chemical Register. Manual compilation of chemical suppliers.
  Includes new projects, free magazines, jobs, news and events.
• Chemical Suppliers. Directory of Companies with products/services for drug discovery industry.
• eMolecules. Information and suppliers for over 7 million compounds.
• Kompass. Looking for a material? Find a distributor everywhere!
• LookChem. Directory of chemicals and chemical manufacturers from China and the rest of the world.
• Process Register. A large Process Industry Supplier Directory.
• R&D Chemicals. Directory of Companies with products/services for drug discovery industry.
• Suppliers of materials:
• ChemBridge offers an extensive chemistry platform for discovery chemistry.
• ComPlast ComPlex plastics produce Kel-F (poly-chloro-trifluoro-ethylene, PCTFE). Worldwide.
• DuPont Performance Elastomers. Perfluorinated elastomers Kalrez, Viton, Vamac, Neoprene.
• HPFL manufactures aroma and fragrance chemicals. (India)
• Morgan Advanced Ceramics. High-tech ceramics like the machinable Macor.
• Polyflon. Electroplated teflon and capacitors.
• Precision Ceramics produce machinable (Macor, Shapal-M, Boron Nitride, ...).
• QD Information Services provides services to the fine chemical and pharmaceutical industries.
• San Diego Plastics produce Kel-F (poly-chloro-trifluoro-ethylene, PCTFE)
  and the machinable ceramics Mykroy and Mycalex.
• Sigma-Aldrich. A worldwide behemoth.
• Suppliers of tools, instruments, and sensors:
• Franco Corradi. Special ceramics, Peltier elements, temperature sensors, ... (Italy)
• PureAir Monitoring Systems. Monitor/alarm devices for a broad range of gases.
• SKS Science. Affordable labware, containers, scales, books and more. Upstate NY.

EVENTS: Conferences, Major Meetings, ...

• Chemistry Conferences worldwide listings, including Exhibitions, Trade Fairs. Well kept.
• Computational Chemistry Conferences.
• Gordon Research Conferences. Complete 2011 list.
• Keystone Symposia (Biochemistry and Life Sciences).
• Mass Spectroscopy Conferences (and related), some involving also NMR. Worldwide locations.
• Select Biosciences Conferences often involve NMR or MRI. Worldwide locations.