The Cambridge Structural Database (CSD)
The Cambridge Crystallographic Data Centre (CCDC)

CHEMnetBASE
Suchfunktion zu "CRC Handbook of Chemistry and Physics" und anderen Nachschlagewerken

ChemSpider
Access to millions of chemical structures - RSC

Crystallography Open Database
Including data and software from CrystalEye

A Dictionary of Units
Cleave Books (Masseinheiten und deren Umwandlung)

Eigenschaften-Quellen-Index
Informationszentrum Chemie Biologie Pharmazie - ETHZ

eMolecules
Search over 6 million unique structures for technical and supplier

IUPAC Compendium of Chemical Terminology
"Gold Book" This online version corresponds to the second edition, compiled by Alan D. McNaught and Andrew Wilkinson.

IUPAC Nomenclature of Organic Chemistry
Published with permission of the IUPAC by ACD

molMall
Partner of the MDPI Sustainability Foundation

NIST Physical Reference Data
National Institute of Standards and Technology, USA (Physikalische Konstanten und Daten)

RIO-DB
National Institute of Advanced Industrial Science and Technology, Japan (u.a. Spektren)

Sigma-Aldrich
Zugang zu den Katalogen verschiedener Chemikalien-Hersteller

Synthesis Reviews
Database of 20'000 review articles of interest to synthetic organic chemists, University of Leeds

WebElements
Anklickbares Periodensystem, Mark Winter, University of Sheffield, England

ATSDR
AGENCY FOR TOXIC SUBSTANCES AND DISEASE REGISTRY

ChemView
U.S. Environmental Protection Agency

GESTIS Stoffdatenbank
Gefahrstoffinformationssystem der gewerblichen Berufsgenossenschaften

Lebensmittelzusatzstoffe (E-Nummern)
Die Verbraucher Initiative, Bonn

NIOSH DATABASES
u.a. "International Chemical Safety Cards"

TOXNET
Toxicology Data Network

BLAST® 
(Basic Local Alignment Search Tool) A set of similarity search programs designed to explore all of the available sequence databases regardless of whether the query is protein or DNA.

ExPASy Bioinformatics Resource Portal
Schweizerisches Instituts für Bioinformatik (SIB)

BRENDA
The Comprehensive Enzyme Information System, Cologne University BioInformatics Center, Academic Use of BRENDA is free - Commercial Use requires a license

EMBL
Datenbanken des "European Bioinformatics Institute" (EBI; u.a. Nucleotide Sequence Database)

NCBI Entrez
Datenbanken des "National Center for Biotechnology Information" (u.a. GenBank)

PDB
Protein Data Bank des "Research Collaboratory for Structural Bioinformatics (RCSB)"

UniProt
Proteindatenbanken Swiss-Prot, TrEMBL und PIR