Pointedly focusing on information

GESTIS Database on Hazardous Substances
Contains information for the safe handling
of hazardous substances and other chemical
substances at work.

Encyclopedia of Chemistry

Periodic Table of the Elements
Overview of all chemical elements and their properties

ICSC International Chemical Safety Cards
The ICSC contain essential information for
interacting safely with chemical substances
at the workplace.

National Institute for Occupational Safety and Health

NIST Chemistry WebBook
IR Spectrums, Ionisation Potentials,
Molecular Weights of many substances