General

UK Chemistry Departments
http://www.liv.ac.uk/Chemistry/Links/ukchemdepts.html
Links to UK chemistry departments.

International Chemistry Departments
http://www.liv.ac.uk/Chemistry/Links/international.html
Links to chemistry departments outside the UK.

Oxford University, Department of Chemistry
http://www.chem.ox.ac.uk/vrchemistry/
Oxford's virtual chemistry laboratory.

Sheffield University, Department of Chemistry
http://www.chemdex.org/
The Sheffield Chemdex: a directory of chemistry on the World Wide Web.

HyperPhysics
http://hyperphysics.phy-astr.gsu.edu/hphys.html
A site which has information on almost all chemistry topics.

PSIGATE: Physical Science Information Gateway
http://www.psigate.ac.uk
PSIgate is a free service that offers access to high quality Web resources in the physical sciences.

Databases

NIST Chemistry Webbook
http://webbook.nist.gov
The NIST Chemistry Webbook provides access to data compiled and distributed by NIST.

Conversion Factors for Energy Equivalents from NIST
http://physics.nist.gov/cuu/Constants/energy.html
Very useful compilation of conversion factors from the National Institute of Standards and Testing (NIST).

CRC Handbook of Chemistry and Physics
http://hbcpnetbase.com
Excellent source of data in nearly all aspects of chemistry. Data may be accessed after purchasing a personal or institutional subscription.

Fundamental Physical Constants from NIST
http://physics.nist.gov/cuu/Constants
Essential compilation of currently accepted values for fundamental physical constants.

International System of Units from NIST
http://physics.nist.gov/cuu/Units/index.html
A useful introduction to the SI system of units.

NIST Elemental Data Index
http://physics.nist.gov/PhysRefData/Elements/index.html
Very useful compilation of data on elements by the NIST.

NIST Guidelines for Evaluating and Expressing Measurement Uncertainty
http://physics.nist.gov/Pubs/guidelines/contents.html
This document is based on NIST Technical Note 1297, 1994 Edition. The compilation is especially useful for instructors and students in physics, physical chemistry, and analytical chemistry courses.

WebElements Periodic Table of the Elements
http://www.webelements.com/webelements/scholar/index.html
Interactive periodic table of the elements, with extensive tabulation of physical and chemical properties.

IUPAC
http://www.iupac.org/reports/1993/homann/index.html
Abbreviated list of quantities, units and symbols in physical chemistry.

Societies

Royal Society of Chemistry
http://www.rsc.org
Contains useful information on and additional links in all areas of chemistry.

The RSC's Chemical Science Network
http://www.chemsoc.org/
A huge range of chemistry resources including: chemsoc's online magazine, with features on "hot topics" in chemical science; information on conferences and events; learnnet, a comprehensive resource for teachers and students of chemistry to learn more about their subject; advice on careers and jobs and lots more.

American Chemical Society
http://www.acs.org
Contains useful information on and additional links in all areas of chemistry.

American Physical Society
http://www.aps.org
Contains useful information on and additional links in areas of physics that overlap with areas of chemistry, such as materials science, laser science, spectroscopy, and computational science.

Biophysical Society
http://www.biophysics.org
Contains useful information on and additional links in areas of biophysics that overlap with areas of physical chemistry, such as biological spectroscopy and imaging, thermochemistry, dynamics, and computational biosciences.

American Geophysical Society
http://www.agu.org/
Contains useful information on and additional links in the areas of Earth and planetary science.

Software

Mathcad
http://www.mathsoft.com
Mathematical software by MathSoft widely used in physical chemistry and engineering. The full program is available for purchase.

Mathematica
http://www.wolfram.com/products/mathematica
Mathematical software by Wolfram Research. It is widely used by mathematicians and physicists. The full program is available for purchase, but the viewer program, MathReader, may be downloaded at no cost.

ODE Software for Matlab
http://math.rice.edu/~dfield
A free interactive utility that solves ordinary differential equations. Very useful in the study of kinetics and transport, but the on-line documentation is poor.

Symbolic Mathematics Documents for Physical Chemistry
http://www.monmouth.edu/~tzielins/mathcad
An excellent and very extensive collection of Mathcad files maintained by Prof. Theresa Zielinksi, Monmouth University. Includes a useful tutorial on the basics of Mathcad.