Water and Science
Suggestions to begin a Six Week Study
Water and Science (Plan A)
National Institute of Standards and Technology (NIST)
Has entries for a large number of molecules, but has no data for many of them. Good source for data on relatively common molecules (and faster than trying to find them in the old NIH/EPA tomes).
Oxford Physical Chemistry MSDS (Material Safety Data Sheet) database.
Has links to a number of chemical safety resources, but the page can be kind of a pain in the ass to navigate. A wise person would set google to search the domain 'http://physchem.ox.ac.uk' for the name of the molecule they are searching for.
It allows a user to search by data characteristics (peak ranges, etc) rather than by moecule information.
Spectral Database for Organic Compounds
Allows the user to search by molecular composition, MS data, mass, name, CAS registry #, and a couple of other options. Despite the .co.jp address, everything seems to be in legible english.