Chemistry

Cambridge Soft ChemFinder
Chemical database searchable by name, formula, molecular weight, melting & boiling points, CAS RN, and structure. Includes basic physical characteristics and numerous links to additional information.

Chemical Acronyms Database
From the University of Indiana, this database includes about 8,000 acronyms and abbreviations related to chemistry.

MegaConverter
MegaConverter is a set of weights, measures and units conversion/calculation modules. Density, force,energy, etc.

Molecular Weight Calculator
Search for molecular weight and physical molecular weight by chemical molecular formula.

NIST Chemistry WebBook
This site provides thermochemical, thermophysical, and ion energetics data compiled by NIST under the Standard Reference Data Program. Search by name, formula, CAS registry number, and other data.

Web Elements™ Periodic Table
Search for more than just atomic number and weight. Find out a brief history as well as a bunch of chemical data for everything from Hydrogen to Meitnerium. Check out the new beta version which includes nifty graphics.

SCOP: Structural Classification of Proteins
Provides a detailed and comprehensive description of the structural and evolutionary relationships between all proteins whose structure is known. Browse the SCOP hierarchy or search by keyword. From the Cambridge, England-based MRC Laboratory of Molecular Biology and Centre for Protein Engineering.