Finding Chemical Spectra and Spectral Data
Spectra Sources on the Web
There aren't many Web-based spectral libraries that are freely available, sizeable, and of high quality. Most free sites have relatively few spectra compared to commercial subscription libraries. If you find a spectrum on a free site, evaluate it carefully and consider its source and methodology. These sites are listed alphabetically, with a star 
indicating a particularly useful resource.
- Biological Magnetic Resonance Data Bank
- Quantitative data derived from NMR spectroscopic investigations of biological macromolecules. (Univ. of Wisconsin)
- ChemExper Chemical Directory
- CCD contains IR spectra (via interactive applet) for various compounds. The directory can be searched by registry number, molecular formula, chemical name or synonyms in different languages as well as by physical and chemical characteristics and combinations of those data. The CCD may also be searched by substructure. The data are submitted from various sources and should not be considered critically evaluated.
- ChemGate
- A pay-per-view site offering 700,000 NMR, IR and MS spectra from the Wiley spectral data collections. Searching by structure drawing, name, CAS registry number, or SMILES, and browsing by method or compound class are free. After that, get out your credit card. (Wiley-VCH)
- Combined Chemical Dictionary
- Database containing detailed information and spectral data (but not spectral diagrams) on over 500,000 chemical substances and their derivatives. Includes some selected literature references to original articles.
- EPA/USAF Spectral Database
- Spectra and spectroscopic data of species of interest to the pollution monitoring and gas diagnostics community. Spectra files are in .spc format, requiring a special viewer such as ShowSPC.
- Mineral Spectroscopy Server
- Files of visible, Raman, and IR spectra of minerals, plus links to other collections. (Caltech)
- NIST Atomic Spectra Database
- "The Atomic Spectra Database (ASD) contains data for atom and ion transitions, and energy levels. Lines are included for the first 99 elements in the periodic table. The energy level tables also contain ionization limits. ASD contains data on about 950 spectra, with about 144,400 lines from 0.4 to 5,000,000 angstroms in wavelength, plus about 77,000 energy levels."
- NIST Chemistry WebBook
- The WebBook contains IR spectra for over 8700 compounds, mass spectra for over 12,600 compounds, electronic / vibrational spectra for over 4100 compounds, UV/VIS spectra for 400 compounds, constants of diatomic molecules (spectroscopic data) for over 600 compounds, and ion energetics data for over 16,000 compounds, etc.
- NIST Molecular Spectra Databases
- "Three databases of diatomic, triatomic, and hydrocarbon molecules were originally published as spectral tables in the Journal of Physical and Chemical Reference Data. Each covers primarily the microwave region with some data for the radio frequency region. Rotational spectral lines for 121 diatomic molecules, 55 triatomic molecules, and 91 hydrocarbons have been tabulated. The isotopic molecular species, assigned quantum numbers, observed frequency, estimated measurement uncertainty, and reference are given for each transition."
- NIST X-Ray Photoelectron Spectroscopy Database
- Provides "access to the energies of many photoelectron and Auger-electron spectral lines. Resulting from a critical evaluation of the published literature, the database contains over 22,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines. A highly interactive program allows the user to search by element, line type, line energy, and many other variables. Users can easily identify unknown measured lines by matching to previous measurements."
- NMRShiftDB
- Web database for organic structures and their NMR spectra. It allows for spectrum prediction as well as for searching spectra, structures and other properties. It features peer-reviewed submission of datasets by users. Some browser compatibility issues; must have JavaScript and Java VM enabled.
- Properties of Organic Compounds
- Provides spectral peaks (no diagrams) on about 25,000 important organic substances.
- RRUFF (Raman Spectra of Minerals)
- "The RRUFF Project is creating a complete set of high quality spectral data from well characterized minerals and is developing the technology to share this information with the world. Our collected data sets the standard for mineralogists, geoscientists, gemologists and the general public for the identification of minerals both on earth and for planetary exploration." Entries include photos of the sample, collected data, and measured chemistry in addition to the locality and source. (Univ. of Arizona)
- SciFinder (Registry)
- CAS has added experimental spectra for over 700,000 compounds in the Registry database. IR, MS and NMR spectra are from Wiley spectral databases and the Japanese SDSB database. In addition, CAS has added millions of predicted proton NMR spectra from ACD Labs.
- SDBS - Spectral Database System
- Large database of organic spectra, with thousands of IR, 1H-NMR, 13C-NMR, mass, and ESR spectra, searchable by name, formula, Registry Number, NMR shifts, and MS peaks. (National Institute of Materials and Chemical Research, Japan)
- Sigma-Aldrich Catalog
- FT-IR/Raman and NMR spectra of most compounds in the catalog are downloadable as PDF files. Search by catalog number, name, formula, CAS registry number. Chemical/physical information, structure image are displayable.
--Polymers and Macromolecules 
--Drugs 
