CHEM 143A-D: Organic Chemistry Laboratory: Home

Resources to help you find information (articles, data, etc.) for your organic chemistry lab experiments. Shortcut:

Wireless & Off-Campus Access

Most of the resources on these pages are licensed by UCSD. Wifi and off-campus access are restricted to students, faculty, and staff.

Hill Order?

Molecular formulas are often written using the Hill System. Some databases like Reaxys also use this system (NaCl becomes ClNa).

  • Start with carbon, then hydrogen, then the rest of the in alphabetical order (C2H5AlCl2)
  • If there's no carbon, write all of the elements in alphabetical order (ClHN4)

Find Basic Information About Your Compound

Excellent databases to find basic information about chemical compounds: molecular weight, CAS Registry numbers and common physical property data.  

Your Librarian

Teri Vogel
Geisel Library, West Wing
Social:Twitter Page

CAS Registry Numbers?

CAS Numbers are unique identifiers assigned to substances by Chemical Abstracts Service and maintained in their CAS Registry. You can use the CAS-RNs to locate information for a chemical in numerous print and online sources. CAS assigned ~15,000 new numbers every day.


  • 58-08-2 (caffeine)
  • 1411769-41-9 (CAS' 70 millionth substance, registered November 14, 2012)
  • 1458220-76-2 (added October 15, 2013)