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CHEM 220. Introductory Instrumental Analysis: Substance search

Names, identifiers, molecular formulas, and more

There are different ways to refer to a chemical substance. Some examples:

- Name. One substance can have many names, including the IUPAC name, trade names, trivial names, etc. For instance, acetaminophen (see structure below) can also be referred to as N-(4-Hydroxyphenyl)acetamidep-hydroxyacetanilide4-(acetylamino)phenol, paracetamoltylenoletc.



Besides, systematic naming conventions are cumbersome and complex in many cases, so sometimes it is not easy to use those when searching the literature

- Identifier. There are several identifiers. CAS assigns the CAS Registry Numbers, which are unique to each substance. For instance, the CAS number of acetaminophen is 103-90-2. One can find CAS numbers in several resources, like NIST Webbook or the CRC Handbook for Chemistry and Physics, and also in chemical suppliers catalogs.

- Molecular formula. One can search by molecular formula, but remember that several compounds can have the same molecular formula. For instance, the molecules in the figure have the same molecular formula:



In-class practice

- Can you find the IR spectrum of caffeine?

- What is the CAS Registry number of taxol?

- For the compound below, find the 1H NMR spectrum:


- Get a SciFinder account: first time users registration.

- Access SciFinder

How to do a substance search in SciFinder

One can search by structure, name, CAS number, and molecular formula. Just keep in mind that molecular formulas are not unambiguous search terms, and that all the possible names of a substance may not be included in SciFinder.