Additional information stored in this library include the molecular formula, CAS (Chemical Abstracts Services) registry number, when known, and the location number of the printed spectrum in The Sigma Library of FT-IR Spectra are available on-line. The Sigma location number is in the form:

<volume number> - <page number> <spectrum letter>

For example, the spectrum with the location number 1-234B refers to the second (B) spectrum on page 234 of Volume 1.

Abbreviations Used in Compound Names

Since the compound names associated with the spectra are often very long, in many cases it has become necessary to abbreviate the full name of the substance. The table below defines the abbreviations used in the name field.

In addition to the above abbreviations, occasionally atomic symbols are used in place of element names: e.g., CL = chloro- or chloride. Also, Greek letters (alpha, beta, gamma,...,omega) are given as their lower-case Roman equivalents (a, b, g,...,w), and the standard abbreviations are used for amino acids in polypeptide names.