This three volume set includes over 18,000 spectra categorized by chemical functionality and arranged in order of increasing structural complexity. All spectra were run in the Aldrich quality control laboratories and confirmed by other spectroscopic and chromatographic analyses. The library includes extensive cross-references by chemical name, molecular formula, CAS number, and Aldrich catalog number. The Aldrich Collection of FT-IR Spectra Edition II library contains spectra of 18,454 pure compounds and comes with the Second Edition of the Aldrich Library of FT-IR Spectra (a 3-volume book set).All spectra were acquired by Sigma-Aldrich Co. and were processed by Thermo Fisher Scientific. This library represents the largest collection of spectra collected entirely by FT-IR instrumentation. Eight smaller Aldrich Material Specific Sub-Libraries are also available.