INTERPRETATION OF IR SPECTRA
The ir spectra are one of the most useful tool for the analysis of organic compounds. Here are given some examples how an ir spectrum is read. The spectrum for the alkene, 1-hexene, C6H12, has few strong absorption bands. The spectrum has the various CH stretch bands that all hydrocarbons show near 3000cm-1. There is a weak alkene CH stretch above 3000 cm-1. This comes from hydrogen bonds on carbons 1 and 2, the two carbons that are held together by the double bond. The strong CH stretch band below 3000 cm-1 come from carbon- hydrogen bonds in the CH2 and CH3 groups. There is an out of plane CH band for the alkene in the range 1000-650 cm-1. There is also an alkene CC double bond stretch at about 1650 cm-1.