Sciencemadness Discussion Board

Assining IR spec peak values

tekkado - 6-10-2018 at 13:32

would any one be able to privide some info for the attached spectra?
Im trying to assign the major peaks with values and unsure about the 3000cm-1 region. As there are multiple sharp peaks seen, should each individual peak be assigned a value or would its value be 3100-2900cm-1?

And when looking at charateristic IR absorption tables for these values I see there are ranges for different functional groups (eg. 3000-2800cm-1). Does this mean that the peak should be broad covering this range or that a single peak sould fall somewhere with this range?

gracias

ir spec.jpg - 71kB

Metacelsus - 6-10-2018 at 23:14

Quote: Originally posted by tekkado  
would any one be able to privide some info for the attached spectra?
Im trying to assign the major peaks with values and unsure about the 3000cm-1 region. As there are multiple sharp peaks seen, should each individual peak be assigned a value or would its value be 3100-2900cm-1?

And when looking at charateristic IR absorption tables for these values I see there are ranges for different functional groups (eg. 3000-2800cm-1). Does this mean that the peak should be broad covering this range or that a single peak sould fall somewhere with this range?


Each sharp peak should be listed as its own value.

When ranges are listed, it means that the peak could fall within the range, not that the peak is broad enough to cover the range.

The only really broad IR peak from common functional groups is the O-H stretch. Hydrogen bonding tends to broaden it.