FTIR Scaling Slightly off in Virtual Organic Lab?

It is just me, or is the x-axis slightly off on the FTIR data in the Virtual Organic Lab? For example, the IR of diethyl ether has a peak at around 3040 wavenumbers that is typically reported as being closer to 2990 in the literature. In the same spectrum, the peak at 1130-ish is spot-on, so it’s more like the axis is slightly stretched, particularly between 2200 and 4500 wavenumbers.

I’ve noticed this in many (most?) of the spectra, so I don’t think it’s unique to diethyl ether, but it can make it a bit difficult to distinguish between alkyl C-H bonds and aryl/vinyl C-H bonds, since the “3000 line” is slightly off.

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My name is Jake and I am the chemistry technician/ TA for most chemistry at Yeshiva University in NYC. One of the organic chemistry lab instructors recently noticed this for Ethyl heptanoate which is one of the unknowns in the qualitative analysis lab. He States:
What is odd about the IR is the position of the CH peaks, which LabZ shows to be well above 3000 cm-1, which makes no sense. Indeed, the AIST spectrum shows no peaks above 3000.
Did you here anything from labz concerning this matter? Are they aware of it?

Thanks and be well

I agree that it’s problematic with FTIR interpretation (particularly of unknowns). @heather @ludwig are both in the admin group, so maybe they can comment about this issue (or at least forward our concerns to the development team).

Hi csjoiner and jherman,

Yes, we are aware of the incorrect position of the high frequency IR peaks in a number of the spectra. We are working to make the necessary corrections. I cannot yet tell you when the updates will be complete, but I want to thank you both for noting this.


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