Interpretation of 1H NMR 4-vinylbenzoic acid

Please see the attached document.

NiCl2(dppe) IR

I need to assign the peaks at 530cm-1, 490cm-1, 395cm-1 and 330cm-1 for teh IR spectrum of NiCl2(dppe) and I don't have the right books for it. Please see the attached file and please could you reference where you got the information to label those peaks.

Cyclohexene oxide 1H NMR

Please see the attachment. I started doing it, but I'm not sure if it's right and also I still don't understand about the doublet of doublet of doublet etc. and not sure if the hydrogens highlighted are ddd.

Lowest energy spectroscopic terms

A. Show what electronic arrangements (electrons occupying sub shells of different ml and ms) that would lead to spectroscopic terms 6H, 5I and 8S, and identify one element each that have these terms as (see attached) the lowest energy spectroscopic terms.

Infrared spectroscopy

On this site http://www.chemguide.co.uk/analysis/ir/interpret.html#top it shows an infra red spectrum of ethanoic acid and shows a very broad trough between 2500 - 3300 cm ^-1 taking this from the point where the line graph starts to drop it looks more like 2800 - 3800 cm ^-1 do you have to take these measurements from the centre as it is most accurate . The absorption starts from where the line starts to drop. why take it from the centre?