Oxygen binds to the 1) hb 2) mb 3) hemocyanin. in the form of ??

for hb and mb in terms of superoxide which has stretching frequency of 1100cm-1 and in hc it binds in terms of peroxide which has stretching frequency of 850cm-1

https://chemed.chem.purdue.edu/genchem/topicreview/bp/1biochem/blood3.html check this link

for Hb and Mb ?

in the form of O2^-2(peroxy)