NO2:NO2 refers to nitrogen dioxide, a reddish-brown gas with an irritating odor. It is formed during the decomposition of dinitrogen pentoxide (N2O5).
NO3:NO3 represents the nitrate ion, which consists of one nitrogen atom bonded to three oxygen atoms. It is often involved in redox reactions due to its ability to donate or accept electrons.
O2:O2 represents molecular oxygen, which is a diatomic molecule consisting of two oxygen atoms bonded together. It is necessary for respiration and combustion processes.