From my reading, I have understood examples a diatomic molecule to be $\rm N_2$ or $\rm O_2$, however, the below seems to suggest that $\rm N_2O_2$ is also diatomic. Is this correct and can someone please explain?
My answer for the below question was 6 degrees of freedom (3 translational, 3 rotational, not high enough temperature for vibrational).
Q. The main components of air are $\rm N_2$ and $\rm O_2$. Assume that we can approximate air as only made from these two gasses. At room temperature how many degrees of freedom does air have? State what type of movement (vibrational, rotational and translational) each of these degrees of freedom corresponds to.
Ans. This is a diatomic gas at approximately room temperature. It has 5 degrees of freedom. 3 of these degrees of freedom correspond to the translational movement of the particles (one in x, one in y and one in z direction) and 2 correspond to the rotational movement of the molecules (abut the two axes perpendicular to the line joining the two atoms).