Which of the following does not exist?

As $\mathrm{Xe}$ and $\mathrm{Ne}$ both are inert gases, but $\mathrm{Xe}$ can form compounds with Oxygen and Fluorine because of its large size.

$\mathrm{Ne}$ is smaller in size and highly inert thus exists in atomic form only and do not form a molecule with another atom, as it is highly non-reactive.

Thus, ${\mathrm{NeF}}_2$​ does not exist.