Answer
The name of the compound is dinitrogen pentoxide.
Work Step by Step
The name of the compound ($N_2O_5)$ is the name of the first element, nitrogen, prefixed by $di-$ to indicate two, followed by the base name of the second element, $ox$, prefixed by $pent-$ to indicate five and given the suffix -ide. So, the name of the compound is dinitrogen pentoxide.
