Osmium can be oxidated to +8 and forms a smelly tetroxide.
Ruthenium, above Osmium in the same group, can be oxidated to +8 and forms a smelly tetroxide.
Iron, above Ruthenium in the same group can only be oxidated to +7 and it's oxides correspondingly lack odor.
Why can't iron oxidize to +8? It's got enough electrons for it.