Rhodium ($\mathrm{Rh}$)

Rhodium is a platinum-group transition metal with chemical symbol $\mathrm{Rh}$ and atomic number $45$. Both its metallic surfaces and its coordination complexes are important in catalysis; automotive exhaust treatment is a major application.^[ref]

Different ligand environments can change a rhodium centre's accessible oxidation states and reaction pathways. Thus the relatively unreactive bulk metal and a reactive molecular rhodium catalyst are compatible descriptions of different chemical environments, rather than contradictory properties of the element.