Electron Transport Chain is shown in the image.Complex IV is marked in the image.Cyanide is an inhibitor of Complex IV.
Inhibitors of ETC:
Cyanide:Inhibitor of Complex IV/Cytochrome Oxidase.
Barbiturates and Rotenone:Inhibitor of Complex I/NADH dehydrogenase
Oligomycin:Inhibitor of F0 component of FoF1 ATP synthase.