Redox Couple
The oxidised and reduced forms of the same species, considered together as a conjugate pair.
Formula / equation
Ox / Red
Unit
V
In depth
Every half-reaction defines a couple, written with the oxidised form first and separated by a slash. Each couple has a characteristic standard potential, and comparing two couples' potentials predicts immediately which direction the overall reaction will take.
Examples in the real world
Zn²⁺/Zn at −0.76 V and Cu²⁺/Cu at +0.34 V, whose combination gives a 1.10 V cell.