where the 𝐾 𝐴𝑄_𝑎𝑑𝑑𝑢𝑐𝑡 and 𝐾 𝑝𝑟𝑜𝑡𝑜𝑛𝑎𝑡𝑖𝑜𝑛 are the 𝐴𝑄(𝐶𝑂 2 ) 2 2-adduct formation and protonation equilibrium constants, respectively. Both reactions can occur in two steps, involving the sequential acceptance of the first CO2 or H + molecule followed by the second. The experimental determination of 𝐾 𝐴𝑄_𝑎𝑑𝑑𝑢𝑐𝑡 is elucidated in the next section through cyclic voltammetry, although extracting the equilibrium constant for the initial step in isolation presents challenges. Conversely, the double step protonation can be deduced from the Pourbaix diagram, from the pKa1 and pKa2 of the compound, resulting in the following equilibrium equations: