A chronoamperometry experiment was performed on a \(4.00 \mathrm{mM}\) solution of an iron(III) complex at \(25^{\circ} \mathrm{C}\) using a platinum electrode with an area of \(0.075 \mathrm{~cm}^{2}\). The potential was stepped from a voltage that was \(100 \mathrm{mV}\) more positive than the \(\mathrm{E}^{\circ ´}\) out to a value that was \(100 \mathrm{mV}\) more negative than \(\mathrm{E}^{\circ ´}\) where a one-electron reduction occurs. The data for the current-time curve are given below. Calculate the diffusion coefficient for the iron(III) complex under these conditions.

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Current (A) 1.00E-03 9.00E-04 8.00E-04 Chronoamperometry Expt. 7.00E-04 6.00E-04 5.00E-04 4.00E-04 3.00E-04 2.00E-04 1.00E-04 0.00E+00 0 0.005 0.01 0.015 0.02 0.025 Time (s) Time 0.002 Current (A) 9.06E-04 0.003 7.39E-04 0.005 5.73E-04 0.008 4.53E-04 0.01 4.05E-04 0.012 3.70E-04 0.015 3.31E-04 0.02 2.86E-04