The XANES spectrum calculated for the PW structure (Figure ) replicated the experimental features seen at -0.1 V, including the additional feature at 3616.3 eV (Feature E) that is not observed for PB. The results validate the assignment of the experimental XANES spectrum to a fully intercalated PW structure, where the sample is fully reduced. Using simulation to validate the spectrum is particularly important given that PW readily oxidized under ambient conditions to PB, making validation via the use of a synthesized material analyzed ex-situ unsuitable. As seen with the simulated spectra of PB with K + within the 8c site, the shoulder of the white line is mispresented in the simulated spectrum of PW, showing that K + continues to be off center from the 8c site within the fully intercalated structure.