Fig. 3: Electronic and atomic coordination structures of Na_xMn₃O₇.

a XRD pattern of Na₂Mn₃O₇. Normalized Mn K-edge XANES spectra (b) and EXAFS oscillation functions (c) of Na_xMn₃O₇ (x = 2.0, 1.5, 1.0 and 0.7). d Fourier transform magnitudes of Mn K-edge EXAFS k²χ(k). Mn L_2,3-edge (e) and O K pre-edge (f) of soft XAS spectra of Na₂Mn₃O₇ and NaMn₃O₇.