Bonding in prussian blue (PB) and turnbull blue (TB) films, 30 year room temperature annealed Fe4[Fe(CN)6]3�15H2O stoichiometry, is described by resonance enhanced X-Ray diffraction, and absorption (XRD, XAS) near E0Ea=7126�1eV, Fe K-edge energy. X-Ray excited PB* coordination, [Fe|||(CN-)6Fe||2]+1�[(Fe|||(CN-)4(OH2)2)3)Fe||]-1�9H2O respectively at cube corners and 3 face centers, agrees with enhanced XRD intensity I(E0,Q(?Bragg)) versus ?Bragg, indexed for over two dozen reflections, FCC a*=20.34� cubic cell. Enhanced XRD, at E0-Ea=-{69,42,22,17}eV, is confirmed by XAS absorption peaks at E0-Ea=-{58,53,48,43,35,15, 12}eV. Symmetry allowed transitions, from ground state |Fe:1s2.HOMO> by absorption of an incident photon to LUMO extended states, are followed by scattering and relaxation within t<10-16s to fill half empty Fe K states, and excited state electrons e*(?E,p *), with excess momentum p * and energy ?E, can Compton scatter from 2nd incident photon and from neighbors, before vibration relaxation in t~10-13s. Mutually enhanced PB* reflection pairs, I(E0,Q0)/I*(E0+?E,Q*=|p*+Q0 |)Eo,Qo_constant Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/241nm/uploads/65334_translational_isomer.jpg' alt='' />identify the HOMO/LUMO LCAO constituents by characteristic core energy added to E0, ?E=EN:K_core and EFe:M_core when E0<Ea, and -EFe:L_core when E0>Ea is also confirmed by XAS absorption peaks at E0-Ea={34.8,52,68,79,110,396,472,642 to 842}eV, indicating relaxation after Rydberg excitation, that depletes extended states, repopulates them by resonance absorption. Thus allowed transitions, from core states |Fe:1s2.HOMO|Q0> to |Fe:1s_.LUMO anti-bonding [Fe|||(d2sp3Pauling hybrid)-: N: O(ligands)]> states, determine the ligand bond direction to a* is 54�2o by the I/I*Qo=(640)/(571)/(680)/ (682)/(957)/(12,8,0)/12,10,4)maximum enhancement. C&H Dreyfus, NSF, DOE SLAC-SSRL supported research.

Fe-ligand bonding in Prussian blue by resonance enhanced X-ray diffraction near the Fe K-edge

248th National Meeting (2014)

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