We have used Mn K–edge absorption and Kβ emission spectroscopy to determine the oxidation states of the Mn complex in the various S states. We have started exploring the new technique of resonant inelastic X–ray scattering spectroscopy; this technique can be characterized as a Raman process that uses K–edge energies (1s to 4p,
ca
. 6550 eV) to obtain L–edge–like spectra (2p to 3d,
ca
. 650 eV). The relevance of these data to the oxidation states and structure of the Mn complex is presented. We have obtained extended X–ray absorption fine structure data from the S
0
and S
3
states and observed heterogeneity in the Mn–Mn distances leading us to conclude that there may be three rather than two di–
μ
–oxo–bridged units present per tetranuclear Mn cluster. In addition, we have obtained data using Ca and Sr X–ray spectroscopy that provide evidence for a heteronuclear Mn1Ca cluster. The possibility of three di–
μ
–oxo–bridged Mn–Mn moieties and the proximity of Ca is incorporated into developing structural models for the Mn cluster. The involvement of bridging and terminal O ligands of Mn in the mechanism of oxygen evolution is discussed in the context of our X–ray spectroscopy results.
Antiferromagnetic Order and Spin-Canting Transition in the Corrugated Square Net Compound Cu3(TeO4)(SO4)·H2O
