EXAFS absorption coefficients for Ni sorbed to 4 experimental samples of birnessite

EXAFS absorption coefficients as a function of X-ray energy for the four experimental samples whose spectra are presented in Figure 4 of Wasylenki et al., Toward mending the marine mass balance model for nickel: experimentally determined isotope fractionation during Ni sorption to birnessite, Geochimica et Cosmochimica Acta, in revision as of 2024/03/17. Data collection and fitting methods are described therein.

There are two samples each from low ionic strength (high and low surface loading) and from high ionic strength experiments (high and low surface loading), as labeled in the spreadsheet. Our objective was to determine the fraction of Ni that was sorbed as triple-corner-sharing complexes on [001] surfaces above Mn vacancies, as opposed to incorporated into the structural Mn vacancies.