Determination of the local structure and speciation of zinc in individual hypersaline fluid inclusions by micro-XAFS
X-ray absorption fine structure (XAFS) spectra were obtained for the first time from metal complexes in individual fluid inclusions in quartz using the synchrotron X-ray microprobe (X26A) at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory. Analysis of Zn K-edge absorption spectra obtained from hypersaline fluid inclusions in quartz indicate that the dominant complex of zinc in these inclusions at room temperature is ZnCl42-, having a Zn-Cl bond length of 2.33 Å, coordination number of 4.2 atoms and a mean-square relative displacement of the atoms of 0.004 Å2. The presence of ZnCl42- is consistent with results of previous spectroscopic studies of zinc chloride solutions having high Cl/Zn ratios and with solubility studies of zinc compounds in chloride solutions. The results demonstrate the potential of micro-XAFS as a tool for direct measurement of the structure of aqueous metallic species in fluid inclusions.
Anderson, Alan J., Robert A. Mayanovic, and Sasa Bajt. "Determination of the local structure and speciation of zinc in individual hypersaline fluid inclusions by micro-XAFS." The Canadian Mineralogist 33, no. 2 (1995): 499-508.