This dataset includes X-ray diffraction (XRD), Raman spectroscopy, and X-ray absorption near edge structure (XANES) data from Phillips et al. (2023)- "The role of manganese oxide mineralogy in thallium isotopic fractionation upon sorption". This project aimed to determine the degree of Thallium (Tl) isotope fractionation upon sorption to Mn oxide minerals triclinic birnessite and todorokite. The XRD and Raman spectra indicate structural changes in the mineralogy of triclinic birnessite upon Tl sorption. The XANES spectra show that Tl and Mn oxidation states remain relatively constant before and after Tl sorption, indicating that no Tl oxidation or Mn reduction occurs during Tl sorption to triclinic birnessite or todorokite.