The dataset provides an introductory level representation of the n(FeS2)(p) nanoparticles with n=4, n=8, n=18, and n=32 Fe ions. In addition to the paramagnetic and coupled peripheral Fe ions, the latter two compositions involve one and six, low spin, bulk Fe2+ sites as in the pyrite crystal structure. Calculations were carried out at the MN15/def2SVP level along with all models being embedded into a polarizable continuum model (SMD). The zip files contain representative files that support the XYZ Cartesian Coordinate files. They include spin density contour plots, formatted checkpoint files, the corresponding cube and the output files. Initial model structures were created using the high resolution, low temperature crystal structure An extension is being curated in order to disseminate the structure and electronic properties/features of these nano-scale models of reactive pyrite surfaces. Please stay tuned for further updates ...