DFT-optimized structures of the pyramidal-II stacking fault with a solute in different atomic layers near the fault plane. The dataset include the VASP input files (except POTCAR) and output files OSZICAR and OUTCAR. There are also text files containing the DFT-computed stacking fault energies and chemical misfits, and scripts that calculate these values from the raw DFT output. The README file contains expressions that can be used to compute the chemical misfits using the volumetric size misfit for any substitutional solute species in Mg.