This is the dataset corresponding to the publication in the Polymer journal: "Molecular dynamics analysis of iPP-polymorphs; Investigating thermal expansion and elastic properties" Authors: H.N. Chávez Thielemann, J.A.W. van Dommelen, L.E. Govaert, M. Hütter Year: 2024 The dataset presented here provides the chemical structures of iPP crystals, including COMPASS forcefield parameters, as follows: α structures were obtained by repeating the crystalline unit cell 4 times in a, 2 times in b, and 4 times in c (comprising 32 chains and 3456 atoms) alpha2.zip: α2 is the unit cell with perfect up-down alternation. alpha1.zip: α1 is an α2 but with 50% random up-down alternation. A X% of regio defects means that X% of the monomers are incorporated with the inverse head-tail order than in a perfect α2 case.Thus, number of atoms and chains remain unvaried. d2p.zip: α2 containing 2% of regio defects. d4p.zip: α2 containing 4% of regio defects. Vacancy, 31 chains, 3348 atoms: v1.zip: contains the same α2 but with a vacancy, i.e. a complete chain is missing. β structures were obtained by repeating the crystalline unit cell 3 times in a, 2 times in b, and 4 times in c (comprising 36 chains and 3888 atoms) beta2.zip: β2 structure is a monochiral domain, with purely right-handed chains. beta1.zip: β1 structure comprises twelve left- and twenty-four right-handed chains. File names ended with _img indicates that supplementary images are provided for that structure. In most of the cases, the LAMMPS data files are accompanied by a PDB file for completeness. To download them all including extra files at once, then download the archive file 14048060.zip.