This data set contains the simulation input files, scripts, and figures data belonging to the publication Tuuva Kastinen, Piotr Batys, Dmitry Tolmachev, Kari Laasonen and Maria Sammalkorpi, "Ion-specific effects on ion and polyelectrolyte solvation", ChemPhysChem 2024, e202400244. https://doi.org/10.1002/cphc.202400244 Please cite the above publication when using this data set! This work is supported by the Academy of Finland through its Centres of Excellence Programme (2022–2029, LIBER) under project no. 346111 and 364205 (M.S.) and Academy of Finland project no. 359180 (M.S), Novo Nordisk Founda- tion under project no. NNF22OC0074060 (M.S.), Finnish Cultural Foundation (T.K.), and National Science Centre, Poland under Grant No. 2018/31/D/ST5/01866 (P.B.). We are grateful for the support by the FinnCERES Materials Bioeconomy Ecosystem. Computational resources by CSC IT Centre for Finland, Poland’s high-performance comput- ing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH), grant no. PLG/2023/016229, and RAMI – Raw- Matters Finland Infrastructure are also gratefully acknowledged.

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