10.26165/JUELICH-DATA/PCZCKP Ait Mouheb, Naila(Institute of Energy and Climate Research – Nuclear Waste Management (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany)Macé, Nathalie(Université Paris-Saclay, CEA, Service d’Etude du Comportement des Radionucléides, 91191, Gif-sur-Yvette, France)Henocq, Pierre(Research and Development Division, Andra, 1-7 Rue Jean Monnet, Parc de la Croix Blanche, 92298 Chatenay-Malabry Cedex, France)Bosbach, Dirk(Institute of Energy and Climate Research – Nuclear Waste Management (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany)Deissmann, Guido(Institute of Energy and Climate Research – Nuclear Waste Management (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany) Jülich DATA 2023 The experimental data consist of derived sorption parameters for 241Am and 152Eu under CEM V/A HCP cementitious materials as a function of phthalic acid additions. Solubility data obtained from thermodynamic modelling demonstrate the impact of phthalic acid on the speciation and solubility of 241Am and 152Eu as a function of pH. In addition of calculated Ca-speciation in the solution equilibrated with HCP CEM V/A as function of the phthalic acid concentration. Ait Mouheb, Naila(Institute of Energy and Climate Research – Nuclear Waste Management (IEK-6), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany)