Volumetric properties of aqueous solutions with citrate ions – Trilithium citrate and triammonium citrate

•Densities of aqueous solutions of trilithium and triammonium citrates were measured.•The cubic expansion coefficients and the apparent molar volumes were determined.•Volumetric and thermal properties of aqueous citrate solutions were interrelated.•It was found that these citrates break the structure of water.

Densities of aqueous solutions of trilithium citrate <1.74 mol⋅kg−1 and triammonium citrate <0.20 mol⋅kg−1, were measured at 5 K intervals, from 278.15 K to 343.15 K. These densities served to determine the apparent molar volumes, the cubic expansion coefficients and the second derivatives of volume with respect to temperature which are interrelated with the derivatives of isobaric heat capacities with respect to pressure. Changes in the volumetric properties as a function of temperature and concentration of both citrates are discussed in terms of changes in the structure of water.