Densities of six ILs were measured from T = (278.15 to 398.15) K and up to 120 MPa.
[C1C1Im][(C1O)2PO2] has a compressibility around half of those of hydraulic fluids.
Gardas–Coutinho method predicts density of five ILs with ADDs lower than 1.8%.
κT at 0.1 MPa was predicted with Kiselev et al. equation with an overall AAD of 2.3%.