The enthalpies of dilution have been measured for aqueous Li2B4O7 solutions from 0.0212 to 2.1530 mol kg(-1) at 298.15 K. The relative apparent molar enthalpies, L-phi, and relative partial molar enthalpies of the solvent and solute, (L) over bar (1) and (L) over bar (2) were calculated. The thermodynamic properties of the complex aqueous solutions were represented with a modified Pitzer ion-interaction model. (C) 2005 Elsevier B.V. All rights reserved.