Two pure strontium borates SrB2O4 center dot 4H(2)O and SrB2O4 have been synthesized and characterized by means of chemical analysis and XRD, FT-IR, DTA-TG techniques. The molar enthalpies of solution of SrB2O4.4H(2)O and SrB2O4 in 1 mol dm(-3) HCl(aq) were measured to be -(9.92 +/- 0.20) kJ mol(-1) and -(81.27 +/- 0.30) kJ mol(-1), respectively. The molar enthalpy of solution of Sr(OH)(2)center dot 8H(2)O in (HCl +H3BO3)(aq) were determined to be -(51.69 +/- 0.15) kJ mol(-1). With the use of the enthalpy of solution of H3BO3 in 1 mol dm-3 HCl(aq), and the standard molar enthalpies of formation for Sr(OH)(2)center dot 8H(2)O(s), H3BO3(s), and H2O(l), the standard molar enthalpies of formation of -(3253.1 +/- 11.7) kJ mol(-1) for SrB2O4 center dot 4H(2)O, and of -(2038.4 +/- 1.7) kJ mol(-1) for SrB2O4 were obtained. (c) 2006 Elsevier B.V. All rights reserved.