Synthesis, characterization and thermochemistry of 2MgO• B2O3•1.5H2O

A new magnesium borate 2MgO (.) B2O3 (.) 1.5H(2)O has been synthesized by the method of phase transformation of double salt under hydrothermal condition and characterized by XRD, IR, Raman spectra and TG. The enthalpy of solution of 2MgO (.) B2O3 (.) 1.5H(2)O in 2.9842 mol (.) L-1 HCl was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in 2.9842 mol (.) L-1 HCl (aq.) and of MgO in (HCl + H3BO3) solution, together with the standard molar enthalpies of formation of MgO(s), H3BO3(S), and H2O(l), the standard molar enthalpy of formation of -(3019.76 +/- 1.79) kJ (.) mol(-1) of 2MgO (.) B2O3 (.) 1.5H(2)O was obtained.