Synthesis and thermodynamic properties of nano magnesium borate MgBO 2 (OH) with three different morphologies

MgBO 2 (OH) with flower-like, sea urchin-like, and rice panicle-like morphologies have been synthesized and characterized by XRD, FI-IR, SEM and TEM. The molar enthalpies of solution of MgBO 2 (OH) with different morphologies in 3.00 mol·L − 1 HCl(aq) were measured. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 in 3.00 mol·L − 1 HCl(aq), the enthalpy of solution of MgO in (HCl + H 3 BO 3 )(aq) and the standard molar enthalpies of formation of MgO(s), H 3 BO 3 (s) and H 2 O(l), the standard molar enthalpies of formation of MgBO 2 (OH) with flower-like, sea urchin-like, and rice panicle-like morphologies were calculated to be -(1465.40 ± 1.44), -(1464.32 ± 1.31) and − (1476.62 ± 1.46) kJ·mol − 1 , respectively. The results show that the morphology and crystal structure of the sample have an effect on its standard molar enthalpy of formation, and the crystal structure has a greater influence.