Standard molar enthalpy of formation of Ca 2[B 4O 7(OH) 2]

• Published in: Thermochimica acta Vol. 433; no. 1; pp. 196 - 199
• Main Authors: Liu, Zhihong, Li, Saying, Zuo, Chuanfeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2005
• Subjects: Ca 2[B 4O 7(OH) 2]; Solution calorimetry; Standard molar enthalpy of formation; Standard molar enthalpy of formation; Solution calorimetry; Ca 2[B 4O 7(OH) 2]
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2005.03.010

A pure calcium borate Ca 2[B 4O 7(OH) 2] has been synthesized under hydrothermal condition and characterized by XRD, FT-IR and TG as well as by chemical analysis. The molar enthalpy of solution of Ca 2[B 4O 7(OH) 2] in HCl·54.549H 2O was determined. From a combination of this result with measured enthalpies of solution of H 3BO 3 in HCl·54.517H 2O and of CaO in (HCl + H 3BO 3) solution, together with the standard molar enthalpies of formation of CaO(s), H 3BO 3(s), and H 2O(l), the standard molar enthalpy of formation of –(4398.9 ± 3.8) kJ mol −1 for Ca 2[B 4O 7(OH) 2] was obtained.