Energetics of Al₁₃ Keggin cluster compounds.

ABSTRACT: The ε-Al(13) Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ε-Keggin clusters, Al(13) selenate, (Na(AlO(4))Al(12)(OH)(24)(SeO(4))(4)•12H(2)O) and Al(13) sulfate, (NaAlO(4)Al(12)(OH)(24)(SO(4))(4)•12H(2)O). The measured enthalpies of solution, ΔH(sol), at 28 °C in 5 N HCl for the ε-Al(13) selenate and sulfate are -924.57 (± 3.83) and -944.30 ( ± 5.66) kJ·mol(-1), respectively. The enthalpies of formation from the elements, ΔH(f,el), for Al(13) selenate and sulfate are -19,656.35 ( ± 67.30) kJ·mol(-1), and -20,892.39 ( ± 70.01) kJ·mol(-1), respectively. In addition, ΔH(f,el) for sodium selenate decahydrate was calculated using data from high temperatu

SUBMITTER: Armstrong CR 

PROVIDER: S-EPMC3169149 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature