کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6660304 1426223 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Heat capacities and thermodynamics of formation of flat-Al13 nitrate - [Al13(OH)24(H2O)24](NO3)15·11H2O
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Heat capacities and thermodynamics of formation of flat-Al13 nitrate - [Al13(OH)24(H2O)24](NO3)15·11H2O
چکیده انگلیسی
We report enthalpies of formation from the elements and oxides, ΔfH∘ = −(26195.31 ± 34.46) kJ · mol−1 and Δf,oxH = −(1402.09 ± 33.36) kJ · mol−1, for crystalline [Al13(μ3-OH)6(μ2-OH)18(H2O)24](NO3)15·11H2O(cr) (flat-Al13) measured using aqueous solution room temperature calorimetry. This material is a nitrate salt of a polynuclear aluminum hydroxide ion with thirteen aluminum metal centers, Al1315+. Unlike the ε-Al137+ Keggin ion, it contains solely octahedrally coordinated aluminum in a more flat topology. We also report heat capacities from temperatures of (2 to 300) K on this flat-Al13 nitrate using a Quantum Design Physical Property Measurement System (PPMS). These measurements were used to calculate the standard molar entropy and subsequently the free energy of formation for this material. We observed that during the heat capacity measurements, the flat-Al13 sample underwent a second order phase transition near T = 214 K.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 90, November 2015, Pages 224-231
نویسندگان
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