Energetics of Formation and Oxidation of Microporous Calcium Aluminates: A New Class of Electrides and Ionic Conductors
Energetics of Formation and Oxidation of Microporous Calcium Aluminates: A New Class of Electrides and Ionic Conductors
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DOI：
10.1021/cm051662w
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发表时间：
2005-09
影响因子：
8.6
通讯作者：
Olga Trofymluk;Y. Toda;And Hideo Hosono;A. Navrotsky
中科院分区：
文献类型：
--
作者：
Olga Trofymluk;Y. Toda;And Hideo Hosono;A. Navrotsky
Microporous calcium aluminates with a common formula [Ca12Al14O33-δ]2δ+(2δe-), (0 < δ ≤ 1), represent a new family of electrides with conducting extraframework electrons encaged within the framework. Their enthalpies of oxidation to eliminate these electrons and obtain a stoichiometric Ca12Al14O33 compound, and formation enthalpies relative to the most stable annealed calcium aluminate Ca12Al14O33.46 (which contains excess oxygen probably as O- and O2- species), are studied by transposed temperature drop calorimetry and drop solution calorimetry in molten lead borate at 1080 K. The standard enthalpy of oxidation per O2 consumed is −579.4 ± 9.4 kJ/mol (or −144.8 ± 9.4 kJ per encaged electron). The enthalpies obtained for samples with variable amounts of electrons (and less than 33 oxygens per formula unit) are compared to that for oxidation of a stoichiometric Ca12Al14O33 sample to an oxygen-rich composition. The study supports the idea that the oxidation of the stoichiometric Ca12Al14O33 sample results in...
