Nanoscale species often play critical roles as intermediate species in environmental systems. Understanding the reaction pathways and processes that act on these intermediates allows researchers to better predict various system descriptors, ranging from likely formation products to contaminant transport. Thermodynamic measurements utilizing these nanometer-size molecular clusters provide the necessary bridge between theory and experiment. Here we report thermodynamic results for several molecular clusters measured with isothermal acid solution calorimetry. We compare the thermochemistry of the e-Al13-Keggin, Na(AlO4)Al12(OH)24(H2O)12(SeO4)4�   xH2O, to the corresponding selenate salt of the gallium-centered Keggin, e-GaAl12: Na(GaO4)Al12(OH)24(H2O)12(SeO4)4 �   xH2O. Additionally, we report thermodynamic data for flat-Al13 solids, and similarly compare their thermochemistry to that of the e-Al13-Keggin solids. This work contributes to the chemistry that governs the structure, bonding, reactivity, and stability of molecular clusters facilitating the design of new clusters and materials.

Aluminum hydroxide clusters in environmental systems: A comparison of the thermochemistry of solid &epsi;-GaAl12 and flat-Al13 to &epsi;-Al13 Keggin compounds

245th National Meeting (2013)

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