Reevaluation of the Structure and Fundamental Physical Properties of Dawsonites by DFT Studies

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• 作者：Zbigniew 艁odziana ; Georgiana Stoica ; Javier Pe虂rez-Rami虂rez
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：March 21, 2011
• 年：2011
• 卷：50
• 期：6
• 页码：2590-2598
• 全文大小：946K
• 年卷期：v.50,no.6(March 21, 2011)
• ISSN：1520-510X

文摘

Dawsonite-type compounds, with the general formula MAlCO₃(OH)₂, where M = Na⁺, K⁺, or NH₄⁺, recently have become attractive materials because of their potential interest in geochemical CO₂ sequestration, CO₂ capture in power plants, and heterogeneous catalysis. However, the number of studies assessing the properties of these materials is limited. In the present paper, we report a theoretical reevaluation of the structural and essential physicochemical properties of Na-, K-, and NH₄-dawsonites as determined by density functional theory (DFT) investigations. The calculated structure of Na- and K-dawsonites is in good agreement with previous data, while for NH₄AlCO₃(OH)₂, the calculations suggest orientation disorder of the ammonium ions in the structure. The normal-mode analysis, electronic and bonding properties, and elastic properties are reported for the three analogue dawsonites. The calculated formation enthalpy is 鈭?714, 鈭?699, and 鈭?655 kJ/mol for K-, Na-, and NH₄-dawsonite, respectively. This study comprises a first step toward a better understanding of the diversity of dawsonite intrinsic properties, which is required to tune their practical applications.