Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate
Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium carbonate
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DOI：
10.1016/j.jnoncrysol.2013.12.023
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发表时间：
2014-10-01
影响因子：
3.5
通讯作者：
Plaisier, J. R.
中科院分区：
文献类型：
--
作者：
Cobourne, G.;Mountjoy, G.;Plaisier, J. R.
无定形碳酸钙(ACC)在海洋生物的生物矿化过程中起着关键作用。对镁稳定的ACC样品进行了中子和X射线衍射分析，该样品的镁钙比为0.05：1，每个CO3分子中有0.25个H2O分子。用经验势能结构修正方法建立了镁稳定的ACC模型，计算结果与实验衍射值吻合较好。该模型具有定义明确的CO3和H2O分子。Ca的平均配位数为7.4，由来自CO3分子的6.8个氧原子和来自H2O分子的0.6个氧原子组成。平均Ca-O键长为2.40埃。模型中钙的分布是均匀的，具有均匀分布的富钙网络，没有以前报道的ACC反向蒙特卡罗模型中的贫钙通道的证据。(C)2014爱思唯尔B.V.保留所有权利。
Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared with a Mg:Ca ratio of 0.05:1 and 0.25 H2O molecules per molecule of CO3. The empirical potential structure refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair agreement with the experimental diffraction data. The model has well-defined CO3 and H2O molecules. The average coordination number of Ca is 7.4 and is composed of 6.8 oxygen atoms from CO3 molecules and 0.6 oxygen atoms from H2O molecules. The average Ca-O bond length is 2.40 angstrom. The distribution of Ca in the model is homogeneous with a uniformly distributed Ca-rich network and no evidence of the Ca-poor channels as previously reported for a reverse Monte Carlo model of ACC. (C) 2014 Elsevier B.V. All rights reserved.