The role of Mg2+ as an impurity in calcite growth
The role of Mg2+ as an impurity in calcite growth
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DOI：
10.1126/science.290.5494.1134
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发表时间：
2000-11-10
期刊：
影响因子：
56.9
通讯作者：
De Yoreo, JJ
中科院分区：
文献类型：
--
作者：
Davis, KJ;Dove, PM;De Yoreo, JJ
镁是CaCO3矿化的关键决定因素；然而，宏观观察未能提供镁如何改变碳酸盐生长的清晰物理理解。通过分子尺度上镁对方解石形成的热力学和动力学控制，利用原子力显微镜分析了镁对方解石的抑制机理。直接测量的步速与标准杂质模型的比较表明，通过镁掺入提高矿物溶解度抑制了方解石的生长。方解石生长螺旋的阶地宽度测量结果与镁掺入导致的有效过饱和度降低一致。从阶梯动力学的微观观察确定的Ca1-xMgxCO3溶解度因此可以与宏观测量相联系。
Magnesium is a key determinant in CaCO3 mineralization; however, macroscopic observations have failed to provide a clear physical understanding of how magnesium modifies carbonate growth. Atomic force microscopy was used to resolve the mechanism of calcite inhibition by magnesium through molecular-scale determination of the thermodynamic and kinetic controls of magnesium on calcite formation. Comparison of directly measured step velocities to standard impurity models demonstrated that enhanced mineral solubility through magnesium incorporation inhibited calcite growth. Terrace width measurements on calcite growth spirals were consistent with a decrease in effective supersaturation due to magnesium incorporation. Ca1-xMgxCO3 solubilities determined from microscopic observations of step dynamics can thus be Linked to macroscopic measurements.