Abstract Calcium carbonates (calcite and aragonite) were synthesized at 10–40 °C to understand the partitioning behavior of sodium during the mineralization of marine organisms. The role of organic ligands (acetic acid) in sodium partitioning into calcium carbonates was also investigated. The partitioning coefficient of sodium, defined as Kd = (Na/Ca)CaCO3/(Na/Ca)solvent, was higher for aragonite than for calcite. The Kd values associated with organic-free solvents decreased with increasing temperature. In contrast, for solvents containing acetic acid, Kd increased with increasing temperature. The K-edge X-ray absorption near edge structure (XANES) measurement of Na suggests that Na substitutes the Ca sites in CaCO3 crystals, regardless of the solvent containing organic ligands. The partitioning behavior associated with the solvent containing acetic acid seems to represent the natural mineralization process in the calcification fluid, which contains a substantial amount of carboxylate. The temperature dependence of Kd was especially clear for aragonite produced from the solvent containing acetic acid. Our findings may help to understand the selection and regulation of crystal polymorphs by marine species in different localities and in different geological era.

中文翻译：

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将钠分配到 10–40 °C 合成的碳酸钙中：有机配体和温度的影响

摘要 碳酸钙（方解石和文石）在 10-40 °C 下合成，以了解钠在海洋生物矿化过程中的分配行为。还研究了有机配体（乙酸）在钠分配到碳酸钙中的作用。钠的分配系数，定义为 Kd = (Na/Ca)CaCO3/(Na/Ca) 溶剂，文石高于方解石。与无有机溶剂相关的 Kd 值随温度升高而降低。相反，对于含有乙酸的溶剂，Kd 随温度升高而增加。Na 的 K 边 X 射线吸收近边结构 (XANES) 测量表明，Na 取代了 CaCO3 晶体中的 Ca 位点，而与含有有机配体的溶剂无关。与含有乙酸的溶剂相关的分配行为似乎代表了钙化流体中的自然矿化过程，其中包含大量的羧酸盐​​。对于由含有乙酸的溶剂生产的文石，Kd 的温度依赖性尤其明显。我们的研究结果可能有助于了解不同地点和不同地质时代海洋物种对晶体多晶型的选择和调控。