Department of Chemistry, Nanochemistry Research Institute, Curtin University, PO Box U1987, Perth, Western Australia 6845, Australia.
Nat Commun. 2011 Dec 20;2:590. doi: 10.1038/ncomms1604.
Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide in water with calcium ions. Through biomineralization, organisms can harness and control this process to form various functional materials that can act as anything from shells through to lenses. The early stages of calcium carbonate formation have recently attracted attention as stable prenucleation clusters have been observed, contrary to classical models. Here we show, using computer simulations combined with the analysis of experimental data, that these mineral clusters are made of an ionic polymer, composed of alternating calcium and carbonate ions, with a dynamic topology consisting of chains, branches and rings. The existence of a disordered, flexible and strongly hydrated precursor provides a basis for explaining the formation of other liquid-like amorphous states of calcium carbonate, in addition to the non-classical behaviour during growth of amorphous calcium carbonate.
碳酸钙是一种丰富的物质,可以通过水中溶解的二氧化碳与钙离子反应生成几种矿物形式。通过生物矿化,生物体可以利用和控制这个过程,形成各种功能材料,这些材料可以作为从壳到透镜的各种物质。碳酸钙形成的早期阶段最近引起了人们的注意,因为已经观察到稳定的预成核簇,这与经典模型相反。在这里,我们使用计算机模拟结合实验数据分析表明,这些矿物簇由交替的钙和碳酸盐离子组成的离子聚合物构成,具有由链、分支和环组成的动态拓扑结构。无序、灵活和高度水合的前体的存在为解释除非经典行为外,碳酸钙的其他类似液体的无定形状态的形成提供了基础。