Han Huijun, Park Yunjae, Kim Yohan, Ding Feng, Shin Hyung-Joon
Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.
Nat Commun. 2024 Mar 16;15(1):2401. doi: 10.1038/s41467-024-46704-y.
Interactions between monatomic ions and water molecules are fundamental to understanding the hydration of complex polyatomic ions and ionic process. Among the simplest and well-established ion-related reactions is dissolution of salt in water, which is an endothermic process requiring an increase in entropy. Extensive efforts have been made to date; however, most studies at single-ion level have been limited to theoretical approaches. Here, we demonstrate the salt dissolution process by manipulating a single water molecule at an under-coordinated site of a sodium chloride film. Manipulation of molecule in a controlled manner enables us to understand ion-water interaction as well as dynamics of water molecules at NaCl interfaces, which are responsible for the selective dissolution of anions. The water dipole polarizes the anion in the NaCl ionic crystal, resulting in strong anion-water interaction and weakening of the ionic bonds. Our results provide insights into a simple but important elementary step of the single-ion chemistry, which may be useful in ion-related sciences and technologies.
单原子离子与水分子之间的相互作用是理解复杂多原子离子水合作用及离子过程的基础。在最简单且已确立的与离子相关的反应中，盐在水中的溶解是其中之一，这是一个需要熵增加的吸热过程。迄今为止人们已经付出了大量努力；然而，大多数单离子水平的研究都局限于理论方法。在此，我们通过在氯化钠薄膜的低配位位点操纵单个水分子来演示盐的溶解过程。以可控方式对分子进行操纵使我们能够理解离子与水的相互作用以及氯化钠界面处水分子的动力学，这些动力学负责阴离子的选择性溶解。水偶极使氯化钠离子晶体中的阴离子极化，导致强烈的阴离子 - 水相互作用并削弱离子键。我们的结果为单离子化学中一个简单但重要的基本步骤提供了见解，这可能在与离子相关的科学和技术中有用。
