浓氯化钙水溶液中高配位Ca-Cl离子团簇:分子动力学模拟研究
High Coordinated Ca(II) Chloro Ion Clusters in the Concentrated CaCl2 Aqueous Solution:A Molecular Dynamics Simulation Study 
投稿时间:2019-03-08  修订日期:2019-04-10
DOI:10.12119/j.yhyj.202003004
中文关键词:  氯化钙  离子团簇  缔合  温度  分子动力学模拟
英文关键词:Calcium chloride  Association  Ion cluster  Temperature  Molecular dynamics simulation
基金项目:湖南省教育厅一般项目(17C1639);湖南省自然科学基金青年项目(2018JJ3883);国家自然科学基金青年基金(51704338)
作者单位E-mail
王语林 中国石油兰州化工研究中心,甘肃兰州 730060 wangyulinhuda@163.com 
唐剑峰 中南林业科技大学理学院,湖南长沙 410004  
张宁 中南林业科技大学理学院,湖南长沙 410004  
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中文摘要:
      采用分子动力学(MD)模拟研究了5.55 mol·kg-1氯化钙溶液的微观结构特征,尤其是溶液中高配位Ca-Cl离子团簇的结构与性质,探究了温度对于高配位Ca-Cl离子团簇的影响。结果显示,5.55 mol·kg-1氯化钙溶液中,除形成+、[CaCl2]0离子对外,还存在一些高配位[CaClx]2-x (x=3~6)离子团簇。高配位[CaClx]2-x (x=3~6)离子团簇在5.55 mol·kg-1氯化钙溶液中介稳存在,易解离或进一步缔合形成更大Ca-Cl离子团簇,这可能与溶液中大量未完全水合Ca2+对高配位[CaClx]2-x (x=3~6)离子团簇水壳层的扰动破坏有关。温度升高,氯化钙溶液中Ca-Cl离子缔合增强,但高配位Ca-Cl离子团簇的平均存在时间(tav)减小,这表示高温下溶液中Ca-Cl离子团簇频繁地解离与缔合,离子团聚趋势更为显著。本工作观测到的高配位[CaClx]2-x (x=3~6)离子团簇可能是浓氯化钙溶液Ca-Cl离子缔合过程中一种热力学不稳定结构,但这些高配位Ca-Cl离子团簇的形成可能对溶液结晶及相关化学过程产生不利影响。
英文摘要:
      : Molecular dynamics simulation was employed to investigate the structural characteristics of 5.55 mol·kg-1 CaCl2 solution,especially the high\|coordinated Ca\|Cl ion clusters observed in the solution. The results show that there may be some highly coordinated [CaClx]2-x (x=3~6) ion clusters formed in 5.55 mol·kg-1 CaCl2 solution,apart from the + and [CaCl2]0 ion pairs. The highly coordinated Ca\|Cl ion clusters remain meta-stable in 5.55 mol·kg-1 CaCl2 solution and easily disassociate into smaller structures or associate with other ions to form the larger Ca\|Cl ion clusters,which may be related to the disturbing damage of the numerous Ca2+, without adequate hydration,to the outer shells of the high-coordinated Ca\|Cl ion clusters in the concentrated CaCl2 solution. As the temperature rises,Ca-Cl ion association increases in 5.55 mol·kg-1 CaCl2 solution,but the average lifetime (tav) of the [CaClx]2-x (x=3~6) ion clusters decreases,indicating that at elevated temperature the Ca-Cl ion clusters frequently disassociate and associate,and the tendency of ionic aggregation in the solution is more pronounced. The highly coordinated [CaClx]2-x(x=3~6) ion clusters observed in this work may be a thermodynamically unstable structure during the ion association in 5.55 mol·kg-1 CaCl2 solution,but the formation of the high\|coordinated Ca\|Cl ion clusters can exert some negative influences on the crystallization of the CaCl2 solution and other related chemical processes.
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