Raman spectroscopy and ab initio quantum chemical calculations of ion association behavior in calcium nitrate solution

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	Raman spectroscopy and ab initio quantum chemical calculations of ion association behavior in calcium nitrate solution
	Zhu, Fayan1 ; Zhou, Hongxia 2; Wang, Xiufang1 ; Zhou, Yongquan1 ; Liu, Hongyan1 ; Fang, Chunhui1 ; Fang, Yan1
	2018-05-01
发表期刊	JOURNAL OF RAMAN SPECTROSCOPY
卷号	49 期号:5 页码:852-861
关键词	Ab Initio Method Calcium Nitrate Component Analysis Ion Pair Raman Spectroscopy
摘要	In this work, microscopic Raman spectroscopy and component analysis were used to study a calcium nitrate solution with molar water-to-salt ratio (WSR) values of 4-320. The results showed that the symmetrical stretching vibration wavenumber of the nitrate ion (v(1)-NO3-) in the solution blue shifted from 1,048 to 1,053cm(-1), and the full width at half maximum increased from 9.7 to 11cm(-1) when the WSR was reduced from 320 to 4. The component analysis of v(1)-NO3- showed that the first concentration region was for WSR16.3. In this region, solvent-shared ion pairs (SIPs) were the main species, and contact ion pairs (CIPs) and free-hydrated ions were the secondary species. For 8.4WSR<16.3, the main species were CIPs; the amount of complex structures in this region increased rapidly, whereas the amount of SIPs decreased rapidly. For WSR<8.4, the main species were the complex structures, and the amount of CIPs and SIPs dropped rapidly. Ab initio quantum chemical calculations showed that the SIPs in the first concentration range were composed of 2 hexahydrate calcium ions and 1 nitrate ion that formed a shared ion pair, SIP-SIP. The calcium ions were directly bonded with water molecules, and the nitrate ions formed hydrogen bonds with the water molecules. In the second concentration region, the CIPs were each formed by 2 hydrated calcium ions and 1 nitrate ion via monodentate or bidentate coordination with a CIP-CIP structure. When the WSR was further reduced, a large number of the complex structures such as Comp5 and Comp6 formed in the solution, which were the complex structures [(H2O)(n)Ca2+(NO3-)Ca2+(H2O)(m)] clustered by C5 or C6.
语种	英语
引用统计
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/6697
专题	盐湖资源与化学实验室中国科学院青海盐湖研究所支撑部门
通讯作者	Fang, Chunhui
作者单位	1.Chinese Acad Sci, Inst Salt Lakes, Lab Salt Resources & Chem, Xining 810008, Qinghai, Peoples R China 2.Qinghai Univ, Mech Engn Coll, Xining 810001, Qinghai, Peoples R China
推荐引用方式 GB/T 7714	Zhu, Fayan,Zhou, Hongxia,Wang, Xiufang,et al. Raman spectroscopy and ab initio quantum chemical calculations of ion association behavior in calcium nitrate solution[J]. JOURNAL OF RAMAN SPECTROSCOPY,2018,49(5):852-861.
APA	Zhu, Fayan.,Zhou, Hongxia.,Wang, Xiufang.,Zhou, Yongquan.,Liu, Hongyan.,...&Fang, Yan.(2018).Raman spectroscopy and ab initio quantum chemical calculations of ion association behavior in calcium nitrate solution.JOURNAL OF RAMAN SPECTROSCOPY,49(5),852-861.
MLA	Zhu, Fayan,et al."Raman spectroscopy and ab initio quantum chemical calculations of ion association behavior in calcium nitrate solution".JOURNAL OF RAMAN SPECTROSCOPY 49.5(2018):852-861.