Structural investigations on two typical lithium germanate melts by in situ Raman spectroscopy and density functional theory calculations

doi:10.1039/c9ce01512d

	Structural investigations on two typical lithium germanate melts by in situ Raman spectroscopy and density functional theory calculations
	Wan, Songming 3; Zhang, Shujie 1,3; Gong, Xiaoye 2; Zeng, Yu 1,3; Jiang, Shengjie 1,3; You, Jinglin 2
刊名	CRYSTENGCOMM
	2020-01-28
卷号	22
ISSN号	1466-8033
DOI	10.1039/c9ce01512d
通讯作者	Wan, Songming(smwan@aiofm.ac.cn)
英文摘要	Deeply understanding the physical and chemical properties of a melt requires an accurate description of its structure. In this paper, we investigated the structures of Li4GeO4 and Li6Ge2O7 melts which are of interest for growing germanate functional crystals. The structural changes of polycrystalline Li4GeO4 and Li6Ge2O7 from room temperature to their melting temperatures were monitored by Raman spectroscopy and analyzed by density functional theory (DFT) and factor group theory (FGT) calculations. A striking spectral change was observed for polycrystalline Li4GeO4, which is due to the orthorhombic-to-monoclinic phase transition and the Li+ disorder induced by the phase transition. Spectral similarity between monoclinic Li4GeO4 and its corresponding melt indicates that the anion motif of the Li4GeO4 melt is the GeO(4)(4-)tetrahedron. The Li6Ge2O7 crystal has 180 lattice phonons (45A(g) + 45A(u) + 45B(g) + 45B(u)) at the centre of the Brillouin zone, including 90 Raman-active phonons (45A(g) + 45B(g)). All the Raman-active bands were assigned by DFT calculations. The Raman spectrum of polycrystalline Li6Ge2O7 varies smoothly and continuously in the heating/melting process, indicating that the Ge2O76- anion groups in the crystal are preserved in the melt. The disproportionation reaction that often occurs in silicate melts was not found in the Li6Ge2O7 melt. A nucleophilic substitution reaction is proposed
资助项目	National Natural Science Foundation of China[51372246] ; National Natural Science Foundation of China[21773152] ; Open Project of State Key Laboratory of Advanced Special Steel, Shanghai University
WOS关键词	CRYSTAL-STRUCTURE ; SCATTERING ; LIQUID ; PHONONS ; LI2SIO3 ; SPECTRA ; BINARY ; GROWTH ; OXIDES
WOS研究方向	Chemistry ; Crystallography
语种	英语
出版者	ROYAL SOC CHEMISTRY
WOS记录号	WOS:000521652900012
资助机构	National Natural Science Foundation of China ; Open Project of State Key Laboratory of Advanced Special Steel, Shanghai University
内容类型	期刊论文
源URL	[http://ir.hfcas.ac.cn:8080/handle/334002/103483]
专题	中国科学院合肥物质科学研究院
通讯作者	Wan, Songming
作者单位	1.Univ Sci & Technol China, Hefei 230026, Peoples R China 2.Shanghai Univ, Sch Mat Sci & Engn, Shanghai 200444, Peoples R China 3.Chinese Acad Sci, Anhui Inst Opt & Fine Mech, Anhui Key Lab Photon Devices & Mat, Hefei 230031, Peoples R China
推荐引用方式 GB/T 7714	Wan, Songming,Zhang, Shujie,Gong, Xiaoye,et al. Structural investigations on two typical lithium germanate melts by in situ Raman spectroscopy and density functional theory calculations[J]. CRYSTENGCOMM,2020,22.
APA	Wan, Songming,Zhang, Shujie,Gong, Xiaoye,Zeng, Yu,Jiang, Shengjie,&You, Jinglin.(2020).Structural investigations on two typical lithium germanate melts by in situ Raman spectroscopy and density functional theory calculations.CRYSTENGCOMM,22.
MLA	Wan, Songming,et al."Structural investigations on two typical lithium germanate melts by in situ Raman spectroscopy and density functional theory calculations".CRYSTENGCOMM 22(2020).