摘要
利用原位高温拉曼光谱技术对Na_2MoO_4·2H_2O(NMHO)晶体的脱水、相变以及熔融过程中微结构变化和分子振动特性进行了研究。结果显示在363 K,正交NMHO晶体脱水形成对称性更高的立方α-NMO(Na_2MoO_4)晶体;随着温度升高至熔点,α-NMO晶体经历了如下相变:α→β→γ→δ,分析了相变过程中温度对孤立的[MoO_4]_(2-)中Mo-O键的对称伸缩振动波数的作用,进而获得其平均键长以及对称性的变化过程;结合密度泛函理论对已知晶型的NMHO,α-NMO及γ-NMO晶体进行了拉曼光谱的计算模拟,并对其振动模式进行了归属;采用量子化学从头计算方法研究了NMO熔体中[MoO_4]^(2-)的团簇类型。
In-situ high temperature Raman spectroscopy was used to study the variations of micro-structure changes and molecular vibrational properties of Na2MoO4·2H2O (NMHO) crystal during dehydration, phase transformation and melting process. The results showed that the orthorhombic NMHO crystal dehydrates to form a more symmetrical cubic α-NMO (Na2MoO4) crystal at 363 K. As the temperature increases,α-NMO crystal undergoes the following phase transitions:α→β→γ→δ before melting. The effect of temperature on the wavenumber of Mo-O symmetric stretching vibrational mode of the isolated [MoO4]2- during phase transformation was analyzed. Furthermore, temperature dependent average bond length and symmetry were derived. The simulated Raman spectra of known NMHO,α- and γ-NMO crystals were performed based on DFT and their vibrational modes were then assigned. The configurations of [MoO4]2- clusters in the NMO melt were studied by the quantum chemical ab initio calculation method.
作者
丁雅妮
尤静林
王敏
Lu Liming
王建
曹培明
徐琰东
DING Ya-Ni;YOU Jing-Lin;WANG Min;LU Liming;WANG Jian;CAO Pei-Ming;XU Yan-Dong(State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;CSIRO Mineral Resources, Technology Court, Pullenvale, Queensland 4069, Australia)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2019年第5期803-811,共9页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21773152)
111引智项目(No.D17002)
上海市科学技术委员会项目(No.12520709200)
省部共建高品质特殊钢冶金与制备国家重点实验室开放课题(No.SKLASS2015-01
SKLASS2017-02)
省部共建高品质特殊钢冶金与制备国家重点实验室自主课题(No.SKLASS2016-Z01)
科技部中央引导基金资助项目(No.YDZX20173100001316)资助
