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本文测定了Na4GeO4、Na2GeO3、Na2Ge4O9和Na4Ge9O20等晶体从273K到1413K升温及熔体的拉曼光谱,结合分析金红石型GeO2的相关结构和光谱,研究了其微结构单元在升温过程中的变化、熔体中的形态和锗的氧配位数及其温致变化。Na4GeO4和Na2GeO3晶体结构单元为GeO4四面体,在升温过程及其熔体中锗维持四配位。Na2Ge4O9和Na4Ge9O20晶体结构单元为GeO4四面体和GeO6八面体共存,升温过程中,GeO6八面体将发生结构转变,在熔融状态全部转变为GeO4四面体,并产生与钠离子等摩尔分数的非桥氧,在熔体中锗的氧配位数为4。研究还表明,桥氧的对称弯曲振动模可以反映不同微结构单元间的连接,并且随着温致结构的变化而产生特征性的变化。
In this paper, Raman spectra of Na4GeO4, Na2GeO3, Na2Ge4O9 and Na4Ge9O20 from 273K to 1413K were measured and the Raman spectra of the melt were analyzed. The changes of microstructure units during heating were investigated by analyzing the related structures and spectra of rutile GeO2. The shape of the body and the oxygen coordination number of germanium and its temperature change. The crystal structure unit of Na4GeO4 and Na2GeO3 is GeO4 tetrahedron, and germanium maintains tetrahedral coordination in the temperature rising process and its melt. The crystal units of Na2Ge4O9 and Na4Ge9O20 coexist with GeO4 tetrahedrons and GeO6 octahedrons. During the heating process, the GeO6 octahedrons will undergo structural transformation, all of which will transform into GeO4 tetrahedrons in the molten state and produce non-bridging oxygen with equimolar fraction of sodium ions , Germanium in the melt oxygen coordination number of 4. The study also shows that the symmetric flexural vibration modes of bridging oxygen can reflect the connection between different microstructural units and produce a characteristic change with the change of thermo-induced structure.