Crystal chemical studies on incommensurately modulated mullite

不通约调制莫来石的晶体化学研究

• 批准号: 186441782
• 负责人: Professor Dr. Reinhard X. Fischer
• 金额: --
• 依托单位: Fachbereich 05: Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/186441782?language=en
• 关键词: Crystal; chemical; studies; incommensurately; modulated

The crystal structure of mullite (2:1-mullite, i.e. 2Al2O3 . SiO2, Al4.8Si1.2O9.6, Z=1) is characterized by chains of edge-sharing AlO6 octahedra linked by double chains of (Al,Si)O4 tetrahedra affected by vacancies on the bridging oxygen position. Angel et al. 1991 (Amer. Mineral. 76, 332-342) studied the incommensurately modulated structure with the conclusion that the cations and oxygen vacancies are partially ordered in mullite. However, they used a mullite single crystal of low quality for their studies, and thus were not able to provide the information required to fully understand the real structure of mullite. It is the aim of this study to gain further understanding by crystal structure analysis in higher dimensional space based on neutron diffraction data of Bragg and super-structure reflections. A clear inclusion-free Czochralski-grown mullite single crystal is available for that purpose. The experimental works will be accompanied by oxygen vacancy modeling calculations. The findings of the ordering patterns will be correlated with the lattice parameters and properties of mullite like elasticity and thermal expansion.

mullite的晶体结构（2：1-毛利石，即2al2o3。Sio2，al4.8Si1.2O9.6，z = 1）的特征是边缘共享Alo6 oct oct of（al，si）o4四面体受到桥接氧气位置的空缺影响。 Angel等。 1991（Amer。Minerer。76，332-342）研究了不可兑换的结构，得出的结论是，阳离子和氧空位是在Mullite中部分排序的。但是，他们在研究中使用了低质量的mullite单晶，因此无法提供充分理解Mullite实际结构所需的信息。这项研究的目的是根据布拉格和超结构反射的中子衍射数据在更高维空间中通过晶体结构分析获得进一步的理解。为此，可以使用清晰的无包含Czochralski种植的Mullite单晶。实验工作将伴随氧气空缺模型计算。排序模式的发现将与晶格参数和弹性和热膨胀的晶格参数和性质相关。

项目成果

Mullite and mullite-type crystal structures

莫来石和莫来石型晶体结构

• DOI: 10.3139/146.110713
• 发表时间: 2012
• 期刊: International Journal of Materials Research
• 影响因子: 0.8
• 作者: R.X. Fischer;A. Gaede-Köhler;J. Birkenstock;H. Schneider
• 通讯作者: H. Schneider