铝硅酸盐熔体微结构单元的探讨     

蒋国昌吴永全  尤静林侯怀宇 陈辉 《岩石学报》2004,20(3):753-758

本文是一篇综述，讨论在熔融铝硅酸盐和铝酸盐中Al的两性行为。这是7台金学和岩石学中一个至今尚无可靠结论的问题。作者认为：每个四配位的Ala都含一个配位键，例如Al—O(^Ca Si)或Al—O(^Ca Al)。相应的非桥氧Onb并没有消失，而是变成了三价氧离子。碱性Alb能否出现取决于该体系的酸碱平衡。构筑硅酸盐的键合结构模型时，作者建议用5种Si-O四面体(Qn)作为微结构单元。即，用它们的相对量和微观化学位描述其宏观物性(如组元活度)。为了沟通铝硅酸盐的微观结构与宏观物性，仍可用5种Qn作为微结构单元。其中所含Ala的影响用各种Qn微观化学位的相应变化来反映。对于铝酸盐，建议用Ala-O四面体(Tn)作为微结构单元。  相似文献   

Polysomatism and modules of gehlenite composition and structure in the Hanic phase (Ca5Al6MgSiO17)     

I. Dódony  P. R. Buseck 《Physics and Chemistry of Minerals》2001,28(6):428-434

 Discrete, well-ordered, single-phase crystals (the Hanic phase) form when powders the bulk composition of Ca₅Al₆MgSiO₁₇ are allowed to react in the absence of a melt. If, on the other hand, either the powders or crystals of Ca₅Al₆MgSiO₁₇ are molten and then cooled, complex intergrowths form. These intergrowths consist of modules having the composition and structure of Ca₃Al₄MgO₁₀ and gehlenite (Ca₂Al₂SiO₇), forming a polysomatic series in which the modules occur in varied proportions. High-resolution transmission electron microscope (HRTEM) images reveal the details of these intergrowths. Mass balance is achieved by the formation of this polysomatic series together with Mg-substituted mayenite (Ca_12−xMg_xAl₁₄O₃₃). The tetrahedral sheets in gehlenite have close structural similarities to those of Ca₅Al₆O₁₄. Based on our HRTEM images, we hypothesize chemical substitutions between gehlenite and Ca₅Al₆O₁₄, resulting in gehlenite-like modules that are depleted in Si and correspondingly enriched in Al and Ca. Received: 2 August 2000 / Accepted: 18 January 2001  相似文献