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首页> 外文期刊>Zeitschrift fur Anorganische und Allgemeine Chemie >The sialons MLn[Si4-xAlxOxN7-x] with M = Eu, Sr, Ba and Ln = Ho-Yb - Twelve substitution variants with the MYb[Si4N7] structure type
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The sialons MLn[Si4-xAlxOxN7-x] with M = Eu, Sr, Ba and Ln = Ho-Yb - Twelve substitution variants with the MYb[Si4N7] structure type

机译：唾液MLn [Si4-xAlxOxN7-x]，M = Eu，Sr，Ba和Ln = Ho-Yb-十二个具有MYb [Si4N7]结构类型的取代变体

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摘要

The oxonitridoalumosilicates (so-called sialons) MLn[Si4-xAlxOxN7-x] with M = Eu, Sr, Ba and Ln = Ho, Er, Tm, Yb were obtained by the reaction of the respective lanthanoid metal, the alkaline earth carbonates or europium carbonate, resp., AlN, "Si(NH)(2)" and MCl2 as a flux in a radiofrequency furnace at temperatures around 2100 degrees C. The compounds MLn[Si4-xAlxOxN7-x] are relevant for the investigation of substitutional effects on the materials properties due to their ability of tolerating a comparatively large phase width up to x approximate to 2.0(5). The crystal structures of the twelve compounds were refined from X-ray single crystal data and X-ray powder data and are found to be isotypic to the MYb[Si4N7] structure type. The compounds crystallize in space group P6(3)mc (no. 186, hexagonal) and are made up of chains of so-called starlike units [N-[4](SiN3)(4)] or [N-[4]]((Si,Al)-(O,N)(3))(4)], respectively. These units are formed by four (Si,Al)(N/O)(4) tetrahedra sharing a common central nitrogen atom. The structure refinement was performed utilizing an O/N-distribution model according to Paulings rules, i.e. nitrogen was positioned on the fourfold bridging site and nitrogen and oxygen were distributed equally on both of the two-fold bridging sites, resulting in charge neutrality of the compound. The Si and Al atoms were distributed equally on their two crystallographic sites, referring to their elemental proportion in the compound, due to being poorly distinguishable by X-ray methods. The chemical compositions of the compounds were derived from electron probe micro analyses (EPMA).
机译：通过相应的镧系金属，碱土金属碳酸盐或碳酸p，分别为AlN，“ Si（NH）（2）”和MCl2作为射频炉中2100摄氏度左右温度下的助熔剂。化合物MLn [Si4-xAlxOxN7-x]与取代基的研究有关对材料性能的影响，是因为它们能够承受较大的相宽，直到x接近2.0（5）。从X射线单晶数据和X射线粉末数据中精制了这12种化合物的晶体结构，发现它们与MYb [Si4N7]结构类型同型。这些化合物在空间群P6（3）mc（第186号，六边形）中结晶，由所谓的星形单元[N- [4]（SiN3）（4）]或[N- [4]的链组成]（（Si，Al）-（O，N）（3））（4）]。这些单元由共享共同中心氮原子的四个（Si，Al）（N / O）（4）四面体形成。根据Paulings规则，使用O / N分布模型对结构进行细化，即，将氮置于四重桥接位点上，将氮和氧均等地分布在两重桥接位点上，从而使电荷中性。复合。硅和铝原子由于在X射线法中难以区分，因此在化合物的元素中所占的比例均等地分布在其两个晶体学位置上。化合物的化学成分来自电子探针显微分析（EPMA）。

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