The silicides ScT 2Si2 (T = Ru, Rh, Os) were synthesized by arc-melting of the elements and subsequent annealing in sealed silica ampoules. They crystallize with the rarely observed HfFe2Si2 type structure, space group Pbcm. The structures of ScRu2Si2 (a = 761.64(4), b = 730.70(6), c = 521.07(6) pm, wR = 0.0314, 633 F 2 values, 31 variables) and ScOs2Si2 (a = 771.10(8), b = 736.68(7), c = 521.88(5) pm, wR = 0.0479, 623 F 2 values, 31 variables) were refined from single crystal X-ray diffractometer data. The refinements showed small degrees of Ru/Si respectively Os/Si mixing on one 4c site, leading to the refined compositions ScRu1.96(1)Si2.04(1) and ScOs1.91(1)Si2.09(1). The monomeric building units in both structures are two slightly distorted, crystallographically independent RuSi5 respectively OsSi5 square pyramids, which are condensed via common edges. The resulting densely packed [Ru2Si2] and [Os2Si2] networks leave voids for the scandium atoms with coordination number 18: Sc@Si8Ru8Sc2 and Sc@Si8Os8Sc2. Temperature dependent magnetic susceptibility measurements of ScRu2Si2 and ScOs2Si2 indicate Pauli paramagnetism. Solid-state 29Si and 45Sc static and MAS NMR spectroscopy reveal significant Knight shifts and a strong influence of the T/Si mixing on the experimental NMR line shapes. A larger overall 29Si magnetic shift for ScRu2Si2 compared to ScOs2Si2, although with a negative sign for one of the 29Si resonances, suggests stronger paramagnetic effects for ScRu2Si2, in agreement with the magnetic susceptibility measurements.

中文翻译：

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HfFe2Si2 型硅化物 ScT 2Si2 (T = Ru、Rh、Os) – 结构和固态 29Si/45Sc NMR 光谱

硅化物Sc时间 2硅2（时间= Ru、Rh、Os）通过元素的电弧熔化和随后在密封二氧化硅安瓿中的退火来合成。它们与很少观察到的 HfFe 一起结晶2硅2类型结构、空间群铅。ScRu 的结构2硅2（A= 761.64(4),乙= 730.70(6),C= 521.07(6) 下午，w右= 0.0314, 633F 2值，31 个变量）和 ScO2硅2（A= 771.10(8),乙= 736.68(7),C= 521.88(5) 下午，w右= 0.0479, 623F 2值（31 个变量）是根据单晶 X 射线衍射仪数据精炼的。细化结果表明，Ru/Si 和 Os/Si 在其中一个 4 上有小程度的混合。C站点，导致精制组合物 ScRu1.96(1)硅2.04(1)和氧化钪1.91(1)硅2.09(1)。两种结构中的单体结构单元都是两个稍微扭曲、晶体学独立的 RuSi5分别为 OsSi5方形金字塔，通过公共边缘压缩而成。由此产生的密集的[Ru2硅2] 和 [Os2硅2] 网络为配位数为 18 的钪原子留下空隙：Sc@Si8茹8钪2和Sc@Si8操作系统8钪2。ScRu 的温度依赖性磁化率测量2硅2和氧化钪2硅2表明泡利顺磁性。固体状态29硅和45Sc 静态和 MAS NMR 光谱揭示了显着的奈特位移和时间/Si 混合对实验 NMR 线形状的影响。整体更大29ScRu 的 Si 磁位移2硅2与 ScO 相比2硅2，尽管其中之一带有负号29Si 共振表明 ScRu 具有更强的顺磁效应2硅2，与磁化率测量一致。