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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Sc5Pd4Si6 - crystal structure and Si-29/Sc-45 solid state MAS NMR spectroscopic investigations
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Sc5Pd4Si6 - crystal structure and Si-29/Sc-45 solid state MAS NMR spectroscopic investigations

机译：SC5PD4SI6 - 晶体结构和Si-29 / SC-45固态MAS NMR光谱研究

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The silicide Sc5Pd4Si6 was synthesized from the elements by arc-melting. Its structure was refined from single crystal X-ray diffractometer data: Immm, Li5Cu3.75P6 type, a = 397.12(6), b = 945.4(1), c = 1314.4(2) pm, wR(2) = 0.0245, 578 F-2 values and 29 parameters. The palladium atoms have slightly distorted tetrahedral silicon coordination and a condensation of these PdSi4 tetrahedra leads to a two-dimensional substructure which is condensed via Si-2 pairs (234 pm Si-Si), forming the [Pd4Si6](-) polyanionic network. The Sc5Pd4Si6 structure contains three crystallographically independent scandium sites with coordinations Sc1@Pd4Si8Sc6, Sc2@Pd6Si6Sc3 and Sc3@Pd4Si6Sc4. Sc5Pd4Si6 is a Pauli paramagnet with a low susceptibility of 2.9(5) x 10(-5) emu mol(-1) at room temperature. The Si-29 MAS-NMR spectrum confirms the presence of two crystallographically distinct sites in a 2:1 ratio. Likewise, the three crystallographic scandium sites are well-differentiated by three Sc-45 MAS NMR signals in the expected 2:2:1 ratio. Unambiguous assignments could be made based on the comparison of the nuclear electric quadrupolar coupling parameters with predicted values from WIEN2k calculations.
机译：通过电弧熔化从元件合成硅化物SC5PD4SI6。其结构由单晶X射线衍射仪数据进行精制：IMMM，Li5Cu3.75P6型，A = 397.12（6），B = 945.4（1），C = 1314.4（2）PM，WR（2）= 0.0245,578 F-2值和29个参数。钯原子具有略微扭曲的四面体硅协调，并且这些PDSi4四氢的冷凝导致二维子结构，其通过Si-2对（234pm Si-Si）缩合，形成[Pd4Si6]（ - ）的多阴离子网络。 SC5PD4SI6结构包含三个具有协调SC1 @ PD4SI8SC6，SC2 @ PD6SI6SC3和SC3 @ PD4SI6SC4的三个晶体独立的钪位点。 SC5PD4SI6是保利帕拉尼蛋白，在室温下具有低敏感性为2.9（5）×10（-5）EMUMOL（-1）。 Si-29MAS-NMR光谱证实了2：1比例的两个晶形上不同的位点。同样，三个晶体钪位点在预期的2：2：1的比例中通过三种SC-45MAS NMR信号进行良好分化。可以基于来自Wien2K计算的预测值的核电四桥耦合参数的比较来进行明确的分配。

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