Abstract The plumbides CaTPb2 (T = Rh, Pd), EuTPb2 (T = Rh, Pd, Pt), SrTPb2 (T = Rh, Pd, Pt) and BaTPb2 (T = Pd, Pt) were obtained by direct reactions of the elements in sealed tantalum tubes in an induction furnace. The moisture sensitive polycrystalline samples were characterized by X-ray powder diffraction. They crystallize with the orthorhombic MgCuAl2-type structure, space group Cmcm. The structures of CaRhPb2 (a = 433.78(3), b = 1102.06(8), c = 798.43(6) pm, wR = 0.0285, 432 F2 values and 16 variables) and EuPdPb2 (a = 457.24(5), b = 1158.27(13), c = 775.73(8), wR = 0.0464, 464 F2 values and 16 variables) were refined from single crystal X-ray diffractometer data. The characteristic structural motif is the distorted tetrahedral substructure built up by the lead atoms with Pb–Pb distances of 326–327 pm in CaRhPb2 and of 315–345 pm in EuPdPb2. With increasing size of the alkaline earth (Eu) cation, the lead substructure becomes more anisotropic with a shift of the [TPb2] polyanions from three- to two-dimensional, leading to significantly increased moisture sensitivity. Temperature dependent magnetic susceptibility studies reveal Pauli paramagnetism for SrRhPb2, SrPtPb2, BaPdPb2 and BaPtPb2. EuRhPb2 and EuPdPb2 are Curie–Weiss paramagnets with stable divalent europium as is also evident from 151Eu Mössbauer spectra. EuRhPb2 is a ferromagnet with T C = 17.7(2) K, while EuPdPb2 orders antiferromagnetically at T N = 15.9 K. This is in agreement with the full magnetic hyperfine field splitting of the 151Eu Mössbauer spectra at T = 6 K.

中文翻译：

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三元铅垂体 ATPb2（A = Ca、Sr、Ba、Eu；T = Rh、Pd、Pt）与四面体连接的铅原子的扭曲的、与 lonsdaleite 相关的子结构

摘要 铅垂体CaTPb2 (T = Rh, Pd), EuTPb2 (T = Rh, Pd, Pt), SrTPb2 (T = Rh, Pd, Pt)和BaTPb2 (T = Pd, Pt)是通过元素的直接反应得到的。在感应炉中的密封钽管中。湿敏多晶样品通过 X 射线粉末衍射表征。它们以正交 MgCuAl2 型结构结晶，空间群为 Cmcm。CaRhPb2 (a = 433.78(3), b = 1102.06(8), c = 798.43(6) pm, wR = 0.0285, 432 F2值和16个变量)和EuPdPb2 (a = 457.24(5))的结构1158.27(13)、c = 775.73(8)、wR = 0.0464、464 个 F2 值和 16 个变量）是从单晶 X 射线衍射仪数据中提炼出来的。特征结构基序是由铅原子构成的扭曲四面体亚结构，在 CaRhPb2 中 Pb-Pb 距离为 326-327 pm，在 EuPdPb2 中为 315-345 pm。随着碱土金属 (Eu) 阳离子尺寸的增加，铅亚结构变得更加各向异性，[TPb2] 聚阴离子从三维向二维转变，导致水分敏感性显着增加。温度相关磁化率研究揭示了 SrRhPb2、SrPtPb2、BaPdPb2 和 BaPtPb2 的泡利顺磁性。EuRhPb2 和 EuPdPb2 是具有稳定二价铕的居里-魏斯顺磁体，从 151Eu Mössbauer 光谱也可以看出这一点。EuRhPb2 是 TC = 17.7(2) K 的铁磁体，而 EuPdPb2 在 TN = 15.9 K 处以反铁磁性排序。这与 151Eu Mössbauer 光谱在 T = 6 K 处的全磁超精细场分裂一致。随着 [TPb2] 聚阴离子从三维向二维的转变，铅亚结构变得更加各向异性，导致水分敏感性显着增加。温度相关磁化率研究揭示了 SrRhPb2、SrPtPb2、BaPdPb2 和 BaPtPb2 的泡利顺磁性。EuRhPb2 和 EuPdPb2 是具有稳定二价铕的居里-魏斯顺磁体，从 151Eu Mössbauer 光谱也可以看出这一点。EuRhPb2 是 TC = 17.7(2) K 的铁磁体，而 EuPdPb2 在 TN = 15.9 K 处以反铁磁性排序。这与 151Eu Mössbauer 光谱在 T = 6 K 处的全磁超精细场分裂一致。随着 [TPb2] 聚阴离子从三维向二维的转变，铅亚结构变得更加各向异性，导致水分敏感性显着增加。温度相关磁化率研究揭示了 SrRhPb2、SrPtPb2、BaPdPb2 和 BaPtPb2 的泡利顺磁性。EuRhPb2 和 EuPdPb2 是具有稳定二价铕的居里-魏斯顺磁体，从 151Eu Mössbauer 光谱也可以看出这一点。EuRhPb2 是 TC = 17.7(2) K 的铁磁体，而 EuPdPb2 在 TN = 15.9 K 处以反铁磁性排序。这与 151Eu Mössbauer 光谱在 T = 6 K 处的全磁超精细场分裂一致。EuRhPb2 和 EuPdPb2 是具有稳定二价铕的居里-魏斯顺磁体，从 151Eu Mössbauer 光谱也可以看出这一点。EuRhPb2 是 TC = 17.7(2) K 的铁磁体，而 EuPdPb2 在 TN = 15.9 K 处以反铁磁性排序。这与 151Eu Mössbauer 光谱在 T = 6 K 处的全磁超精细场分裂一致。EuRhPb2 和 EuPdPb2 是具有稳定二价铕的居里-魏斯顺磁体，从 151Eu Mössbauer 光谱也可以看出这一点。EuRhPb2 是 TC = 17.7(2) K 的铁磁体，而 EuPdPb2 在 TN = 15.9 K 处以反铁磁性排序。这与 151Eu Mössbauer 光谱在 T = 6 K 处的全磁超精细场分裂一致。