Correlations of Crystal and Electronic Structure via NMR and X-ray Photoelectron Spectroscopies in the RETMAl2 (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; TM = Ni, Pd, Pt) Series.
Correlations of Crystal and Electronic Structure via NMR and X-ray Photoelectron Spectroscopies in the RETMAl2 (RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu; TM = Ni, Pd, Pt) Series.
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通过 NMR 和 X 射线光电子能谱分析 RETMAl2（RE = Sc、Y、La-Nd、Sm、Gd-Tm、Lu；TM = Ni、Pd、Pt）系列中晶体和电子结构的相关性。
DOI：
10.1021/acs.inorgchem.9b00648
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发表时间：
2019
影响因子：
4.6
通讯作者：
O. Janka
中科院分区：
文献类型：
--
作者：
Mathis Radzieowski;F. Stegemann;C. Doerenkamp;S. Matar;H. Eckert;C. Dosche;G. Wittstock;O. Janka
采用电弧熔合法制备了35种金属间铝化合物，并用粉末x射线衍射对其进行了表征。其中15例以前曾报道过；然而，没有详细的财产调查。RETMAl2（稀土金属RE = Sc， Y, La-Nd, Sm, Gd-Tm, Lu）系列化合物与过渡金属TM = Ni, Pd， Pt在结构上呈正交MgCuAl2型结构（Cmcm, oC16, fc2）。对YNiAl2、LaNiAl2、YPdAl2、ScPtAl2和YPtAl2进行了单晶x射线衍射研究。TM和Al原子形成[TMAl2]δ-聚阴离子，RE原子驻留在骨架内的空腔中。Sc， Y， La和Lu化合物表现出保利顺磁性，与所有原子都是闭合壳层一致，而其他RETMAl2化合物在低温下表现出顺磁性和磁有序，与RE原子的开壳三价氧化态一致。对保利顺磁样品进行了固态27Al核磁共振研究，所有样品都显示只有一个中心转变，符合各自原子的一个晶体学位点。观测到的四极耦合常数和电场梯度不对称参数与密度泛函理论计算值吻合较好。各向同性共振位移主要由费米边与s-传导电子密度的费米接触相互作用（Knight位移）控制。成键特性反映了所考虑的金属间化合物族的电子态密度和晶体化学。奈特位移和四极耦合常数都可以基于特定元素的增量来预测。
A total of 35 intermetallic aluminum compounds have been synthesized from the elements via arc melting and characterized by powder X-ray diffraction. A total of 15 of them have been previously reported; however, detailed property investigations were missing. Compounds of the RETMAl2 (rare earth metal RE = Sc, Y, La-Nd, Sm, Gd-Tm, Lu) series with transition metal TM = Ni, Pd, and Pt crystallize isostructurally in the orthorhombic MgCuAl2 type structure ( Cmcm, oC16, fc2). Single-crystal X-ray diffraction investigations were conducted on YNiAl2, LaNiAl2, YPdAl2, ScPtAl2, and YPtAl2. The TM and Al atoms form a [TMAl2]δ- polyanion, the RE atoms reside in cavities within the framework. While the Sc, Y, La, and Lu compounds exhibit Pauli-paramagnetic behavior, consistent with all atoms being closed shell, the other RETMAl2 compounds show paramagnetism along with magnetic ordering at low temperatures, in line with an open-shell trivalent oxidation state for the RE atoms. Solid-state 27Al NMR investigations were carried out on the Pauli-paramagnetic samples, all showing only a single central transition, in line with one crystallographic site for the respective atoms. The observed quadrupolar coupling constants and electric-field-gradient asymmetry parameters were found to be in good agreement with the density-functional-theory-calculated values. Isotropic resonance shifts are dominated by the Fermi-contact interactions with s-conduction electron densities at the Fermi edge (Knight shifts). The bonding characteristics mirror the electronic density of states and crystal chemistry of the family of intermetallic compounds under consideration. Both the Knight shifts and quadrupolar coupling constants can be predicted based on element-specific increments.
影响因子：
2
作者：
Massiot, D;Fayon, F;Hoatson, G
通讯作者：
Hoatson, G