YPdSn and YPd₂Sn: Structure, ⁸⁹Y solid state NMR and ¹¹⁹Sn M枚ssbauer spectroscopy

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• 作者：Christoph Hö ; ting^a ; Hellmut Eckert^b ; Thorsten Langer^a ; Inga Schellenberg^a ; Rainer Pö ; ttgen^a ; ^{pottgen@uni-muenster.de}
• 关键词：Stannides ; Crystal chemistry ; 89Y solid state NMR ; 119Sn Mö ; ssbauer spectroscopy
• 刊名：Journal of Solid State Chemistry
• 出版年：2012
• 期刊代码：130_00224596
• 类别：ch
• 出版时间：June, 2012
• 卷：190
• 期：Complete
• 页码：216-220
• 文件大小：391 K

摘要

The stannides YPdSn and YPd₂Sn were synthesized by high-frequency melting of the elements in sealed tantalum tubes. Both structures were refined on the basis of single crystal X-ray diffractometer data: TiNiSi type, Pnma, a=715.4(1), b=458.8(1), c=789.1(1) pm, wR2=0.0461, 510 F² values, 20 variables for YPdSn and MnCu₂Al type, Fm3炉m, a=671.44(8), wR2=0.0740, 55 F² values, 5 parameters for YPd₂Sn. The yttrium atoms in the new stannide YPdSn are coordinated by two tilted Pd₃Sn₃ hexagons (ordered AlB₂ superstructure). In the Heusler phase YPd₂Sn each yttrium atom has octahedral tin coordination and additionally eight palladium neighbors. The cubic site symmetry of yttrium is reflected in the ¹¹⁹Sn M枚ssbauer spectrum which shows no quadrupole splitting. In contrast, YPdSn shows a single signal at 未=1.82(1) mm/s subjected to quadrupole splitting of 螖E_Q=0.93(1) mm/s. Both compounds have been characterized by high-resolution ⁸⁹Y solid state NMR spectroscopy, which indicates the presence of strong Knight shifts. The spectrum of YPd₂Sn is characterized by an unusually large linewidth, suggesting the presence of a Knight shift distribution reflecting local disordering effects. The range of ⁸⁹Y Knight shifts of several binary and ternary intermetallic yttrium compounds is briefly discussed.