Ternary Rare-Earth Manganese Bismuthides: Structures and Physical Properties of RE3MnBi5 (RE = La-Nd) and Sm2Mn3Bi6

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• 作者：Oksana Ya. Zelinska ; Arthur Mar
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：January 7, 2008
• 年：2008
• 卷：47
• 期：1
• 页码：297 - 305
• 全文大小：668K
• 年卷期：v.47,no.1(January 7, 2008)
• ISSN：1520-510X

文摘

Investigations in the ternary RE-Mn-Bi systems where RE is an early rare earth element have revealed theexistence of the polybismuthides RE₃MnBi₅ (RE = La-Nd), previously known only for the Ce member, and thenew compound Sm₂Mn₃Bi₆. Their structures were determined from single-crystal X-ray diffraction data. TheRE₃MnBi₅ compounds adopt the hexagonal inverse Hf₅Cu₃Sn-type structure (Pearson symbol hP18, space groupP6₃/mcm, a = 9.7139(11)-9.5438(16) Å, c = 6.4883(7)-6.4089(11) Å for RE = La-Nd), containing chains offace-sharing Mn-centered octahedra. Sm₂Mn₃Bi₆ adopts a new monoclinic structure type (Pearson symbol mP22,space group P2₁/m, a = 10.3917(8) Å, b = 4.4557(3) Å, c = 13.2793(10) Å, = 108.0100(10)) in which theMn centers are coordinated by Bi atoms in diverse geometries (distorted octahedral, trigonal bipyramidal, anddistorted tetrahedral (seesaw)) and participate in extensive metal-metal bonding in the form of chains of Mn₃clusters. Homoatomic bonding interactions involving nominally anionic Bi atoms are manifested as one-dimensionalBi chains in RE₃MnBi₅ and as four-atom-wide Bi ribbons in Sm₂Mn₃Bi₆. Electrical resistivity measurements onsingle crystals revealed metallic behavior with prominent transitions near 40 K for RE₃MnBi₅ and 50 K forSm₂Mn₃Bi₆. Magnetic susceptibility measurements showed that Pr₃MnBi₅ undergoes magnetic ordering near 25 K.