Cluster Chemistry in Electron-Poor Ae鈥揚t鈥揅d Systems (Ae = Ca, Sr, Ba): (Sr,Ba)Pt2Cd4, Ca6Pt8Cd16, and Its Known Antitype Er6Pd16<

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• 作者：Saroj L. Samal ; Fakhili Gulo ; John D. Corbett
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：March 4, 2013
• 年：2013
• 卷：52
• 期：5
• 页码：2697-2704
• 全文大小：513K
• 年卷期：v.52,no.5(March 4, 2013)
• ISSN：1520-510X

文摘

Three new ternary polar intermetallic compounds, cubic Ca₆Pt₈Cd₁₆, and tetragonal (Sr, Ba)Pt₂Cd₄ have been discovered during explorations of the Ae鈥揚t鈥揅d systems. Cubic Ca₆Pt₈Cd₁₆ (Fm-3m, Z = 4, a = 13.513(1) 脜) contains a 3D array of separate Cd₈ tetrahedral stars (TS) that are both face capped along the axes and diagonally bridged by Pt atoms to generate the 3D anionic network Cd₈[Pt(1)]_6/2[Pt(2)]_4/8. The complementary cationic surface of the cell consists of a face-centered cube of Pt(3)@Ca₆ octahedra. This structure is an ordered ternary variant of Sc₁₁Ir₄ (Sc₆Ir₈Sc₁₆), a stuffed version of the close relative Na₆Au₇Cd₁₆, and a network inverse of the recent Er₆Sb₈Pd₁₆ (compare Ca₆Pt₈Cd₁₆). The three groups of elements each occur in only one structural version. The new AePt₂Cd₄, Ae = Sr, Ba, are tetragonal (P4₂/mnm,Z = 2, a 鈮?8.30 脜, c 鈮?4.47 脜) and contain chains of edge-sharing Cd₄ tetrahedra along c that are bridged by four-bonded Ba/Sr. LMTO-ASA and ICOHP calculation results and comparisons show that the major bonding (Hamilton) populations in Ca₆Pt₈Cd₁₆ and Er₆Sb₈Pd₁₆ come from polar Pt鈥揅d and Pd鈥揝b interactions, that Pt exhibits larger relativistic contributions than Pd, that characteristic size and orbital differences are most evident for Sb 5s, Pt₈, and Pd₁₆, and that some terms remain incomparable, Ca鈥揅d versus Er鈥揚d.