Two closely related structure types with unprecedented bioctahedral rare-earth-metal clusters centered by transition metals: A{sub 2}R{sub 10}I{sub 17}Z{sub 2} (A = Rb, Cs; R = La, Ce, Pr; Z = Co, Ni, Ru, Os) and La{sub 10}I{sub 15}Os{sub 2}
- Iowa State Univ., Ames, IA (United States)
A family of compounds has been discovered in which pairs of octahedral rare-earth-metal clusters, each centered by a late transition metal Z, share a common edge. This R{sub 10}Z{sub 2} units, sheathed and interbridged by iodine atoms, occur in the quaternary phases Rb{sub 2}La{sub 10}I{sub 17}Co{sub 2}, Cs{sub 2}La{sub 10}I{sub 17}Z{sub 2} (Z = Co, Ni, Ru, Os), Cs{sub 2}Ce{sub 10}I{sub 17}Os{sub 2}, and Cs{sub 2}Pr{sub 10}I{sub 17}Z{sub 2}(Z = Co, Ru, Os) and in the ternary La{sub 10} I{sub 15}Os{sub 2}. All are obtained as black, air-sensitive crystals from reactions of RI{sub 3}, R, Z, and RbI or CsI as appropriate in welded Nb containers at 800-850{degree}C. The structure of Cs{sub 2} Ce{sub 10}I{sub 17}Os{sub 2} has been refined by single-crystal X-ray diffraction methods for comparison with the isotypic Cs{sub 2}La{sub 10}I{sub 17}Co{sub 2}, and the structure of a unique ternary La{sub 10}I{sub 15}Os{sub 2} has been defined. These new bioctahedral clusters may be regarded as the missing links between discrete clusters and infinite chains of condensed octahedral clusters among rare-earth-metal cluster halides that are stabilized by interstitial transition metals. The biclusters in both structures are extensively interconnected into three-dimensional arrays through bridging iodine atoms. The structural interconversion between Cs{sub 2}La{sub 10}I{sub 17}Os{sub 2} and La{sub 10}I{sub 15}Os{sub 2} + 2CsI may be easily visualized in terms of changes in iodide bridging modes and accommodation of cesium cations. 29 refs., 7 figs., 7 tabs.
- OSTI ID:
- 458607
- Journal Information:
- Journal of the American Chemical Society, Vol. 119, Issue 3; Other Information: PBD: 22 Jan 1997
- Country of Publication:
- United States
- Language:
- English
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