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Author Lulei, M. ♦ Martin, J. D. ♦ Corbett, J. D.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ LANTHANUM IODIDES ♦ CRYSTAL STRUCTURE ♦ IRON IODIDES ♦ CERIUM IODIDES ♦ MANGANESE IODIDES ♦ CHEMICAL REACTION YIELD ♦ TRICLINIC LATTICES ♦ X-RAY DIFFRACTION
Abstract Reactions of KI, La, LaI{sub 3}, and Fe in niobium tubes at 900{degrees}C yield black crystals of La{sub 12}I{sub 17}Fe{sub 2} which were characterized by single-crystal X-ray diffraction (triclinic, P1, Z = 1, a = 11.967(8), b = 11.851(6), c = 9.918(7) {angstrom}, {alpha} = 114.59(5){degrees}, {beta} = 104.83(6){degrees}, {gamma} = 93.05(5){degrees}, R(F)/R{sub w} = 3.8/4.3%). Similar experiments also gave the isostructural Ce{sub 12}I{sub 17}mn{sub 2} according to the Guninier powder pattern (a = 11.863(6), b = 11.840(6), c = 9.857(5) {angstrom}, {alpha} = 14.90(4){degrees}, {beta} = 104.47(4){degrees}, {gamma} = 93.28(4){degrees}). The Pr{sub 12}I{sub 17}Fe{sub 2}-type structure contains octahedral rare-earth-metal cluster units R{sub 6} centered by a transition-metal atom Z and sheathed by iodine atoms. These are closely linked by seven I{sup i-i} and one I{sup i-a-a} bridges that lead to the unusually low I:Pr ratio for phases with isolated clusters. The compounds reported here together with Pr{sub 12}I{sub 17}Z{sub 2}, Z = Fe, Re are the only phases known to adopt this structure type. The La{sub 12}I{sub 17}Fe{sub 2} phase for data are consistent with equal numbers of 17-e and 18-e (closed shell) clusters, with {mu} = 1.11 BM for the former.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-09-01
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 125
Issue Number 2


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