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Title: Two extended metal chain compounds, Y/sub 4/I/sub 5/C and Y/sub 6/I/sub 7/C/sub 2/. Synthesis, structure, properties, and bonding

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00283a024· OSTI ID:5828463

The title phases are obtained in high yield from the reactions of stoichiometric quantities of Y, YI/sub 3/, and graphite at 850-950/degree/C in welded Nb containers. The crystal structures of the two phases determined by standard x-ray diffraction means are related to those published for Er/sub 4/I/sub 5/ and Er/sub 6/I/sub 7/ (C2/m, Z = 2, /alpha/ = 18.479 (6) and 21.557 (8) /angstrom/, b = 3.947 (1) and 3.909 (1) /angstrom/, c = 8.472 (3) and 12.374 (6) /angstrom/, /beta/ = 103.22 (4) and 123.55 (3)/degree/, R/R/sub w/ = 4.6/5.4 and 3.2/3.7% for Y/sub 4/I/sub 5/C and Y/sub 6/I/sub 7/C/sub 2/, respectively). The two compounds contain infinite single and double chains of carbon-centered yttrium octahedra, respectively, condensed by edge-sharing and sheathed by edge-bridging iodine atoms together with square-planar iodine atoms that bridge between chains. Extended Hueckel MO band calculations were carried out for the empty and the carbon-centered compounds in both structures. Metal-based bands near E/sub F/ in the empty chains exhibit characteristic strong interactions with carbon valence orbitals that generate low-lying valence bands. E/sub F/ in both cases falls within a broad, metal-based conduction band. Resistivity and magnetic susceptibility measurements on Y/sub 6/I/sub 7/C/sub 2/ support the predicted metallic character. 26 refs., 11 figs., 3 tabs.

Research Organization:
Iowa State Univ., Ames (USA)
OSTI ID:
5828463
Journal Information:
Inorg. Chem.; (United States), Vol. 27:10
Country of Publication:
United States
Language:
English