Importance of Cations in the Properties of Zintl Phases: The Electronic Structure of and Bonding in Metallic Na6TlSb41
The novel metallic compound Na(6)TlSb(4) consists of four-membered TlSb(3) rings joined by pairs of Sb atoms into Tl(2)Sb(8) units, the last of which is further interconnected into 1D anionic chains via Tl-Tl bonds. The contrast of its metallic conductivity with that of the 2 - e(-) poorer, electron...
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Published in | Inorganic chemistry Vol. 44; no. 16; pp. 5636 - 5640 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
08.08.2005
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Online Access | Get full text |
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Summary: | The novel metallic compound Na(6)TlSb(4) consists of four-membered TlSb(3) rings joined by pairs of Sb atoms into Tl(2)Sb(8) units, the last of which is further interconnected into 1D anionic chains via Tl-Tl bonds. The contrast of its metallic conductivity with that of the 2 - e(-) poorer, electron precise, and semiconducting Zintl phase K(6)Tl(2)Sb(3), which has virtually the same anionic network, has been investigated by ab initio LMTO-DFT methods. Sodium ion participation is found to be appreciable in the (largely) Sb p valence band and especially significant in an additional low-lying conduction band generated by antimony ppi and sodium orbitals. The one pyramidal 3-bonded Sb atom appears to be largely responsible for the interchain conduction process. The substitution of one Tl by Sb, which occurs when the countercation is changed from potassium in K(6)Tl(2)Sb(3) to sodium, yielding only Na(6)TlSb(4), is driven by a distinctly tighter packing, a corresponding increase in the Madelung energy, and binding of the excess pair of electrons in the new conduction band. |
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Bibliography: | istex:E69ACF38D90276FDD85DDB06A884AC40D212B820 ark:/67375/TPS-ZFWLXNFQ-V ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0020-1669 1520-510X |
DOI: | 10.1021/ic050128n |