Nonclassical bonding in the novel structure of Ba2Bi3 and unexpected site preference in the coloring variant Ba2BiSb2

Siméon Ponou; Thomas F Fässler

doi:10.1021/ic0495719

Nonclassical bonding in the novel structure of Ba2Bi3 and unexpected site preference in the coloring variant Ba2BiSb2

Inorg Chem. 2004 Oct 4;43(20):6124-6. doi: 10.1021/ic0495719.

Authors

Siméon Ponou¹, Thomas F Fässler

Affiliation

¹ Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.

PMID: 15446850
DOI: 10.1021/ic0495719

Abstract

The new phase Ba(2)Bi(3) crystallizes in the W(2)CoB(2) structure type. Its structure contains rigorously planar anionic layers of (4.6.4.6)(4.6(2))(2) nets with three- and four-bonded Bi, that are separated by Ba atoms. An unexpected site preference is observed in the coloring variant Ba(2)BiSb(2) with Sb occupying only the three-bonded sites. The nonclassical bonding in the anionic network can be rationalized from a reformulation of the Zintl concept as (Ba(2+))(2)[Bi(3)](3)(-)(e(-)). Bonding distances suggest that the extra electron fills Bi-Bi antibonding states. The densities of states obtained from TB-LMTO-ASA calculations show metallic character for both compounds.