Ba2SnTe5, a novel alkaline-earth-metal tin telluride has been synthesized from a potassium polytelluride salt. Single-crystal X-ray diffraction analysis shows that this compound is a Zintl phase containing unique one-dimensional “Zweireinfach”-chains of corner-sharing SnTe4 tetrahedra and isolated (Te2)2- dimers. It represents the first ternary alkaline-earth-metal telluride synthesized from a polytelluride flux. Band calculations indicate strong covalent bonding between the Sn and Te within the chain. The interactions between the dimers and the chains are weak and repulsive.

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Bronze-colored crystals of Ba2SnTe5 are prepared by molten salt reactions using a Na2Te/BaTe/Te or a K2Te/BaTe/Te flux. Structure determination by XRD methods shows that Ba2SnTe5 (orthorhombic, space group Pnma, Z = 4) consists of layers of one-dimensional chains of ( SnTe3)2-and of isolated dimeric (Te2)2-Zintl anions. Ba2+ ions are located between the layers. The chains consist of corner-sharing distorted SnTe4 tetrahedra. Electronic band calculations by the extended Hueckel method indicate strong covalent bonding interactions between Sn and Te within the chains and weak and repulsive interactions between the chains and the dimer. The band structure suggests insulating or semiconducting behavior. -(LI, J.; LISZEWSKI, Y. Y.; MACADAMS, L. A.; CHEN, F.; MULLEY, S.; PROSERPIO, D. M.; Chem. Mater. 8 (1996) 3, 598-600; Dep. Chem., Rutgers Univ., Camden, NJ 08102, USA; EN)