Revealing the Nature of Chemical Bonding in an ALn₂Ag₃Te₅-Type Alkaline-Metal (A) Lanthanide (Ln) Silver Telluride

• Main Authors: Kai C. Göbgen, Kai S. Fries, Fabian C. Gladisch, Richard Dronskowski, Simon Steinberg
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Inorganics
• Subjects: tellurides; Zintl phases; polar intermetallics
• Online Access: https://www.mdpi.com/2304-6740/7/6/70

Although the electronic structures of several tellurides have been recognized by applying the <i>Zintl</i>-<i>Klemm</i> concept, there are also tellurides whose electronic structures cannot be understood by applications of the aforementioned idea. To probe the appropriateness of the valence-electron transfers as implied by <i>Zintl</i>-<i>Klemm</i> treatments of ALn₂Ag₃Te₅-type tellurides (A = alkaline-metal; Ln = lanthanide), the electronic structure and, furthermore, the bonding situation was prototypically explored for RbPr₂Ag₃Te₅. The crystal structure of that type of telluride is discussed for the examples of RbLn₂Ag₃Te₅ (Ln = Pr, Nd), and it is composed of tunnels which are assembled by the tellurium atoms and enclose the rubidium, lanthanide, and silver atoms, respectively. Even though a <i>Zintl</i>-<i>Klemm</i> treatment of RbPr₂Ag₃Te₅ results in an (electron-precise) valence-electron distribution of (Rb⁺)(Pr³⁺)₂(Ag⁺)₃(Te^2&#8722;)₅, the bonding analysis based on quantum-chemical means indicates that a full electron transfer as suggested by the <i>Zintl</i>-<i>Klemm</i> approach should be considered with concern.