Revealing the Bonding Nature in an ALnZnTe3-Type Alkaline-Metal (A) Lanthanide (Ln) Zinc Telluride by Means of Experimental and Quantum-Chemical Techniques

Abstract

Tellurides have attracted an enormous interest in the quest for materials addressing future challenges, because many of them are at the cutting edge of basic research and technologies due to their remarkable chemical and physical properties. The key to the tailored design of tellurides and their properties is a thorough understanding of their electronic structures including the bonding nature. While a unique type of bonding has been recently identified for post-transition-metal tellurides, the electronic structures of tellurides containing early and late-transition-metals have been typically understood by applying the Zintl−Klemm concept; yet, does the aforementioned formalism actually help us in understanding the electronic structures and bonding nature in such tellurides? To answer this question, we prototypically examined the electronic structure for an alkaline metal lanthanide zinc telluride, i.e., RbDyZnTe3, by means of first-principles-based techniques. In this context, the crystal structures of RbLnZnTe3 (Ln = Gd, Tb, Dy), which were obtained from high-temperature solid-state syntheses, were also determined for the first time by employing X-ray diffraction techniques.

Bonding diversity in rock salt-type tellurides: examining the interdependence between chemical bonding and materials properties

“…The corresponding Mulliken and Löwdin charges of YTe, on the other side, clearly point to a small valence-electron transfer unlike that observed for the ionic SrTe, so the Y-Te contacts cannot be depicted as ionic. This outcome is in stark contrast to literature data [59][60][61][62] suggesting ionic rareearth-tellurium interactions, but agrees well with more recent research 23,25,26,28 revealing polar-covalent bonding nature and suggesting the Zintl-Klemm formalism as potentially misleading. Examining the projected COHP of YTe brings to light that the largest bonding contribution originates from Y-4d-Te-5p which changes from bonding to antibonding below the Fermi level.…”

“…In the cases of the tellurides containing transition-metals, the bonding nature is better described as polar-covalent such that applying the Zintl-Klemm idea to such tellurides could be misleading. [23][24][25][26][27][28] Within the most recent efforts on tellurides comprising posttransition-metals, a new bonding type dubbed 'metavalent' 21,29 or 'hyperbonding' 30 has been proposed. This type of bonding is expected to be at the frontier between entire valence-electron localization as well as delocalization and was introduced based on a portfolio of various quantities, seen both in experiment and calculation.…”

Eu2CuSe3 Revisited by Means of Experimental and Quantum‐Chemical Techniques

“…For instance, previous explorations [17] typically described lanthanideÀ tellurium bonds as ionic in the spirit of the Zintl-Klemm formalism; however, recent research [18] on tellurides containing lanthanides demonstrated that the bonding nature between lanthanide and tellurium atoms should be depicted as polar-covalent like contacts between transition-metals and post-transition-metal-elements. As the bonding nature of several tellurides containing transition-metals shows such attributes identified for polar intermetallics, [19] it was inferred [20] that these tellurides should be assigned to the family of the polar intermetallics rather than that of the typical Zintl-phase.…”

Homologous Alkali Metal Copper Rare-Earth Chalcogenides A2Cu2nLn4Q7+n (n = 1, 2, 3)

“…Quaternary alkali metal rare-earth chalcogenide materials A a M b Ln c Q d (A = alkali metal, M = metal, Ln = lanthanide, Q = chalcogen) have large chemical phase spaces encompassing a variety of structures and compositions, which have not yet been fully explored. Many of the known structure types form either three-dimensional (3D) frameworks, such as Rb 3 Cu 5 Nd 4 Te 10 , CsTb 3 STe 4 , or K 2 Ag 3 CeTe 4 with tunnels of alkali metals, or two-dimensional (2D) structures, such as CsGdZnSe 3 , RbTbZnTe 3 , RbLaGeS 4 , or KCu 2 EuTe 4 with alkali metal between the layers. The 3D structure types exhibit variations in the type of connections created between polyhedra to form the frameworks, in the shapes of the tunnels, and in the amounts of alkali metal atoms in the tunnels.…”