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

Abstract

Future technologies are in need of solid-state materials showing the desired chemical and physical properties, and designing such materials requires a proper understanding of their electronic structures.

Examination of a Structural Preference in Quaternary Alkali-Metal (A) Rare-Earth (R) Copper Tellurides by Combining Experimental and Quantum-chemical Means

“…For that reason, it is reasonable to depict the Er–Te as well as Cu–Te bonds as polar covalent. It is remarkable that the Er–Te bonds exhibit a polar-covalent character, which is in full agreement with our bonding analyses ,,− , on different rare-earth-containing tellurides, but in contrast to previous ,,, classifications of rare-earth–tellurium bonds. In this context, it should be mentioned that the overall tendencies identified by the bonding analysis for the potassium-containing tellurides also agree with the trends revealed by a more recent bonding analysis on the quaternary Rb 3 Er 4 Cu 5 Te 10 ; yet, understanding the origins of the structural preferences at the atomic scale also requires to point out the differences between the bonding situations of the type-I- and -III-fashioned tellurides.…”

“…In this connection, it should be recapitulated that a strong bonding character is typically observed for interactions with valence electrons being localized between open-shell species, while the entire valence-electron delocalization as encountered for metal−metal bonds results in a weak bonding nature. 27,112 Likewise, ionic bonds typically correspond to smaller −ICOHP/bond values, and hence, a less bonding character than interactions with the valence electrons being located between open-shell species. 27,112 Therefore, the large Er−Te and Cu−Te −ICOHP/bond values clearly indicate a bonding character arising from valence electrons that are localized between open-shell species.…”

“…27,112 Likewise, ionic bonds typically correspond to smaller −ICOHP/bond values, and hence, a less bonding character than interactions with the valence electrons being located between open-shell species. 27,112 Therefore, the large Er−Te and Cu−Te −ICOHP/bond values clearly indicate a bonding character arising from valence electrons that are localized between open-shell species. For that reason, it is reasonable to depict the Er−Te as well as Cu−Te bonds as polar covalent.…”

“…While the relationships between the crystal structures and the electronic structures of the tellurides of the active metals are well , depicted by applying the Zintl–Klemm formalism, things look different for tellurides containing transition- or post-transition-metals. In the case of the latter, several of them belong to the recently introduced , incipient metal family, whose members exhibit a unique − electronic state.…”

Exploring the Impact of Lone Pairs on the Structural Features of Alkaline‐Earth (A) Transition‐Metal (M,M’) Chalcogenides (Q) AMM'Q3

“…As projected by the analyses of the DOS curves and the Mulliken charges, the nature of the Ba−Te interactions should be ionic, while the Ln−Te and Cu−Te interactions are supposed to show a polar‐covalent character. Such a tendency should [3c] translate into a weaker Ba−Te bonding character relative to the Cu−Te and Ln−Te bonds. Indeed, the Ba−Te −IpCOHP/bond values (BaLaCuTe 3 : 0.386 eV; BaGdCuTe 3 : 0.385 eV) are on average smaller than those of the Cu−Te (BaLaCuTe 3 : 0.818 eV; BaGdCuTe 3 : 0.897 eV) and Ln−Te interactions (BaLaCuTe 3 : 1.740 eV; BaGdCuTe 3 : 1.877 eV).…”