Structural Variations and Bonding Analysis of the Rare-Earth Metal Tellurides RETe_1.875±δ (RE = Ce, Pr, Sm, Gd; 0.004 ≤ δ ≤ 0.025)

Abstract

Crystals of RETe 1.875±δ (RE = Ce, Pr, Sm, Gd; 0.004 ≤ δ ≤ 0.025) were grown using alkali halide flux and chemical transport reactions. The crystal structures are described in space group Amm2 (no. 38), with lattice parameters of a = 13.3729(5) Å,

Superstructures and Chemical Bonding in Rare Earth Metal Polytellurides RETe2‐δ (RE=La−Nd; Sm−Tm; 0≤δ≤0.2)

“…The diffraction images of SmTe 1.87(1) and GdTe 1.88(1) , however, show a considerable amount of reflections contradicting the Acentered lattice, indicating that the domain ordering in these compounds tends to loose coherency. [41] Bonding analysis by COHP for Gd 8 Se 15 evidenced considerable stabilizing contributions between the formally negatively charged X 2 2À anions in the eight-membered ring around the vacancies whereas the other parts of the chalcogenide layer can reasonably well understood by assuming discrete X 2 2À and X 2À anions. [14,41] This points in the same direction as the ELI-D values found between the X 2 2À anions of the eight-ring in LaTe 1.9 .…”

“…[41] Bonding analysis by COHP for Gd 8 Se 15 evidenced considerable stabilizing contributions between the formally negatively charged X 2 2À anions in the eight-membered ring around the vacancies whereas the other parts of the chalcogenide layer can reasonably well understood by assuming discrete X 2 2À and X 2À anions. [14,41] This points in the same direction as the ELI-D values found between the X 2 2À anions of the eight-ring in LaTe 1.9 . [14] Table 4.…”

“…The correlated vacancy ordering of these compounds is still compatible with a commensurate supercell of the aristotype. The diffraction images of SmTe 1.87(1) and GdTe 1.88(1) , however, show a considerable amount of reflections contradicting the A ‐centered lattice, indicating that the domain ordering in these compounds tends to loose coherency [41] …”

“…In contrast, far fewer tellurides RE Te 2‐δ have been described in detail, partly because of synthetic issues, partly due to crystallographic complications. We could add some new examples to these rare earth metal tellurides and clarify their crystal structures recently [34,38–41] . We take this as an opportunity to briefly review some structural aspects as well as the chemical bonding and to discuss similarities and differences with respect to their lighter congeners.…”

“…We could add some new examples to these rare earth metal tellurides and clarify their crystal structures recently. [34,[38][39][40][41] We take this as an opportunity to briefly review some structural aspects as well as the chemical bonding and to discuss similarities and differences with respect to their lighter congeners. For more general reviews on polychalcogenides, the reader is referred to.…”