Ce11Ge3.73(2)In6.27: Solid-state synthesis, crystal structure and site-preference

Jeon, Beom-Yong; Nam, Gnu; Lee, Dong Woo; Ok, Kang Min; You, Tae‐Soo

doi:10.1016/j.jssc.2015.07.049

Cited by 12 publications

(14 citation statements)

References 33 publications

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“…An optical microscopic image and an SEM image of the bundles of these cubic-shaped single crystals in the Ca 10.57(2) La 0.43 Sb 9.59(1) ingot are shown in Figure . All of our previously reported Ho 11 Ge 10 -type compounds, which include the RE 11 Ge 4 In 6– x M x (RE = La, Ce; M = Li, Ge; x = 1, 1.96), Ca 11– x Yb x Sb 10– y Ge z (0 ≤ x ≤ 9; 0 ≤ y ≤ 3; 0 ≤ z ≤ 3) systems, Ce 11 Ge 3.73(2) In 6.27 , Eu 11 Bi 8.07(2) Sn 1.93 , and Eu 10.74(2) K 0.26 Bi 9.14(2) Sn 0.86 , were also successfully synthesized by the same arc-melting method. However, the post-heat-treatment process at a certain temperature was apparently necessary after the initial arc-melting to grow large-enough single crystals for SXRD analysis.…”

Section: Resultsmentioning

confidence: 99%

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Lee

Ahn

Kim

et al. 2019

Crystal Growth & Design

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Four novel ternary Zintl phase compounds belonging to the Ca11–x RE x Sb10–y (RE = La, Ce, Nd, Sm; 0.18(4) ≤ x ≤ 0.43(2), 0.14(1) ≤ y ≤ 0.41(1)) system have been synthesized by arc-melting, and the Ho11Ge10-type crystal structure has been characterized for the isotypic title compounds by both powder and single crystal X-ray diffraction analyses. The intrinsically complex crystal structure is viewed as an assembly of the three distinctively shaped cationic polyhedra built from either seven or nine cations and the anionic frameworks constructed by the “dumbbell-shaped” Sb2 and the “square-shaped” Sb4 moieties. All of the four trivalent rare-earth metals were successfully introduced as n-type dopants to partially substitute divalent Ca atoms in the parental compound Ca11Sb10, which resulted in generating two or three Ca2+/RE3+ mixed-cationic sites. In particular, during these substitutions, we observed a unique site preference of Ca2+ and RE3+ among four available cationic sites, where the rare-earth metals with the higher electronegativities than Ca occupied particular atomic sites having the higher Q values. This type of site preference was conclusively explained by theoretical investigations using the tight-binding linear muffin-tin orbital method. Despite the successful n-type doping, the increased electrical conductivities σ and the decreased Seebeck coefficients S of Ca10.75(3)Nd0.25Sb9.82(1) and Ca10.82(4)Sm0.18Sb9.86(1) compared to those of Ca11Sb10 still presented the p-type rather than n-type characters. These unexpected behaviors should be attributed to ca. 7–20% of Sb3 deficiencies found at the “square-site” (Wyckoff 8h), which spontaneously occurred to reduce an energetically unfavorable antibonding character of the interatomic interaction between two Sb3 atoms at the square-site. Total and partial density of states of a hypothetical structural model Ca10.5Nd0.5Sb10, an SEM image of single crystals of Ca10.57(2)La0.43Sb9.59(1), and a TGA result of Ca10.82(4)Sm0.18Sb9.86(1) are also provided.

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Section: Resultsmentioning

confidence: 99%

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Lee

Ahn

Kim

et al. 2019

Crystal Growth & Design

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“…A series of comprehensive theoretical calculations were conducted by using TB-LMTO method with atomic sphere approximation (ASA) − to understand the cationic site-preference, ,, QVAL analyses, and overall electronic structure of the title compounds. In particular, to study the cationic site-preference, we designed three hypothetical Ca 5 Ge 2 Sb 6 -type models with an idealized composition of CaYb 4 Al 2 Sb 5.5 Ge 0.5 and assigned Ca at a different cationic site in each model.…”

Section: Experimental Sectionmentioning

confidence: 99%

Anionic Doping and Cationic Site Preference in CaYb₄Al₂Sb_6–xGe_x (x = 0.2, 0.5, 0.7): Origin of the Enhanced Seebeck Coefficient and the Structural Transformation

et al. 2019

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Three Zintl phase compounds belonging to the CaYb4Al2Sb6–x Ge x (x = 0.2, 0.5, 0.7; nominal compositions) system with various Ge-doping contents were successfully synthesized by arc-melting and were initially crystallized in the Ba5Al2Bi6-type phase (space group Pbam, Pearson codes oP26). However, after post-heat treatment at an elevated temperature, the originally obtained crystal structure was transformed into the homeotypic Ca5Ga2Sb6-type structure according to powder and single-crystal X-ray diffraction analyses. Two types of crystal structures share some isotypic structural moieties, such as the one-dimensional anionic chains formed by ∞ 1[Al2Sb8] and the void-filling Ca2+/Yb2+ mixed cations, but the slightly different spatial arrangements in each unit cell make these two structural types distinguishable. This series of title compounds is originally investigated to examine whether anionic p-type doping using Ge can successfully enhance thermoelectric (TE) properties of the Yb-rich CaYb4Al2Sb6–x Ge x series even after the phase transition from the Ba5Al2Bi6-type to the Ca5Ga2Sb6-type phase. More interestingly, we also reveal that the given structural transformation is triggered by the particularly different site-preference of Ca2+ and Yb2+ among three available cationic sites in each structure type, which is significantly affected by thermodynamic conditions of this system. Band structure and density of states analyses calculated by density functional theory using the tight-binding linear muffin-tin orbital method also prove that the Ge-doping actually increases band degeneracies and the number of resonant peaks near the Fermi level resulting in the improvement of Seebeck coefficients. Electron localization function analyses for the (0 1 0) sliced-plane and the 3D isosurface nicely illustrates the distortion of the paired-electron densities due to the introduction of Ge. The systematic TE property measurements imply that the attempted anionic p-type doping is indeed effective to improve the TE characteristics of the title CaYb4Al2Sb6–y Ge y system.

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“…9) were shown belong to this structure type. After it was realized (e.g., Rauscher et al 2007;Jeon et al 2016) that compounds isostructural with Ho 11 Ge 10 are potential thermoelectric material, syntheses of phases isostructural with Ho 11 Ge 10 soared, with over 30 compounds reported since 2012, although most of the new phases are versions of known phases doped to improve their thermoelectric capability.…”

Section: Kangjinlaite -A New Compound Of the Ho 11 Ge 10 Typementioning

confidence: 99%

Wenjiite, Ti10(Si,P,☐)7, and kangjinlaite, Ti11(Si,P)10, new minerals in the ternary Ti-P-Si system from the Luobusa ophiolite, Tibet, China

Xiong

Mugnaioli

et al. 2023

American Mineralogist

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temperature of the 4 minerals in the spheroid wenjiite → kangjinlaite → zhiqinite + badengzhuite is consistent with relationships reported in 9 binary systems containing intermetallic compounds of Ge and Sn isostructural with Mn 5 Si 3 and Ho 11 Ge 10 , in 8 of which the Mn 5 Si 3 analogue melts congruently, whereas the Ho 11 Ge 10 analogue never does. Instead the Ho 11 Ge 10 analogue melts peritectically, generally to an Mn 5 Si 3 analogue and less commonly to compounds with 5:4 stoichiometry. Final crystallization of the spheroid to zhiqinite + badengzhuite is expected to be well below the temperature of 1500 °C for the congruent melting of zhiqinite in the Ti-Si system, i.e. in the range of ~1100 -1300 °C.

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Ce11Ge3.73(2)In6.27: Solid-state synthesis, crystal structure and site-preference

Cited by 12 publications

References 33 publications

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Anionic Doping and Cationic Site Preference in CaYb₄Al₂Sb_6–xGe_x (x = 0.2, 0.5, 0.7): Origin of the Enhanced Seebeck Coefficient and the Structural Transformation

Wenjiite, Ti10(Si,P,☐)7, and kangjinlaite, Ti11(Si,P)10, new minerals in the ternary Ti-P-Si system from the Luobusa ophiolite, Tibet, China

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Ce11Ge3.73(2)In6.27: Solid-state synthesis, crystal structure and site-preference

Cited by 12 publications

References 33 publications

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca11–xRExSb10–y System

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca11–xRExSb10–y System

Anionic Doping and Cationic Site Preference in CaYb4Al2Sb6–xGex (x = 0.2, 0.5, 0.7): Origin of the Enhanced Seebeck Coefficient and the Structural Transformation

Wenjiite, Ti10(Si,P,☐)7, and kangjinlaite, Ti11(Si,P)10, new minerals in the ternary Ti-P-Si system from the Luobusa ophiolite, Tibet, China

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Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Effect of Rare-Earth Metals Substitution for Ca on the Crystal Structure and Thermoelectric Properties of the Ca_11–xRE_xSb_10–y System

Anionic Doping and Cationic Site Preference in CaYb₄Al₂Sb_6–xGe_x (x = 0.2, 0.5, 0.7): Origin of the Enhanced Seebeck Coefficient and the Structural Transformation