Thermoelectric properties of the new tellurides SrSc2Te4 and BaSc2Te4 in comparison to BaY2Te4

Syntheses and characterization of two new layered ternary chalcogenides NaScQ2 (Q = Se and Te)

“…As expected, the Sc–Te distance of 2.946(1) Å in the NaScTe 2 structure is longer than that of NaScSe 2 due to the larger size of Te than Se. The observed Sc–Te distance compares well with those found in SrSc 2 Te 4 (2.8917(12)–2.9764(19) Å), 6 RbSc 5 Te 8 (2.843(2)–3.034(2) Å), 29 and TlScTe 2 (2.9341(6) Å). 53 The NaTe 6 also has almost regular octahedron geometry with six identical Na–Te interactions of 3.218(1) Å that is in concordance with the Na–Te distances of the related NaCuZrTe 3 (3.168(15)–3.244(15) Å) 54 and NaMn 1.56 Te 2 (3.255(2) Å) structures.…”

Modulated Linear Tellurium Chains in Ba3ScTe5: Synthesis, Crystal Structure, Optical and Resistivity Studies, and Electronic Structure

“…The Te–Sc–Te angles of these octahedra are also very close to those of the ideal octahedron with m –3 m symmetry (Table ). A comparison of the Sc–Te distances in Ba 3 ScTe 5 with the corresponding distances found in the related structures such as BaSc 2 Te 4 [2.878(2)–2.958(1) Å], SrSc 2 Te 4 [2.892(1)–2.977(1) Å], RbSc 5 Te 8 [2.890(1)–2.926(1) Å], and TlScTe 2 [2.9341(6) Å] reveals good agreement with the single Sc 3+ –Te bonding.…”

“…As a consequence of face-sharing, the Sc···Sc distances are expected to be shorter than those in related structures that have edge-sharing or corner-sharing units of Sc octahedra. Indeed, the Sc···Sc interactions of 3.4167(1) Å in Ba 3 ScTe 5 are shorter compared with those in TlScTe 2 [4.2128(4) Å], BaSc 2 Te 4 [4.2692(1) Å], and CsCu 2 Sc 3 Te 6 [4.0430(1) Å] that have edge-shared ScTe 6 octahedra. Only RbSc 5 Te 8 shows a Sc···Sc interaction of 3.6590(1) Å, which is closer to the corresponding interactions in Ba 3 ScTe 5 .…”

“…The ternary Ak−Sc−Te system (Ak = Mg, Ca, Sr, and Ba) contains only two compounds, BaSc2Te4 and SrSc2Te4, that adopt the well-known CaFe2O4 structure type. 14 In this report, we present the synthesis and crystal structure of the first polytelluride Ba3ScTe5 of the Ak−Sc−Te ternary system. Its structure is modulated.…”

“…In the past few decades, metal chalcogenides with narrow band gaps and low thermal conductivities have been of interest for their promising thermoelectric properties. Examples include AkM 2 Te 4 (Ak = Sr and Ba; M = Sc and Y), 14 BaCu 2−x Ag x Te 2 , 15 Ba 3 Cu 14−x Te 12 , 16 and YCuTe 2 . 1 The structural chemistry of metal chalcogenides is also very rich.…”