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The first sodalite-type telluride, Cs3Cu20Te13, has been successfully synthesized by solid-state reactions. The single-crystal X-ray diffraction data reveal its cubic symmetry and lattice parameters of a = 14.7557(6) Å, V = 3212.8(2) ų, and Z = 4. The three-dimensional network is constructed by (CuTe)12 tetrakaidecahedra centered by different guest species (either a Cs+ or a Te2-@Cu8 cube) extending in a 2 × 2 × 2 supercell with respect to the conventional sodalite. Density functional theory analysis uncovers the unique feature of the p-type metallic sodalite framework accommodating anionic guest species, which agrees well with the experimental metallic electrical conductivity and Pauli paramagnetism. [ABSTRACT FROM AUTHOR]

A new valence precise Zintl phase, Pr4MnSb9, has been successfully synthesized by solid-state reaction at high temperature. The single-crystal X-ray diffraction data reveal its monoclinic symmetry in the space group C2/m (No. 12) with a = 24.12(2) Å, b = 4.203(3) Å, c = 15.67(2) Å, β = 98.05(1)°, and Z = 4. The structure is characterized by the covalent three-dimensional network constructed by two types of five-atom-wide Sb57- ribbons that are joined by 6-fold coordinated Mn3+ cations, through which the narrower three-atom-wide Sb35- ribbons are attached as a tag, and interstitial Pr3+ cations and single Sb3- anions locate within the tunnels. Its magnetic susceptibility and isothermal hysteresis suggest ferrimagnetic behavior. The electrical conductivity and Seebeck coefficient of the cold-pressed pellet suggest a semimetal feature that agrees with the spin-polarized calculation results using the right-binding linear muffin-tin orbital (TB-LMTO) method. [ABSTRACT FROM AUTHOR]

Dark-red CsMnInTe3 is synthesized by a solid-state approach using CsCl as the reactive flux. This layered compound is constructed by T3 supertetrahedra and crystallizes in the space group C2/c with a = 12.400(7) A, b = 12.400(7) A, c = 24.32(2) A, ß = 97.31(2)°, and V = 927.07(6) A³. The electrostatic interactions cause tilting of the supertetrahedra layers, and the value of the tilting angle is fixed by a structure index, ß' = 180° -- arccos(a/4c). Such an index is valid for all of die members in this family known to date. [ABSTRACT FROM AUTHOR]

The most advanced UV–vis and IR NLO materials are usually borates and chalcogenides, respectively. But thioborates, especially thio-borometalates, are extremely rare. Here, four new such compounds are discovered by solid state reactions representing 0D structures constructed by isolated BQ3 trigonal planes and discrete MQ3 pyramids with Ba2+ cations filling among them, centrosymmetric monoclinic P21/c Ba3(BS3)1.5(MS3)0.5 (M = Sb, Bi) 1, 2 with a = 12.9255(9), 12.946(2) Å; b = 21.139(2), 21.170(2)Å; c = 8.4194(6), 8.4207(8) Å; β = 101.739(5), 101.688(7)°; V = 2252.3(3), 2259.9(3) ų and noncentrosymmetric hexagonal P62m Ba3(BQ3)(SBQ3) (Q = S, Se) 3, 4 with a = b = 17.0560(9), 17.720(4) Å; c = 10.9040(9), 11.251(3) Å; V = 2747.1(3), 3060(2) ų. 3 exhibits the strongest SHG among thioborates that is about three times that of the benchmark AgGaS2 at 2.05 μm. 1 and 3 also show an interesting structure relationship correlated to the size mismatching of the anionic building units that can be controlled by the experimental loading ratio of B:Sb. Syntheses, structure characterizations, and electronic structures based on the density functional theory calculations are reported. [ABSTRACT FROM AUTHOR]

A quaternary narrow-band-gap semiconductor, Ba 2 Cr 4 GeSe 10 , has been discovered by solid-state reaction. It features a new structure type and crystallizes in the triclinic space group P1̅ (No. 2). The featured 2D anionic layers are constructed by condensed CrSe 6 octahedra that are stacking along the c axis, with dispersed GeSe 4 tetrahedra and located Ba 2+ cations forming these layers. The energy-band structure shows a clear separation between the region of electronic conduction and the zone of electronic insulation. Significantly, an undoped Ba 2 Cr 4 GeSe 10 sample shows a desirable low thermal conductivity κ T (0.51-0.87 W/m·K) and a high Seebeck coefficient S (351-404 μV/K) and reaches a ZT ≈ 0.08 at 773 K.

Thermoelectric (TE) materials are of worldwide interest for energy sustainability through direct waste-heat-to-electricity conversion. Practically, a TE power generator requires a large working temperature gradient; to achieve high efficiency, key TE materials with high ZT values are necessary and, furthermore, their ZT values should decline as little as possible over the imposed temperature range. Unfortunately, sharp ZT declines in all of the known materials are inevitable. Here we found the bulk superionic α-Ag(1-x)CuSe material exhibits unusual weakly temperature-dependent ZT values in the range of 480-693 K with the smallest ZT-T slope known to date. These result from the Seebeck coefficient balance of the countercontributions of holes and electrons and the weakly temperature-dependent thermal conductivity.