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Thermoelectric properties of BiSbTe-type alloys prepared by chill-casting and cryo-milling

The thermoelectric properties of Bi x Sb 1-x Te 3 processed through milling have been extensively studied with varied results that needs to be rationalized. Since cryo-milling is a relatively cleaner milling process compared to other milling processes, in this study we explore this technique to reduce the particle size prior to compaction to get an insight into the thermoelectric properties. We first report the results of cryomilled BiSbTe 3 compacted by spark plasmas sintering (SPS) process and show that milling leads to a change in transport behavior from ‘p’ to ‘n’ type similar to that reported for Bi 2 Te 3 . It is shown that the defects induced by milling is responsible for this change in materials behavior. We further study the effect of change in Bi to Sb ratio and excess tellurium on the thermoelectric properties when processed through cryo-milling as well as casting using a chilled copper block. Excess tellurium leads to a microstructure containing a fraction of layered eutectic that gets further fragmented during cryo-milling. Although the Seebeck coefficient does not change significantly, reflecting the cleanliness of the process, the thermal conductivity changes during hot compaction leading to an improvement of ZT. However, a comparison of all the reported results does not reveal any systematics in thermoelectric properties reflecting the difficulties with these materials.

36 MATERIALS SCIENCE↗

Materials Data on Sb4(TeSe)3 by Materials Project

Sb4(TeSe)3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded to one Te2- and five Se2- atoms to form SbTeSe5 octahedra that share corners with three equivalent SbTe3Se3 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. The Sb–Te bond length is 3.05 Å. There are a spread of Sb–Se bond distances ranging from 2.86–3.02 Å. In the second Sb3+ site, Sb3+ is bonded to two equivalent Te2- and four Se2- atoms to form SbTe2Se4 octahedra that share corners with three equivalent SbTe3Se3 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. Both Sb–Te bond lengths are 3.00 Å. There are a spread of Sb–Se bond distances ranging from 2.79–3.05 Å. In the third Sb3+ site, Sb3+ is bonded to three Te2- and three Se2- atoms to form SbTe3Se3 octahedra that share corners with three equivalent SbTe2Se4 octahedra and edges with nine SbTeSe5 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are one shorter (2.99 Å) and two longer (3.01 Å) Sb–Te bond lengths. There are two shorter (3.03 Å) and one longer (3.04 Å) Sb–Se bond lengths. In the fourth Sb3+ site, Sb3+ is bonded to three Te2- and three Se2- atoms to form a mixture of edge and corner-sharing SbTe3Se3 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (3.00 Å) and one longer (3.01 Å) Sb–Te bond lengths. There are one shorter (3.03 Å) and two longer (3.07 Å) Sb–Se bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three Sb3+ and one Te2- atom. The Te–Te bond length is 3.78 Å. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to three Sb3+ and one Se2- atom. The Te–Se bond length is 4.00 Å. In the third Te2- site, Te2- is bonded in a 5-coordinate geometry to three Sb3+, one Te2-, and two equivalent Se2- atoms. Both Te–Se bond lengths are 4.00 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Sb3+ atoms to form edge-sharing SeSb6 octahedra. In the second Se2- site, Se2- is bonded to six Sb3+ atoms to form edge-sharing SeSb6 octahedra. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Sb3+ and three Te2- atoms.

36 MATERIALS SCIENCE↗

Thermodynamic properties of the Nd-Bi system via emf measurements, $\mathrm{DFT}$ calculations, machine learning, and $\mathrm{CALPHAD}$ modeling

Thermodynamic properties of the Nd-Bi system were investigated using a combination of experimental measurements, first-principles calculations based on density functional theory (DFT), data mining and machine learning (DM + ML) predictions, and calculation of phase diagrams (CALPHAD) modeling. The electromotive force (emf) of Nd-Bi alloys in molten LiCl-KCl-NdCl 3 at 773–973 K was measured via coulometric titration of Nd into Bi for the determination of thermochemical properties such as activity coefficients and solubilities of Nd in Bi. A new peritectic reaction of [liquid + NdBi 2 = Nd 3 Bi 7 ] at 774 K was confirmed using differential scanning calorimetry, structural (X-ray diffraction), and microstructural (scanning electron microscopy) analyses. The unknown crystal structure of NdBi2 was suggested to be a mixture of the anti-La 2 Sb configuration and the La 2 Te-type configuration based on ML predictions for over 26,000 data-mined AB 2 -type configurations together with DFT-based verifications. Using the newly acquired experimental data and DFT-based calculations, the thermodynamic description of the Nd-Bi system was remodeled, and a more complete Nd-Bi phase diagram was calculated, including the Nd 3 Bi 7 compound, invariant transition reactions, and liquidus temperatures.

36 MATERIALS SCIENCE↗

Materials Data on CsSbTeO6 by Materials Project

CsSbTeO6 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Cs1+ is bonded to six O2- atoms to form CsO6 octahedra that share corners with six equivalent SbO6 octahedra and corners with six equivalent TeO6 octahedra. The corner-sharing octahedra tilt angles range from 67–68°. There are a spread of Cs–O bond distances ranging from 3.11–3.17 Å. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with two equivalent SbO6 octahedra, corners with four equivalent TeO6 octahedra, and corners with six equivalent CsO6 octahedra. The corner-sharing octahedra tilt angles range from 44–68°. There are two shorter (1.98 Å) and four longer (2.02 Å) Sb–O bond lengths. Te6+ is bonded to six O2- atoms to form TeO6 octahedra that share corners with two equivalent TeO6 octahedra, corners with four equivalent SbO6 octahedra, and corners with six equivalent CsO6 octahedra. The corner-sharing octahedra tilt angles range from 44–68°. There is four shorter (1.94 Å) and two longer (1.98 Å) Te–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two equivalent Te6+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Cs1+ and two equivalent Sb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one Sb5+, and one Te6+ atom.

36 MATERIALS SCIENCE↗

Materials Data on Ge3(SbTe3)2 by Materials Project

Ge3Sb2Te6 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Ge3Sb2Te6 sheets oriented in the (0, 0, 1) direction. there are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with nine GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–14°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form a mixture of distorted edge and corner-sharing GeTe6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are three shorter (2.84 Å) and three longer (3.40 Å) Ge–Te bond lengths. In the third Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.01 Å) and three longer (3.21 Å) Sb–Te bond lengths. In the second Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.18 Å) Sb–Te bond lengths. There are six inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Sb atoms to form a mixture of edge and corner-sharing TeSb6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form TeGe3Sb3 octahedra that share corners with three equivalent TeSb6 octahedra and edges with nine TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third Te2- site, Te2- is bonded to six Ge4+ atoms to form distorted TeGe6 octahedra that share corners with three equivalent TeGe3Sb3 octahedra and edges with nine TeGe6 octahedra. The corner-sharing octahedral tilt angles are 12°. In the fourth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms. In the fifth Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. In the sixth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗

On the chemical composition of L-chondrites

Radiochemical neutron activation analysis of Ag, As, Au, Bi, Co, Cs, Ga, In, Rb, Sb, Te, Tl, and Zn and major element data in 14 L4-6 and 3 LL5 chondrites indicates that the L group is unusually variable and may represent at least 2 subgroups differing in formation history. Chemical trends in the S/Fe rich subgroup support textural evidence indicating late loss of a shock formed Fe-Ni-S melt; the S/Fe poor subgroup seemingly reflects nebular fractionation only. Highly mobile In and Zn apparently reflect shock induced loss from L chondrites. However, contrasting chemical trends in several L chondrite sample sets indicate that these meteorites constitute a more irregular sampling of, or more heterogeneous parent material than do carbonaceous or enstatite chondrites. Data for 15 chondrites suggest higher formation temperatures and/or degrees of shock than for LL5 chondrites.

Neal, C. W.↗

A stoichiometrically conserved homologous series with infinite structural diversity

Here, we describe a compositionally guided structural evolution within a stoichiometrically conserved framework, BaSbQ 3 (Q = Te 1−x S x ), where each value of x gives rise to a distinct phase. The fundamental building blocks, A 1 (BaSbSTe 2 ) and B n (Ba n Sb n S n−1 Te 2n+1 ), were composed of modular double rocksalt slabs stacked with functional polytelluride zigzag chains, with each phase differing only in the size and assembly of these blocks. Ten compounds were synthesized that maintained a coherent chemical identity that arose from this isovalent, isoelectronic substitution of Te and S. We envision that the phase formation at a molecular level unfolds in stages of extension, termination, and assembly and propose a design concept of “anionic disparity,” where phase homologies and polytelluride hierarchical networks can be controlled by leveraging differences in anion electron affinity and sizes.

Zhao, Hengdi [Argonne National Laboratory (ANL), A↗

Decoding the Atomic Structure of Ga 2 Te 5 Pulsed Laser Deposition Films for Memory Applications Using Diffraction and First-Principles Simulations

Neuromorphic computing, reconfigurable optical metamaterials that are operational over a wide spectral range, holographic and nonvolatile displays of extremely high resolution, integrated smart photonics, and many other applications need next-generation phase-change materials (PCMs) with better energy efficiency and wider temperature and spectral ranges to increase reliability compared to current flagship PCMs, such as Ge 2 Sb 2 Te 5 or doped Sb 2 Te. Gallium tellurides are favorable compounds to achieve the necessary requirements because of their higher melting and crystallization temperatures, combined with low switching power and fast switching rate. Ga 2 Te 3 and non-stoichiometric alloys appear to be atypical PCMs; they are characterized by regular tetrahedral structures and the absence of metavalent bonding. The sp 3 gallium hybridization in cubic and amorphous Ga 2 Te 3 is also different from conventional p-bonding in flagship PCMs, raising questions about its phase-change mechanism. Furthermore, gallium tellurides exhibit a number of unexpected and highly unusual phenomena, such as nanotectonic compression and viscosity anomalies just above their melting points. Using high-energy X-ray diffraction, supported by first-principles simulations, we will elucidate the atomic structure of amorphous Ga 2 Te 5 PLD films, compare it with the crystal structure of tetragonal gallium pentatelluride, and investigate the electrical, optical, and thermal properties of these two materials to assess their potential for memory applications, among others.

36 MATERIALS SCIENCE↗

Chemical studies of L-chondrites. I - A study of possible chemical sub-groups

Radiochemical neutron activation analysis of Ag, As, Au, Bi, Co, Cs, Ga, In, Rb, Sb, Te, Tl and Zn and major element data in 14 L4-6 and 3 LL5 chondrites indicates that the L-group is unusually variable and may represent at least 2 sub-groups differing in formation history. Chemical trends in the S/Fe-rich sub-group support textural evidence indicating late loss of a shock-formed Fe-Ni-S melt; the S/Fe-poor sub-group seemingly reflects nebular fractionation only. Highly mobile In and Zn apparently reflect shock-induced loss from L-chondrites. Data for L5 chondrites suggest higher formation temperatures and/or degrees of shock than for LL5 chondrites.

Neal, C. W.↗

Evaluation of Sb-Nd and Te-Nd phases within the U-Zr fuel matrix and their interactions with HT9 alloy

Antimony (Sb) and tellurium (Te) were investigated as potential additives for U-10Zr (wt.%) metallic fuel to limit the fuel-cladding chemical interaction (FCCI) with HT-9 alloy. Neodymium (Nd) was utilized to simulate the formation of lanthanide-based solid fission products which are known to play a detrimental role in FCCI. Fuel alloys of U-Zr-Sb-Nd and U-Zr-Te-Nd were evaluated in their annealed condition and compared against their as-cast conditions. Isothermal diffusion couple experiments were performed between U-Zr-Nd, U-Zr-Sb-Nd, and U-Zr-Te-Nd against the cladding alloy HT9 to evaluate the effectiveness of the additives to stabilize Nd within the fuel alloys, as well as investigate the interaction regions that form between the different fuel alloys and HT9. Further, SbNd and Sb 3 Nd 4 , and TeNd are found to be the primary neodymium-based phases formed in the U-Zr-Sb-Nd and U-Zr-Te-Nd alloys, respectively. The zirconium-based phase, Zr 2 Sb, is also found to form within the former alloy. All phases were found to remain stable through the diffusion experiments and exhibited no interaction with HT9 constituent elements. Preferential interaction between Nd with additivities Te and Sb compared to constituting elements in HT9 was further verified based on density functional theory (DFT) calculated enthalpy of mixing.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Materials Data on Li4CrSb(TeO6)2 by Materials Project

Li4CrSb(TeO6)2 is Ilmenite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.93–2.50 Å. In the second Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.95–2.42 Å. In the third Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 1.99–2.30 Å. In the fourth Li1+ site, Li1+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 1.92–2.61 Å. Cr5+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six TeO6 octahedra. The corner-sharing octahedra tilt angles range from 36–39°. There are a spread of Cr–O bond distances ranging from 1.99–2.07 Å. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with six TeO6 octahedra. The corner-sharing octahedra tilt angles range from 40–43°. There are a spread of Sb–O bond distances ranging from 1.97–2.04 Å. There are two inequivalent Te5+ sites. In the first Te5+ site, Te5+ is bonded to six O2- atoms to form TeO6 octahedra that share corners with two equivalent CrO6 octahedra and corners with four equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of Te–O bond distances ranging from 1.90–2.01 Å. In the second Te5+ site, Te5+ is bonded to six O2- atoms to form TeO6 octahedra that share corners with two equivalent SbO6 octahedra and corners with four equivalent CrO6 octahedra. The corner-sharing octahedra tilt angles range from 36–42°. There are a spread of Te–O bond distances ranging from 1.91–2.01 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded to two Li1+, one Sb5+, and one Te5+ atom to form a mixture of distorted edge and corner-sharing OLi2SbTe tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Cr5+, and one Te5+ atom. In the third O2- site, O2- is bonded to two Li1+, one Cr5+, and one Te5+ atom to form distorted corner-sharing OLi2CrTe tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Sb5+, and one Te5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Cr5+, and one Te5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Sb5+, and one Te5+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Sb5+, and one Te5+ atom. In the eighth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Li1+, one Cr5+, and one Te5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Sb5+, and one Te5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Li1+, one Cr5+, and one Te5+ atom. In the eleventh O2- site, O2- is bonded to two Li1+, one Cr5+, and one Te5+ atom to form a mixture of distorted edge and corner-sharing OLi2CrTe tetrahedra. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Sb5+, and one Te5+ atom.

36 MATERIALS SCIENCE↗

Electronic Topological Transition as a Route to Improve Thermoelectric Performance in Bi 0.5 Sb 1.5 Te 3

The electronic structure near the Fermi surface determines the electrical properties of the materials, which can be effectively tuned by external pressure. Bi0.5Sb1.5Te3 is a p-type thermoelectric material which holds the record high figure of merit at room temperature. Here it is examined whether the figure of merit of this model system can be further enhanced through some external parameter. With the application of pressure, it is surprisingly found that the power factor of this material exhibits λ behavior with a high value of 4.8 mW m –1 K –2 at pressure of 1.8 GPa. Such an enhancement is found to be driven by pressure-induced electronic topological transition, which is revealed by multiple techniques. Together with a low thermal conductivity of about 0.89 W m –1 K –1 at the same pressure, a figure of merit of 1.6 is achieved at room temperature. The results and findings highlight the electronic topological transition as a new route for improving the thermoelectric properties.

36 MATERIALS SCIENCE↗

Materials Data on BiSbTe3 by Materials Project

BiSbTe3 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three BiSbTe3 sheets oriented in the (0, 0, 1) direction. Bi3+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent BiTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (3.08 Å) and three longer (3.28 Å) Bi–Te bond lengths. Sb3+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent BiTe6 octahedra, edges with three equivalent BiTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (3.03 Å) and three longer (3.21 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Bi3+ and three equivalent Sb3+ atoms to form edge-sharing TeBi3Sb3 octahedra. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Bi3+ atoms. In the third Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Sb3+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on DySbTe3 by Materials Project

DySbTe3 is Calaverite-derived structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three DySbTe3 sheets oriented in the (0, 0, 1) direction. Dy3+ is bonded to six Te2- atoms to form DyTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent DyTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (3.01 Å) and three longer (3.18 Å) Dy–Te bond lengths. Sb3+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent DyTe6 octahedra, edges with three equivalent DyTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (3.00 Å) and three longer (3.30 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Dy3+ and three equivalent Sb3+ atoms to form distorted edge-sharing TeDy3Sb3 octahedra. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb3+ atoms. In the third Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Dy3+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on Sn(SbTe2)2 by Materials Project

SnSb2Te4 is MAX Phase-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three SnSb2Te4 sheets oriented in the (0, 0, 1) direction. Sn2+ is bonded to six equivalent Te2- atoms to form SnTe6 octahedra that share corners with six equivalent SbTe6 octahedra, edges with six equivalent SnTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Sn–Te bond lengths are 3.17 Å. Sb3+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent SnTe6 octahedra, edges with three equivalent SnTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (3.03 Å) and three longer (3.22 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb3+ atoms. In the second Te2- site, Te2- is bonded to three equivalent Sn2+ and three equivalent Sb3+ atoms to form a mixture of edge and corner-sharing TeSn3Sb3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

Abundance of 17 trace elements in carbonaceous chondrites.

Seventeen trace elements (Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Rb, Re, Sb, Se, Te, Tl, U, and Zn) were measured by neutron activation analysis in eight C1 samples (1 Alais, 3 Ivuna, 4 Orgueil and in three C2 samples (one each of Mighei, Murchison, Murray). The results show far less scatter than earlier literature data. The standard deviation of a single measurement from the mean of eight C1 samples lies between 2 and 14%, except for the following four elements: Au, Ag, Rb, and Br. The first two probably reflect contamination and sample heterogeneity, the last two, analytical error. Apparently C1 chondrites have a far more uniform composition than some authors have claimed.

Kraehenbuehl, U.↗

Meteoritic and non-meteoritic trace elements in Luna 16 samples.

Two Luna 16 soils have been analyzed for Ag, Au, Bi, Br, Cd, Co, Cs, Cu, Ga, Ge, In, Ur, Ni, Rb, Re, Sb, Se, Te, Tl, and Zn. A meteoritic component similar to that in Apollo 11 and 12 soils seems to be present, corresponding to about 1.5 to 2% Cl chondrites or equivalent. It probably consists largely of micrometeorites. Three elements show strong enrichments compared to Apollo 11 and 12 soils: Cd (5 x to 200 x), Ag (5 x to 10 x), and Bi (3 x). Presumably these elements were brought in by Cd-Ag-Bi rich material, similar to that in Unit VI of Apollo core 12028.

Laul, J. C.↗

Materials Data on Ge13Sb13Te32 by Materials Project

Ge13Sb13Te32 is Orthorhombic Perovskite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirteen inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded in a 5-coordinate geometry to six Te2- atoms. There are a spread of Ge–Te bond distances ranging from 2.77–3.50 Å. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 14–17°. There are a spread of Ge–Te bond distances ranging from 2.77–3.32 Å. In the third Ge4+ site, Ge4+ is bonded to five Te2- atoms to form distorted GeTe5 square pyramids that share a cornercorner with one GeTe6 octahedra, corners with four SbTe6 octahedra, an edgeedge with one GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 14–81°. There are a spread of Ge–Te bond distances ranging from 2.75–3.25 Å. In the fourth Ge4+ site, Ge4+ is bonded in a 5-coordinate geometry to five Te2- atoms. There are a spread of Ge–Te bond distances ranging from 2.74–3.29 Å. In the fifth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–7°. There are a spread of Ge–Te bond distances ranging from 2.83–3.32 Å. In the sixth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe6 octahedra, edges with two SbTe6 octahedra, edges with four GeTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 5–12°. There are a spread of Ge–Te bond distances ranging from 2.78–3.33 Å. In the seventh Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with six SbTe6 octahedra, edges with three GeTe6 octahedra, edges with three SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Ge–Te bond distances ranging from 2.73–3.42 Å. In the eighth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form distorted GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 11–17°. There are a spread of Ge–Te bond distances ranging from 2.77–3.36 Å. In the ninth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share edges with four GeTe6 octahedra, edges with seven SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. There are a spread of Ge–Te bond distances ranging from 2.93–3.12 Å. In the tenth Ge4+ site, Ge4+ is bonded to five Te2- atoms to form distorted GeTe5 square pyramids that share corners with two GeTe6 octahedra, corners with three SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 7–82°. There are a spread of Ge–Te bond distances ranging from 2.71–3.31 Å. In the eleventh Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, an edgeedge with one GeTe6 octahedra, and edges with eight SbTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Ge–Te bond distances ranging from 2.89–3.25 Å. In the twelfth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with four SbTe6 octahedra, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 5–15°. There are a spread of Ge–Te bond distances ranging from 2.82–3.24 Å. In the thirteenth Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three SbTe6 octahedra, edges with four GeTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 8–12°. There are a spread of Ge–Te bond distances ranging from 2.82–3.34 Å. There are thirteen inequivalent Sb+0.92+ sites. In the first Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with four SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with two SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Sb–Te bond distances ranging from 2.95–3.19 Å. In the second Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with three SbTe6 octahedra, and edges with four GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are a spread of Sb–Te bond distances ranging from 3.02–3.14 Å. In the third Sb+0.92+ site, Sb+0.92+ is bonded in a 6-coordinate geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 2.79–3.57 Å. In the fourth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Sb–Te bond distances ranging from 2.90–3.38 Å. In the fifth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 7–24°. There are a spread of Sb–Te bond distances ranging from 2.82–3.52 Å. In the sixth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 10–16°. There are a spread of Sb–Te bond distances ranging from 2.88–3.35 Å. In the seventh Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, a cornercorner with one GeTe5 square pyramid, edges with four GeTe6 octahedra, and edges with four SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are a spread of Sb–Te bond distances ranging from 2.92–3.30 Å. In the eighth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with two equivalent SbTe6 octahedra, edges with three GeTe6 octahedra, and edges with five SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 11–14°. There are a spread of Sb–Te bond distances ranging from 2.84–3.55 Å. In the ninth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe5 square pyramids, edges with three GeTe6 octahedra, and edges with six SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 12–13°. There are a spread of Sb–Te bond distances ranging from 2.86–3.41 Å. In the tenth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with three SbTe6 octahedra, and edges with five GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 2–15°. There are a spread of Sb–Te bond distances ranging from 2.82–3.39 Å. In the eleventh Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent SbTe6 octahedra, corners with four GeTe6 octahedra, edges with two GeTe6 octahedra, edges with five SbTe6 octahedra, and an edgeedge with one GeTe5 square pyramid. The corner-sharing octahedra tilt angles range from 6–24°. There are a spread of Sb–Te bond distances ranging from 2.85–3.47 Å. In the twelfth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form distorted SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with two GeTe6 octahedra, edges with four SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 5–16°. There are a spread of Sb–Te bond distances ranging from 2.86–3.51 Å. In the thirteenth Sb+0.92+ site, Sb+0.92+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent GeTe6 octahedra, corners with four SbTe6 octahedra, edges with three GeTe6 octahedra, edges with three SbTe6 octahedra, and edges with two GeTe5 square pyramids. The corner-sharing octahedra tilt angles range from 2–15°. There are a spread of Sb–Te bond distances ranging from 2.84–3.38 Å. There are thirty-two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three Ge4+ and two Sb+0.92+ atoms to form distorted TeGe3Sb2 square pyramids that share corners with two TeGe3Sb3 octahedra, corners with four TeGeSb4 square pyramids, an edgeedge with one TeGe3Sb3 octahedra, and edges with three TeGe2Sb3 square pyramids. The corner-sharing octahedral tilt angles are 87°. In the second Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and three Sb+0.92+ atoms. In the third Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to three Ge4+ and one Sb+0.92+ atom. In the fourth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to two Ge4+ and three Sb+0.92+ atoms. In the fifth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and two Sb+0.92+ atoms. In the sixth Te2- site, Te2- is bonded in a distorted rectangular see-saw-like geometry to three Ge4+ and one Sb+0.92+ atom. In the seventh Te2- site, Te2- is bonded to one Ge4+ and four Sb+0.92+ atoms to form distorted TeGeSb4 square pyramids that share corners with five TeGe2Sb3 square pyramids, edges with three TeGe3Sb3 octahedra, and edges with three TeGe2Sb3 square pyramids. In the eighth Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form distorted TeGe2Sb3 square pyramids that share corners with six TeGeSb4 square pyramids, edges with three TeGe3Sb3 octahedra, and an edgeedge with one TeGe2Sb3 square pyramid. In the ninth Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form distorted TeGe2Sb3 square pyramids that share corners with four TeGe2Sb3 square pyramids, edges with two TeGe3Sb3 octahedra, and edges with four TeGeSb4 square pyramids. In the tenth Te2- site, Te2- is bonded in a 4-coordinate geometry to two Ge4+ and two Sb+0.92+ atoms. In the eleventh Te2- site, Te2- is bonded to two Ge4+ and three Sb+0.92+ atoms to form TeGe2Sb3 square pyramids that share corners with four TeGe3Sb3 octahedra, corners with two TeGe2Sb3 square pyramids, and edges with three TeGe2Sb3 square pyramids. The corner-sharing octahedra tilt angles range from 12–14°. In the twelfth Te2- site, Te2- is bonded to four Ge4+ and one Sb+0.92+ atom to form distorted TeGe4Sb square pyramids that share

36 MATERIALS SCIENCE↗