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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Magnetic excitations in the square-lattice iridate Ba 2 ⁢IrO 4

Here, we report a resonant inelastic x-ray scattering investigation of ultrathin epitaxial films of Ba 2 ⁢IrO 4 , and compare their low-energy magnetic and spin-orbit excitations to those of their sister compound Sr 2 ⁢IrO 4 . Due to the 180° Ir-O-Ir bond, the bandwidth of the magnon and spin orbiton is significantly larger in Ba 2⁢ IrO 4 , making it difficult to describe these two types of excitations as separate well-defined quasiparticles. Both types of excitations are found to be quite sensitive to the effect of epitaxial strain. In addition, we find that the f-level inversion observed in Sr 2 ⁢IrO 4 is absent in Ba 2 ⁢IrO 4 , as predicted in recent theoretical studies. Our results illustrate that the magnetic properties of Ba 2 ⁢IrO 4 are substantially different from those of Sr 2 ⁢IrO 4 , suggesting that these materials need to be examined more carefully with electron itinerancy taken into account.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Synthesis and characterization of the novel breathing pyrochlore compound Ba 3 ⁢Tm 2⁢ Zn 5⁢ O 11

In this study, a novel material from the rare-earth based breathing pyrochlore family, Ba 3 ⁢Tm 2 ⁢Zn 5 ⁢O 11 , was successfully synthesized. Powder x-ray diffraction and high-resolution powder neutron diffraction confirmed phase purity and the $F\bar4$3⁢𝑚 breathing pyrochlore crystal structure, while thermogravimetric analysis revealed incongruent melting behavior compared to its counterpart, Ba 3 ⁢Yb 2⁢ Zn 5⁢ O 11 . High-quality single crystals of Ba 3 ⁢Tm 2 ⁢Zn 5 ⁢O 11 were grown using the traveling solvent floating zone technique and assessed using Laue x-ray diffraction and single crystal x-ray diffraction. Further, thermodynamic characterization indicated paramagnetic behavior down to 0.05 K, and inelastic neutron scattering measurements identified distinct dispersionless crystal electric field energy bands, with the fitted crystal electric field model predicting a single-ion singlet ground state and an energy gap of ∼9 meV separating it from the first excited (singlet) state. Additional low-energy excitation studies on single crystals revealed dispersionless bands at 0.8 and 1 meV. Computed phonon dispersions from first-principles calculations ruled out phonons as the origin of these modes, further illustrating the puzzling and unique properties of Ba 3 ⁢Tm⁢ 2 Zn 5 ⁢O 11 .

36 MATERIALS SCIENCE↗
DOE OSTI2024

Assessing Carrier Mobility, Dopability, and Defect Tolerance in the Chalcogenide Perovskite Ba Zr S 3

The chalcogenide perovskite Ba Zr S 3 has attracted much attention as a promising solar absorber for thin-film photovoltaics. Here we use first-principles calculations to evaluate its carrier transport and defect properties. We find that Ba Zr S 3 has a phonon-limited electron mobility of 37 cm 2 / V s, which is comparable to that in halide perovskites, but lower hole mobility of 11 cm 2 / V s. The defect computations indicate that Ba Zr S 3 is intrinsically n -type due to shallow sulfur vacancies, but that strong compensation by sulfur vacancies will prevent attempts to make it p -type. We also establish that Ba Zr S 3 shows some degree of defect tolerance, presenting only few low formation energy, deep intrinsic defects. Among the deep defects, sulfur interstitials are the dominant nonradiative recombination centers but exhibit a moderate capture coefficient. Our work highlights the material’s intrinsic limitations in carrier mobility and p -type doping, and suggests focusing on suppressing the formation of sulfur interstitials to achieve longer carrier lifetime. Published by the American Physical Society 2024

Yuan, Zhenkun (ORCID:0000000272005973)↗
DOE OSTI2024

Thermodynamic Modeling of Point Defects in Triple Conducting Perovskite Ba 0.95 La 0.05 FeO 3- $_δ$ with Incorporation of the Hydride Defect Formation Reaction for Solid Oxide Cells

Distinct from the proton defect, the hydride defect species may be present in certain perovskite materials in reducing environments such as in fuel electrodes of solid oxide cells (SOCs) or on the reducing side of ceramic membranes. A generalized defect thermodynamic model was developed for the triple-conducting perovskites (La,Ba)Fe 1-x M x O 3-δ (M = Y and Zr) to allow inclusion of the hydride defect formation reaction in addition to the other three main defect reactions, namely, the oxygen vacancy formation, hydration, and charge disproportionation reactions. This comprehensive defect model also allows the incorporation of polynomial functional forms of oxygen nonstoichiometry δ to describe the defect reaction energies and entropies and to enable refinements of the defect reaction equilibrium constants in the defect thermodynamic analysis. As a first step, the developed model is applied to the Ba 0.95 La 0.05 FeO 3-δ material as an illustrative system to obtain its Brouwer diagrams with both the proton and hydride defects in relevant SOC conditions, particularly for more reducing environments. In conclusion, the results provide direct guidance on the influence of electronic and ionic defect concentrations upon thermodynamic properties and ultimately on the performance of Ba 0.95 La 0.05 FeO 3-δ and potentially other (La,Ba)Fe 1-x M x O 3-δ perovskite materials involved in SOC applications.

25 ENERGY STORAGE↗
DOE OSTI2020

Crystalline Silicotitanate Batch Contact Testing with Ba, Ca, Pb, and Sr

Washington River Protection Solutions is working to support initial production of immobilized low-activity waste (LAW) by feeding Hanford tank supernate from tank farms to the Hanford Waste Treatment and Immobilization Plant (WTP) LAW Facility. This goal incorporates the design of a Tank Side Cesium Removal system, which filters tank waste supernate to remove suspended solids and then removes Cs by processing it through crystalline silicotitanate (CST) ion exchange media manufactured by Honeywell UOP, LLC. The 137 Cs-depleted product is intended to be sent to the WTP for vitrification. Processing of actual tank waste supernate showed effectively complete uptake of Sr and Ba by CST and significant uptake of Ca. Further, Campbell et al. (2019) analyzed CST post-column testing and found significant (>1E-2 mmoles/g) uptake of Ca and Pb along with some Ba, Cd, Fe, Sr, and U. This led to concern that selected metals, particularly the +2 cations, Ca, Sr, Ba, and Pb may be consuming Cs exchange sites and possibly reducing CST capacity for Cs. Exchange of +2 cations was assumed to be associated with the M(OH) + species for the metal (M) ion in the caustic solution. A series of batch contact testing was conducted to evaluate the exchange behavior of Ba, Ca, Pb, and Sr onto CST. The Cs exchange behavior was also tested as a benchmark for direct comparisons. The CST was provided in the sodium form by Honeywell UOP, as IONSIV TM R9140-B, Lot 2002009604, 18 x 50 mesh. A <30-mesh aliquot was collected to match the sieve fraction expected for use in upcoming small column test configurations. Kinetic exchange rate and isotherms were measured at metal concentrations benchmarked from the AP-107 tank waste feed composition and as limited by the metal solubility in the alkaline solution. Two simplified matrices were tested: 1) 1.0 M NaOH/4.6 M NaNO 3 and 2) 0.1 M NaOH/5.5 M NaNO 3 ; these matrices represented the expected 5.6 M Na concentration of process feed and served to address the hydroxide concentration effect on exchange behavior.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

M + (M=Ca, Ba) Cations Bound to Molecular Cavities: A New Strategy for Incorporating Molecular Quantum States into Quantum Information

This project pursued a novel strategy for incorporating multiple qubits per ion into ion-trap based quantum computing (ITQC) involving Ca + and Ba + . By forming molecular complexes of these cations with molecular-scale cages, we hypothesized that molecular energy levels could be incorporated into quantum computing while retaining key properties of the atomic ions intact. We experimented with a variety of molecular cages and found that Na + , K + , Rb + , Ca 2+ , Sr 2+ , and Ba 2+ could be captured and brought into the gas phase efficiently by imbedding them inside [2.2.2]-benzocryptand. IR and UV spectra of these cage complexes are sensitive to the size and charge state of the ion, reporting on the structures and binding properties of the cage complexes. UV photofragmentation of the Ba 2+ -Acetate -1 -BzCrypt complex produces Ba + -BzCrypt, the complex targeted for exploration in the original hypothesis. Follow-on funding is needed to pursue the spectroscopy of this complex as a target for ITQC.

74 ATOMIC AND MOLECULAR PHYSICS↗
NASA NTRS1984

Theoretical electric quadrupole transition probabilities for Ca, Sr and Ba

The 1D-1S quadrupole transition probabilities for Ca, Sr and Ba have been computed using extended GTO and STO valence basis sets and configuration-interaction wavefunctions that include the important core-valence correlation effects. For Ba and Sr, the relativistic contraction of the core orbitals was accounted for in the GTO calculations by a relativistic effective-core potential. The computed Einstein coefficient for Ca of 39.6/s is in excellent agreement with the recent experimental value of 40 + or - 8/s. The best Einstein coefficients for Sr (44.7/s) and Ba (2.98/s) imply increasing quadrupole line strengths down the column. Relativistic effects substantially increase the quadrupole Einstein coefficient for Ba.

Bauschlicher, C. W., Jr.↗
NASA NTRS1989

Preparation of high T(c) Tl-Ba-Ca-Cu-O thin films by pulsed laser evaporation and Tl2O3 vapor processing

Tl-Ba-Ca-Cu-O superconducting thin films with zero-resistance temperatures up to 115 K have been prepared using a Tl2O3 vapor process on Ba-Ca-Cu-O precursor thin films. The Ba-Ca-Cu-O thin films were made by laser deposition on Y-stabilized ZrO2 substrates. This technique minimizes problems caused by the toxicity of Tl2O3, and its subsequent decomposition to the volatile and toxic Tl2O upon heating. Therefore, it may have practical application in the fabrication of high T(c) Tl-Ba-Ca-Cu-O superconducting thin-film devices.

Johs, B.↗
NASA NTRS1991

Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets

The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed.

Derochemont, L. Pierre↗
DOE OSTI2020

Materials Data on Ba(PIr)2 by Materials Project

BaIr2P2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded in a body-centered cubic geometry to eight equivalent P atoms. All Ba–P bond lengths are 3.40 Å. Ir is bonded to four equivalent P atoms to form a mixture of distorted edge and corner-sharing IrP4 tetrahedra. All Ir–P bond lengths are 2.38 Å. P is bonded in a 8-coordinate geometry to four equivalent Ba and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(InSe2)2 by Materials Project

BaIn2Se4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Ba–Se bond distances ranging from 3.41–3.50 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.42 Å) and four longer (3.48 Å) Ba–Se bond lengths. In the third Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.43 Å) and four longer (3.47 Å) Ba–Se bond lengths. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.59–2.66 Å. In the second In3+ site, In3+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.59–2.66 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two Ba2+ and two In3+ atoms to form a mixture of distorted edge and corner-sharing SeBa2In2 trigonal pyramids. In the second Se2- site, Se2- is bonded to two Ba2+ and two In3+ atoms to form a mixture of distorted edge and corner-sharing SeBa2In2 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ba2+ and two equivalent In3+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ba2+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(InS2)2 by Materials Project

BaIn2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.29–3.38 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.30 Å) and four longer (3.35 Å) Ba–S bond lengths. In the third Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.31 Å) and four longer (3.34 Å) Ba–S bond lengths. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing InS4 tetrahedra. There are a spread of In–S bond distances ranging from 2.45–2.53 Å. In the second In3+ site, In3+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing InS4 tetrahedra. There are a spread of In–S bond distances ranging from 2.45–2.53 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two Ba2+ and two In3+ atoms. In the second S2- site, S2- is bonded to two Ba2+ and two In3+ atoms to form a mixture of distorted corner and edge-sharing SBa2In2 trigonal pyramids. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Ba2+ and two equivalent In3+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Ba2+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(MnGe)2 by Materials Project

BaMn2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded in a distorted body-centered cubic geometry to eight equivalent Ge atoms. All Ba–Ge bond lengths are 3.53 Å. Mn is bonded to four equivalent Ge atoms to form a mixture of distorted edge and corner-sharing MnGe4 tetrahedra. All Mn–Ge bond lengths are 2.48 Å. Ge is bonded in a 4-coordinate geometry to four equivalent Ba and four equivalent Mn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(GeP)2 by Materials Project

Ba(GeP)2 crystallizes in the tetragonal P4_2mc space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. There are four shorter (3.44 Å) and four longer (3.53 Å) Ba–P bond lengths. In the second Ba2+ site, Ba2+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. There are four shorter (3.35 Å) and four longer (3.46 Å) Ba–P bond lengths. There are two inequivalent Ge2+ sites. In the first Ge2+ site, Ge2+ is bonded in a water-like geometry to two equivalent P3- atoms. Both Ge–P bond lengths are 2.34 Å. In the second Ge2+ site, Ge2+ is bonded in a bent 120 degrees geometry to two equivalent P3- atoms. Both Ge–P bond lengths are 2.35 Å. P3- is bonded in a 6-coordinate geometry to four Ba2+ and two Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(GeAs)2 by Materials Project

Ba(GeAs)2 crystallizes in the tetragonal P4_2mc space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a body-centered cubic geometry to eight equivalent As3- atoms. There are four shorter (3.54 Å) and four longer (3.61 Å) Ba–As bond lengths. In the second Ba2+ site, Ba2+ is bonded in a body-centered cubic geometry to eight equivalent As3- atoms. There are four shorter (3.42 Å) and four longer (3.49 Å) Ba–As bond lengths. There are two inequivalent Ge2+ sites. In the first Ge2+ site, Ge2+ is bonded in a water-like geometry to two equivalent As3- atoms. Both Ge–As bond lengths are 2.46 Å. In the second Ge2+ site, Ge2+ is bonded in a bent 120 degrees geometry to two equivalent As3- atoms. Both Ge–As bond lengths are 2.46 Å. As3- is bonded in a 6-coordinate geometry to four Ba2+ and two Ge2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(BiS2)2 by Materials Project

Ba(BiS2)2 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.19–3.48 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.21–3.57 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing BiS6 octahedra. The corner-sharing octahedral tilt angles are 58°. There are a spread of Bi–S bond distances ranging from 2.71–3.01 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form a mixture of distorted edge and corner-sharing BiS6 square pyramids. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Bi–S bond distances ranging from 2.59–3.56 Å. In the third Bi3+ site, Bi3+ is bonded to six S2- atoms to form a mixture of distorted edge and corner-sharing BiS6 octahedra. There are a spread of Bi–S bond distances ranging from 2.57–3.48 Å. In the fourth Bi3+ site, Bi3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing BiS6 octahedra. There are a spread of Bi–S bond distances ranging from 2.65–3.02 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to one Ba2+ and five Bi3+ atoms to form distorted SBaBi5 octahedra that share corners with two equivalent SBaBi5 octahedra, corners with four SBa2Bi3 trigonal bipyramids, edges with seven SBaBi5 octahedra, and edges with three SBa2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the second S2- site, S2- is bonded in a distorted trigonal planar geometry to three equivalent Bi3+ atoms. In the third S2- site, S2- is bonded to two Ba2+ and three Bi3+ atoms to form distorted SBa2Bi3 trigonal bipyramids that share corners with four SBaBi5 octahedra, corners with three equivalent SBa2Bi3 square pyramids, corners with two equivalent SBa2Bi3 trigonal bipyramids, edges with three SBaBi5 octahedra, and edges with four SBa2Bi3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 10–48°. In the fourth S2- site, S2- is bonded to two equivalent Ba2+ and three Bi3+ atoms to form distorted SBa2Bi3 trigonal bipyramids that share corners with four equivalent SBaBi5 octahedra, corners with two equivalent SBa2Bi3 square pyramids, corners with two equivalent SBa4Bi trigonal bipyramids, an edgeedge with one SBaBi5 octahedra, edges with three equivalent SBa2Bi3 square pyramids, and edges with five SBa2Bi3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 6–41°. In the fifth S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Ba2+ and one Bi3+ atom. In the sixth S2- site, S2- is bonded to one Ba2+ and five Bi3+ atoms to form distorted SBaBi5 octahedra that share corners with two equivalent SBaBi5 octahedra, corners with five SBa2Bi3 trigonal bipyramids, edges with five SBaBi5 octahedra, edges with two equivalent SBa2Bi3 square pyramids, and edges with five SBa2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 5°. In the seventh S2- site, S2- is bonded to four Ba2+ and one Bi3+ atom to form distorted SBa4Bi trigonal bipyramids that share a cornercorner with one SBaBi5 octahedra, corners with two equivalent SBa2Bi3 square pyramids, corners with two equivalent SBa2Bi3 trigonal bipyramids, edges with four SBaBi5 octahedra, an edgeedge with one SBa2Bi3 square pyramid, and edges with five SBa2Bi3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 4°. In the eighth S2- site, S2- is bonded to two equivalent Ba2+ and three Bi3+ atoms to form distorted SBa2Bi3 square pyramids that share corners with seven SBa2Bi3 trigonal bipyramids, edges with two equivalent SBaBi5 octahedra, edges with two equivalent SBa2Bi3 square pyramids, and edges with four SBa2Bi3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(SbS2)2 by Materials Project

Ba(SbS2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.19–3.44 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine S2- atoms. There are a spread of Ba–S bond distances ranging from 3.28–3.72 Å. There are four inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are a spread of Sb–S bond distances ranging from 2.46–2.84 Å. In the second Sb3+ site, Sb3+ is bonded to five S2- atoms to form edge-sharing SbS5 square pyramids. There are a spread of Sb–S bond distances ranging from 2.50–2.97 Å. In the third Sb3+ site, Sb3+ is bonded in a rectangular see-saw-like geometry to four S2- atoms. There are a spread of Sb–S bond distances ranging from 2.44–2.98 Å. In the fourth Sb3+ site, Sb3+ is bonded in a 4-coordinate geometry to three S2- atoms. There are a spread of Sb–S bond distances ranging from 2.48–2.51 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to four Ba2+ and one Sb3+ atom to form distorted SBa4Sb trigonal bipyramids that share corners with four equivalent SBa4Sb trigonal bipyramids, a cornercorner with one SBa2Sb2 trigonal pyramid, and edges with two equivalent SBa2Sb2 trigonal pyramids. In the second S2- site, S2- is bonded to two equivalent Ba2+ and two Sb3+ atoms to form distorted SBa2Sb2 trigonal pyramids that share a cornercorner with one SBa4Sb trigonal bipyramid, corners with two equivalent SBa2Sb2 trigonal pyramids, and edges with two equivalent SBa4Sb trigonal bipyramids. In the third S2- site, S2- is bonded in a 5-coordinate geometry to four Ba2+ and one Sb3+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to two Ba2+ and three Sb3+ atoms. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to one Ba2+ and two Sb3+ atoms. In the sixth S2- site, S2- is bonded in a distorted see-saw-like geometry to two Ba2+ and two Sb3+ atoms. In the seventh S2- site, S2- is bonded in a distorted T-shaped geometry to three Sb3+ atoms. In the eighth S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Sb3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(AuF4)2 by Materials Project

Ba(AuF4)2 crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve F1- atoms to form distorted corner-sharing BaF12 cuboctahedra. There are a spread of Ba–F bond distances ranging from 2.82–3.15 Å. In the second Ba2+ site, Ba2+ is bonded to eight F1- atoms to form distorted corner-sharing BaF8 hexagonal bipyramids. There are four shorter (2.65 Å) and four longer (2.80 Å) Ba–F bond lengths. Au3+ is bonded in a rectangular see-saw-like geometry to four F1- atoms. There are a spread of Au–F bond distances ranging from 1.95–1.97 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 1-coordinate geometry to one Ba2+ and one Au3+ atom. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two Ba2+ and one Au3+ atom. In the third F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and one Au3+ atom. In the fourth F1- site, F1- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and one Au3+ atom.

36 MATERIALS SCIENCE↗