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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Crystal and Electronic Structures of A 2 NaIO 6 Periodate Double Perovskites (A = Sr, Ca, Ba): Candidate Wasteforms for I-129 Immobilization

The synthesis, structure, and thermal stability of the periodate double perovskites A 2 NaIO 6 (A= Ba, Sr, Ca) were investigated in the context of potential application for the immobilization of radioiodine. A combination of X-ray diffraction and neutron diffraction, Raman spectroscopy, and DFT simulations were applied to determine accurate crystal structures of these compounds and understand their relative stability. The compounds were found to exhibit rock-salt ordering of Na and I on the perovskite B-site; Ba 2 NaIO 6 was found to adopt the Fm- 3 m aristotype structure, whereas Sr 2 NaIO 6 and Ca 2 NaIO 6 adopt the P 2 1 / n hettotype structure, characterized by cooperative octahedral tilting. DFT simulations determined the Fm- 3 m and P 2 1 / n structures of Ba 2 NaIO 6 to be energetically degenerate at room temperature, whereas diffraction and spectroscopy data evidence only the presence of the Fm- 3 m phase at room temperature, which may imply an incipient phase transition for this compound. The periodate double perovskites were found to exhibit remarkable thermal stability, with Ba 2 NaIO 6 only decomposing above 1050 °C in air, which is apparently the highest recorded decomposition temperature so far recorded for any iodine bearing compound. As such, these compounds offer some potential for application in the immobilization of iodine-129, from nuclear fuel reprocessing, with an iodine incorporation rate of 25–40 wt%. The synthesis of these compounds, elaborated here, is also compatible with both current conventional and future advanced processes for iodine recovery from the dissolver off-gas.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Molecular Cage Reports on Its Contents: Spectroscopic Signatures of Cryo-Cooled K + - and Ba 2+ -Benzocryptand Complexes

UV photofragment spectroscopy and IR–UV double resonance methods are used to determine the structure and spectroscopic responses of a three-dimensional [2.2.2]-benzocryptand cage to the incorporation of a single K + or Ba 2+ imbedded inside it (labeled as K + -BzCrypt, Ba 2+ -BzCrypt). We studied the isolated ion-cryptand complex under cryo-cooled conditions, brought into the gas phase by nano-electrospray ionization. Incorporation of a phenyl ring in place of the central ethyl group in one of the three N-CH 2 -CH 2 -O-CH 2 -CH 2 -O-CH 2 -CH 2 -N chains provides a UV chromophore whose S 0 –S 1 transition we probe. K + -BzCrypt and Ba 2+ -BzCrypt have their S 0 –S 1 origin transitions at 35,925 and 36,446 cm –1 , respectively, blue-shifted by 174 and 695 cm –1 from that of 1,2-dimethoxybenzene. These origins are used to excite a single conformation of each complex selectively and record their IR spectra using IR–UV dip spectroscopy. The alkyl CH stretch region (2800–3000 cm –1 ) is surprisingly sensitive to the presence and nature of the encapsulated ion. We carried out an exhaustive conformational search of cage conformations for K + -BzCrypt and Ba 2+ -BzCrypt, identifying two conformations (A and B) that lie below all others in energy. Here, we extend our local mode anharmonic model of the CH stretch region to these strongly bound ion-cage complexes to predict conformation-specific alkyl CH stretch spectra, obtaining quantitative agreement with experiment for conformer A, the gas-phase global minimum. The large electrostatic effect of the charge on the O- and N-lone pairs affects the local mode frequencies of the CH 2 groups adjacent to these atoms. The localized CH 2 scissors modes are pushed up in frequency by the adjacent O/N-atoms so that their overtones have little effect on the alkyl CH stretch region. However, the localized CH 2 wags are nearly degenerate and strongly coupled to one another, producing an array of delocalized wag normal modes, whose highest frequency members reach up above 1400 cm –1 . As such, their overtones mix significantly with the CH stretch modes, most notably involving the CH 2 symmetric stretch fundamentals of the central ethyl groups in the all-alkyl chains and the CH stretches adjacent to the N-atoms and antiperiplanar to the nitrogen lone pair.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

The Role of Exciton Binding Energy on LO phonon Broadening and Polaron Formation in (BA) 2 PbI 4 Ruddlesden-Popper Films

The effect of carrier–carrier and carrier–phonon interactions is presented in n = 1 (2D) (BA) 2 PbI 4 Ruddlesden–Popper thin films, and their effect is compared to that of conventional MAPbI 3 . While temperature-dependent photoluminescence shows the well-studied structural phase transitions and evidence of longitudinal optical (LO) phonon scattering in MPbI 3 , the 2D (BA) 2 PbI 4 films produce subtler properties. At low temperatures, evidence of two competing intrinsic exciton transitions is observed (P1 and P3), in addition to several extrinsic transitions attributed to the impurities in the (BA) 2 PbI 4 film. At higher temperatures, (BA) 2 PbI 4 is dominated by the two intrinsic excitons that are attributed to varying degrees of localization caused by deformations of the PbI 4 framework mediated by structural relaxation. Although both exciton complexes are well separated from the continuum (490 meV or greater), their interaction with phonons is quite different. In the case of the more strongly bound complex (P3), the strong excitonic nature and short-range interaction are mediated by the emission of LO phonon replicas. In the case of the exciton with the smaller binding energy (P1), the more extended wavefunction manifests itself in strong carrier–phonon scattering and evidence of large, stable polarons.

2D perovskites↗
DOE OSTI2025

Synthesis, Crystal Structure, and Optical Properties of the Barium meta -Pertechnetate Ba[TcO 4 ] 2

High-quality single crystals of the colorless title compound Ba[ 99 TcO 4 ] 2 were prepared from radioactive, isotope-pure 99 TcO 2 by oxidation with H 2 O 2 in an aqueous ammonia solution and subsequent cation metathesis using an ion-exchange column. Single-crystal X-ray diffraction revealed Ba[TcO 4 ] 2 to crystallize isotopically to Ba[MnO 4 ] 2 in the orthorhombic space group Fddd with the lattice parameters a = 747.34(5) pm, b = 1244.08(7) pm, and c = 1511.23(9) pm for Z = 8. Its crystal structure features [BaO 12 ] 22- icosahedra surrounded by ten [TcO 4 ] - tetrahedra connected via two edges and eight corners. The optical properties of Ba[TcO 4 ] 2 investigated by UV-vis spectroscopy show the broad O 2- → Tc 7+ ligand-to-metal charge transfer (2p → 4d) process within these discrete [TcO 4 ]- anions at an absorption maximum of around 350 nm.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Dopant site-dependent luminescence from rare-earth doped dibarium octafluorohafnate Ba 2 HfF 8 nanocubes for radiation detection

Development of new host materials containing heavy elements for radiation detection is highly desirable. In this work, dibarium octafluorohafnate, Ba 2 HfF 8 , doped with rare-earth ions, was synthesized as cube-shaped nanocrystals via a facile hydrothermal method. The host lattice contains two Ba 2+ crystallographic sites, and dopants on these sites exhibit site-dependent photoluminescence (PL), cathodoluminescence (CL) and X-ray excited radioluminescence (RL) characteristics. Single doping contents were optimized as 25 mol% Tb 3+ and 5 mol% Eu 3+ . In Ba 2 HfF 8 :Tb 3+ –Eu 3+ codoped nanocrystals, preferrable occupation of Eu 3+ and Tb 3+ at two different Ba 2+ sites in the host lattice was observed. The nanocubes exhibited enhanced emissions over micron sized particles. In PL, the presence of Tb3+ ions significantly enhanced the emission intensity of Eu 3+ ions due to energy transfer from the Tb 3+ to Eu 3+ ions, while under high-energy irradiation in CL or RL, Tb 3+ emission was intensified. X-ray induced RL with afterglow in seconds was observed. Finally, it was found that the codoped sample showed higher sensitivity than the singly doped sample, indicating that codoping is an effective strategy to develop a scintillator with this host structure for high-energy radiation detection.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2025

Ba 1−x Sr x FeO 3−δ as an improved oxygen storage material for chemical looping air separation: a computational and experimental study

Chemical looping air separation (CLAS) is a promising technology to generate oxygen-rich gas streams to enable efficient carbon dioxide capture during fossil fuel combustion or gasification. CLAS relies on the capture and release of oxygen from the atmosphere using the redox properties of an oxygen-selective solid oxide carrier. This study investigates the redox characteristics of Ba 1−x Sr x FeO 3−δ (0.0 ≤ x ≤ 0.417, 0.0 ≤ δ ≤ 0.5) using a combination of density functional theory (DFT) calculations and experimental verification using X-ray diffraction, thermogravimetric analysis, and oxygen-temperature-programmed desorption. The DFT computed energies of the Ba 1−x Sr x FeO 3−δ perovskites reveal a composition-dependent transition from hexagonal to cubic phases as the Sr-concentration or oxygen vacancy concentration increases. Oxygen vacancy formation energies of the cubic perovskites are found to be lower than those of their hexagonal counterparts. A low oxygen diffusion barrier of ∼1 eV combined with the thermodynamic preference of Ba 1−x Sr x FeO 3−δ compositions that form in a cubic phase suggests them as promising candidates for oxygen storage applications. The experimental results corroborate this finding by identifying Ba 0.75 Sr 0.25 FeO 3−δ in the cubic phase as an optimal composition offering low-temperature oxygen storage capacities comparable to that of the state-of-the-art Sr 0.75 Ca 0.25 FeO 3−δ perovskite oxygen storage material at 325 °C and 350 °C.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Ultrafast pre-solvated dodecane hole capture and subsequent damage of used nuclear fuel extraction ligands DEHBA, DEH i BA, HONTA, CMPO, HEH[EHP] and TBP

Here, two classes of used nuclear fuel (UNF) extraction ligands, amide (DEHBA, DEH i BA, HONTA) and organophosphorus (CMPO, HEH[EHP], TBP), were selected to study radiation induced damage at picosecond to nanosecond timescale using electron pulse radiolysis in n-dodecane (DD) and supported by quantum chemical calculations. Spectra after radiolysis of 200 mM extraction ligands were recorded in DD/0.3 M DCM. Absorption peaks at 365, 365, 400 and 387 nm in case of DEHBA, DEH i BA, HONTA and CMPO respectively are assigned to triplet excited states. Additional absorption peaks at 420, 460 and 600 nm of DEHBA, DEH i BA and HONTA respectively were identified as due to ligand radical cations. A concentration dependent absorption peak at 600 nm in the case of CMPO was observed and assigned due to a combination of CMPO˙ + , (CMPO) 2 ˙ + and possibly a radical degradation product of CMPO. Weak absorption peaks at 650 and 550 nm in case of HEH[EHP] and TBP were observed and tentatively assigned to their radical cations. A two-component DD˙ + decay in the presence of ligands was observed due to different ligand oxidation mechanisms: ultrafast capture of pre-solvated DD holes and diffusive capture of solvated DD holes. At high extraction ligand concentrations (>100 mM), the majority of DD holes were captured via the ultrafast pre-solvated pathway in <10 ps with C 37 values of 389, 401, 270, 374, 458 and 340 mM for DEHBA, DEHiBA, HONTA, CMPO, HEH[EHP] and TBP respectively. Following ultrafast capture, the remainder of DD holes became solvated and were captured with k = (2.32 ± 0.13), (1.78 ± 0.12), (1.38 ± 0.2), (0.98 ± 0.081), (1.09 ± 0.08) and (1.77 ± 0.046) × 10 10 for DEHBA, DEH i BA, HONTA, CMPO, HEH[EHP] and TBP respectively. Subsequent hole transfer from the extraction ligands˙ + to the low IP solute tri-p-tolylamine (TTA) showed only 4–16% hole transfer, most likely indicating ligand˙ + degradation in 0.9–4.6 ns.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2026

Canted antiferromagnetism and spin reorientation in corner-shared single chain quasi-one-dimensional Ba 2 ⁢FeSe 3

Here, we report the canted antiferromagnetic (AFM) structure together with a spin reorientation in a single chain quasi-one-dimensional (Q-1D) iron chalcogenide Ba 2⁢ FeSe 3 . Ba 2 ⁢FeSe 3 crystallizes in Pnma (No. 62) orthorhombic structure with linear single iron chains consisting of corner-shared distorted FeSe 4 tetrahedra along the 𝑏 axis. Ba 2 ⁢FeSe 3 is a narrow-gap semiconductor and orders AFM below 60 K. Modeling of neutron powder diffraction data reveals a canted AFM ground state of magnetic space group 𝑃⁢𝑎⁢21/𝑐 (BNS No. 14.80) with commensurate propagation vector 𝐤 =(0, $\frac{1}{2}$, 0), where the Fe ion spins are AFM aligned with up-down-up-down (↑−↓−↑−↓) sequence along the Q-1D chain direction of the 𝑏 axis. In the magnetically ordered state, the canting of magnetic moments reorients from the 𝑎⁢𝑐 plane to the 𝑎⁢𝑏 plane below 30 K, with a 10° tilting angle toward the 𝑎 axis, and the magnetic moment does not induce a net moment in either orientation. The density functional theory results indicate that an ↑−↓−↑−↓ AFM state is stabilized along the chain direction. In this work, we elucidate the unique canted AFM of the iron chalcogenide and pave the way for searching exotic physics in Q-1D Ba 2⁢ FeSe 3 .

Gao, Fei [Univ. of Texas at Dallas, Richardson, TX↗
DOE OSTI2020

Evidence of Ba-substitution induced spin-canting in the magnetic Weyl semimetal EuCd 2 As 2

Recently EuCd 2 As 2 was predicted to be a magnetic Weyl semimetal with a lone pair of Weyl nodes generated by A-type antiferromagnetism and protected by a rotational symmetry. However, it was soon discovered that the actual magnetic structure broke the rotational symmetry and internal pressure was later suggested as a route to stabilize the desired magnetic state. In this work we test this prediction by synthesizing a series of Eu 1-x BaxCd 2 As 2 single crystals and studying their structural, magnetic, and transport properties via both experimental techniques and first-principles calculations. We find that small concentrations of Ba (~3%–10%) lead to a small out-of-plane canting of the Eu moment. However, for higher concentrations this effect is suppressed and a nearly in-plane model is recovered. Studying the transport properties we find that all compositions show evidence of an anomalous Hall effect dominated by the intrinsic mechanism as well as large negative magnetoresistances in the longitudinal channel. A nonmonotonic evolution of the transport properties is seen across the series which correlates to the proposed canting suggesting canting may enhance the topological effects. Careful density functional theory calculations using an all-electron approach revise prior predictions finding a purely ferromagnetic ground state with in-plane moments for both the EuCd 2 As 2 and Eu 0.5 Ba 0.5 Cd 2 As 2 compounds, corroborating our experimental findings. This work suggests that Ba substitution can tune the magnetic properties in unexpected ways which correlate to changes in measures of topological properties, encouraging future work to locate the ideal Ba concentration for Eu moment canting.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
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↗
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↗