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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba(HO)2 by Materials Project

Ba(OH)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ba–O bond distances ranging from 2.63–2.81 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to two H1+ and seven O2- atoms. There are one shorter (2.86 Å) and one longer (3.01 Å) Ba–H bond lengths. There are a spread of Ba–O bond distances ranging from 2.61–2.88 Å. In the third Ba2+ site, Ba2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ba–O bond distances ranging from 2.66–3.01 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.98 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.97 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to two Ba2+ and one H1+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one H1+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(MgSi)2 by Materials Project

BaMg2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded in a 8-coordinate geometry to eight equivalent Mg and eight equivalent Si atoms. All Ba–Mg bond lengths are 3.62 Å. All Ba–Si bond lengths are 3.53 Å. Mg is bonded to four equivalent Ba and four equivalent Si atoms to form a mixture of distorted edge, face, and corner-sharing MgBa4Si4 tetrahedra. All Mg–Si bond lengths are 2.79 Å. Si is bonded in a 9-coordinate geometry to four equivalent Ba, four equivalent Mg, and one Si atom. The Si–Si bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(Sn2Ru)3 by Materials Project

Ba(RuSn2)3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ba is bonded in a 8-coordinate geometry to eight Sn atoms. There are four shorter (3.56 Å) and four longer (3.60 Å) Ba–Sn bond lengths. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Ru–Sn bond distances ranging from 2.57–2.76 Å. In the second Ru site, Ru is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Ru–Sn bond distances ranging from 2.63–2.88 Å. There are four inequivalent Sn sites. In the first Sn site, Sn is bonded in a 3-coordinate geometry to three Ru atoms. In the second Sn site, Sn is bonded in a 5-coordinate geometry to two equivalent Ba and three equivalent Ru atoms. In the third Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Ru atoms. In the fourth Sn site, Sn is bonded in a 2-coordinate geometry to two equivalent Ba and three equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(ClO4)2 by Materials Project

Ba(ClO4)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Ba is bonded to twelve O atoms to form distorted BaO12 cuboctahedra that share corners with eight equivalent ClO4 tetrahedra, edges with four equivalent BaO12 cuboctahedra, and edges with two equivalent ClO4 tetrahedra. There are a spread of Ba–O bond distances ranging from 2.94–3.02 Å. There are two inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to one Ba and one Cl atom. The O–Cl bond length is 1.44 Å. In the second O site, O is bonded in a distorted single-bond geometry to two equivalent Ba and one Cl atom. The O–Cl bond length is 1.48 Å. Cl is bonded to four O atoms to form ClO4 tetrahedra that share corners with four equivalent BaO12 cuboctahedra and an edgeedge with one BaO12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(GaH)2 by Materials Project

Ba(GaH)2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ba(GaH)2 sheet oriented in the (0, 0, 1) direction. Ba is bonded in a distorted hexagonal planar geometry to six equivalent H atoms. All Ba–H bond lengths are 2.71 Å. Ga is bonded in a single-bond geometry to one H atom. The Ga–H bond length is 1.69 Å. H is bonded to three equivalent Ba and one Ga atom to form a mixture of distorted corner and edge-sharing HBa3Ga tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2025

U-Pu and Ba-Cs isotopic measurements on Trinitite by laser ablation sampling on the Neoma MC-ICP-MS

In this study we present the results of combined U-Pu and Ba-Cs isotope measurements obtained by laser ablation (LA) sampling of two glassy debris fragments (‘Trinitite’) from the world's first atomic bomb detonation conducted in New Mexico on July 16, 1945. Our primary goal in conducting these measurements was to understand whether examination of the U-Pu and Ba-Cs systematics by direct sampling (e.g. without any chemical separation or purification prior to isotope ratio measurement) could yield meaningful information that would differentiate the Trinitite fragments from glassy material lacking a nuclear fission signature. These measurements were conducted on a ThermoFisher Scientific Neoma multi collector – inductively coupled plasma – mass spectrometer (MC-ICP-MS), which is a relatively new MC-ICP-MS platform, so we also examine the behavior of these isotope systems in standards sampled in solution and via LA. Unsurprisingly, the measurements made on purified solutions of the U, Pu, and Ba isotopic standards produce high precision isotope ratios. Furthermore, this extends to the U-Pu measurements made by LA sampling, with the expected degradation in precision and accuracy related to matrix effects and signal intensity fluctuation. However, the Ba-Cs data acquired by LA is of low precision across all of the matrices examined and bears evidence of complex mass fractionation that will require further investigation to resolve. In total, our results indicate that the observed U-Pu isotope data are of sufficient quality to accurately constrain the U and Pu isotopic composition of glass containing sub-ppm levels of these elements which in turn could be used to differentiate glass containing anthropogenic fission products from natural glass whereas the Ba-Cs LA data cannot be used for this purpose until further methodological refinement is performed.

Ba-Cs↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is Tungsten structured and crystallizes in the cubic Im-3m space group. The structure is three-dimensional. Ba is bonded in a body-centered cubic geometry to eight equivalent Ba atoms. All Ba–Ba bond lengths are 4.36 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is Magnesium structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ba is bonded to twelve equivalent Ba atoms to form a mixture of edge, face, and corner-sharing BaBa12 cuboctahedra. There are six shorter (4.48 Å) and six longer (4.49 Å) Ba–Ba bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Ba is bonded in a 11-coordinate geometry to eleven equivalent Ba atoms. There are a spread of Ba–Ba bond distances ranging from 4.13–4.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is Hg_xSn structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ba is bonded to eight equivalent Ba atoms to form a mixture of edge and corner-sharing BaBa8 hexagonal bipyramids. There are two shorter (3.98 Å) and six longer (4.29 Å) Ba–Ba bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is alpha Po structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba is bonded to six equivalent Ba atoms to form a mixture of corner and edge-sharing BaBa6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (3.94 Å) and two longer (3.98 Å) Ba–Ba bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ba is bonded to five equivalent Ba atoms to form a mixture of edge and corner-sharing BaBa5 trigonal bipyramids. There are two shorter (4.07 Å) and three longer (4.27 Å) Ba–Ba bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is Tungsten structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ba is bonded in a distorted body-centered cubic geometry to eight equivalent Ba atoms. There are a spread of Ba–Ba bond distances ranging from 4.35–4.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba by Materials Project

Ba is Magnesium structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ba is bonded to twelve equivalent Ba atoms to form a mixture of face, edge, and corner-sharing BaBa12 cuboctahedra. There are a spread of Ba–Ba bond distances ranging from 4.36–4.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Locating anionic hydrogen in Ba 3 (Yb,Lu) 2 O 5 H 2 : A combined approach of X-ray diffraction, crystal chemistry, and DFT calculations

By a combination of x-ray diffraction, structural chemistry, and DFT calculations, the presence and location of anionic hydrogen in the two new, layered lanthanide oxyhydrides, Ba 3 Ln 2 O 5 H 2 (Ln ​= ​Yb, Lu) is inferred. Single crystals of the compounds have been synthesized from a molten barium flux with the addition of small amounts of BaH 2 . These phases crystallize in space group I4/mmm (#139, Z ​= ​2) with lattice parameters a ​= ​4.3336(2) Å and c ​= ​22.7197(6) Å, and a ​= ​4.3291(1) Å and c ​= ​22.597(1) Å, respectively. The Ba 3 Ln 2 O 5 H 2 phases comprise two different structural moieties: a perovskite double layer of stoichiometry Ba 2 Ln 2 O 5 H – formed by corner-connected LnO 5 tetragonal bi-pyramids with a terminating hydrogen anion, and a puckered rocksalt-type (BaH) + layer that is stretched along the c-axis. DFT calculations were used to arrive at hydrogen positions that minimize energy and are consistent with structural chemistry principles. Furthermore, the calculations show that the valence band edge is dominated by oxygen 2p orbitals with hydrogen 1s states admixed. The conduction band is formed by barium 5d-orbitals and Lu (Yb) 5d-orbitals. These are characteristics of materials with anionic H – . These new phases are isostructural with the Ba 3 Ln 2 O 5 Cl 2 (Ln ​= ​Gd–Lu) family of compounds with the chlorine atom in the same apical position as the hydrogen atom. Finally, steric effects limit the size of the lanthanide ion for Ba 3 Ln 2 O 5 H 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Quantum Effect on the Ground State of the Triple-Perovskite Ba 3 MNb 2 O 9 (M = Co, Ni, and Mn) with Triangular-Lattice

As the simplest example of geometrical frustration, the two-dimensional triangular lattice antiferromagnet exhibits the mismatch between the lattice geometry and spin-exchange interaction, which has been the subject of intensive studies due to its exotic quantum phenomena. In this work, we performed detailed studies of the magnetic structures and spin wave excitations by neutron powder diffraction and inelastic neutron scattering measurements on the triple-perovskite oxides Ba 3 MNb 2 O 9 (M = Co, Ni, and Mn) with triangular-lattice geometry. The interplay between the frustrated interaction and easy-plane/axis anisotropy gives rise to two magnetic phase transition temperatures for Ba 3 CoNb 2 O 9 (Ba 3 MnNb 2 O 9 ) and only one for Ba 3 NiNb 2 O 9 . The linear spin-wave theory +1/S calculations indicate that both spatial dimensionality and the spin size have a significant impact on the strength of quantum fluctuations, which lead to their different magnetic ground states and exotic physical properties. Moreover, the effects of the thermal fluctuations are presented for Ba 3 NiNb 2 O 9 .

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

Tuning the Radius Ratio to Enhance Thermoelectric Properties in the Zintl Compounds AM 2 Sb 2 (A = Ba, Sr; M = Zn, Cd)

Five novel Zintl phase solid solutions in the Ba 1–x Sr x Zn 2–y Cd y Sb 2 (0 ≤ x ≤ 0.13(1); 0 ≤ y ≤ 0.32(2)) system were successfully synthesized by the molten Pb metal-flux method, and the powder X-ray diffraction and single-crystal X-ray diffraction analyses proved that all five title compounds adopted the BaCu 2 S 2 -type phase having the orthorhombic Pnma space group (Z = 4, Pearson code oP20) with five crystallographically independent atomic sites. The previously studied BaCu 2 S 2 -type antimonides demonstrated a limited tolerance for doping in contrast to the CaAl 2 Si 2 -type antimonides. To understand the relatively narrower phase width and limited dopability of the title BaCu 2 S 2 -type phase than the CaAl 2 Si 2 -type phase in the overall Ba 1–x Sr x Zn 2–y Cd y Sb 2 system, the radius ratio of cations and anionic elements r + /r – for two structure types were thoroughly investigated. For the first time, the r + /r – ratio was identified as a critical factor for the phase selectivity: (1) r + /r – > 1 favored the BaCu 2 S 2 -type phase, and (2) r + /r – < 1 favored the CaAl 2 Si 2 -type phase. Further, we also revealed the structural transformation mechanism from the more widely observed CaAl 2 Si 2 -type phase to the title BaCu 2 S 2 -type phase as the relatively larger cationic elements were introduced to the system. A series of DFT calculations using the three hypothetical models indicated that a resonance peak near EF in the density of states curves was descended from the relatively flat band structure at several special symmetry points rationalizing the enhanced Seebeck coefficients of Ba 0.94(1) Sr 0.06 Zn 1.86(3) Cd 0.14 Sb 2 and Ba 0.96(1) Sr 0.04 Zn 1.68(2) Cd 0.32 Sb 2 . Electron localization function analysis rationalized the correlation between the polarity change of anionic Zn/Cd–Sb bonds and the charge carrier mobility on the anionic frameworks. Temperature-dependent thermoelectric properties were studied for the four title compounds, and the results proved that the Sr and Cd doping in the title Ba 1–x Sr x Zn 2–y Cd y Sb 2 system successfully enhanced the ZT values through the increased Seebeck coefficients and the reduced total thermal conductivities.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Combinatorial screening of crystal structure in Ba-Sr-Mn-Ce perovskite oxides with ABO 3 stoichiometry

ABO 3 oxides with the perovskite-related structures are attracting significant interest due to their promising physical and chemical properties for many applications requiring tunable chemistry, including fuel cells, catalysis, and electrochemical water splitting. Here we report on the crystal structure of the entire family of perovskite oxides with ABO 3 stoichiometry, where A and B are Ba, Sr, Mn, Ce. Given the vast size of this chemically complex material system, exploration for stable perovskite-related structures with respect to its constituent elements and annealing temperature is performed by combinatorial pulsed laser deposition and spatially-resolved characterization of composition and structure. As a result of this high-throughput experimental study, we identify hexagonal perovskite-related polytypic transformation as a function of composition in the Ba 1-x Sr x MnO 3 oxides after annealing at different temperatures. Furthermore, a hexagonal perovskite-related polytype is observed in a narrow composition-temperature range of the Ba 1-x Sr x MnO 3 oxides. In contrast, a tetragonally-distorted perovskite is observed across a wider range of compositions and annealing temperatures in the Sr 1-x Ce x MnO 3 oxides. This structure stability is further enhanced along the Ba 1-x Sr x MnO 3 - Sr 1-x Ce x MnO 3 pseudo-binary tie-line at x=0.25 by increasing Ba-incorporation and annealing temperature. These results indicate that the BaCe x Mn 1-x O 3 - Sr 1-x Ce x MnO 3 pseudo-binary oxide alloys (solid solutions) with tetragonal perovskite structure and broad composition-temperature range of stability are promising candidates for thermochemical water splitting applications.

36 MATERIALS SCIENCE↗