Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Ba(HO)2”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba(HO)2 by Materials Project

Ba(OH)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 2-coordinate geometry to six H1+ and eight O2- atoms. There are a spread of Ba–H bond distances ranging from 2.60–3.19 Å. There are a spread of Ba–O bond distances ranging from 2.76–2.94 Å. In the second Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to three H1+ and seven O2- atoms. There are a spread of Ba–H bond distances ranging from 2.64–2.99 Å. There are a spread of Ba–O bond distances ranging from 2.72–2.93 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to three Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to two equivalent Ba2+ and one O2- atom. The H–O bond length is 0.98 Å. There are four 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 four Ba2+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(HO)2 by Materials Project

Ba(OH)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 12-coordinate geometry to four H1+ and eight O2- atoms. There are a spread of Ba–H bond distances ranging from 2.66–3.05 Å. There are a spread of Ba–O bond distances ranging from 2.74–3.05 Å. In the second Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to three H1+ and seven O2- atoms. There are a spread of Ba–H bond distances ranging from 2.84–2.98 Å. There are a spread of Ba–O bond distances ranging from 2.67–2.89 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 0.99 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 0.99 Å. There are four 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 four Ba2+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
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(HO)2 by Materials Project

Ba(OH)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are five inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 5-coordinate geometry to five H1+ and eight O2- atoms. There are a spread of Ba–H bond distances ranging from 2.86–3.03 Å. There are a spread of Ba–O bond distances ranging from 2.74–3.16 Å. In the second Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to four H1+ and seven O2- atoms. There are a spread of Ba–H bond distances ranging from 2.89–2.99 Å. There are a spread of Ba–O bond distances ranging from 2.64–2.95 Å. In the third Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to two H1+ and seven O2- atoms. There are one shorter (2.88 Å) and one longer (2.98 Å) Ba–H bond lengths. There are a spread of Ba–O bond distances ranging from 2.69–2.85 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ba–O bond distances ranging from 2.63–2.80 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to two equivalent H1+ and nine O2- atoms. There are one shorter (2.84 Å) and one longer (2.86 Å) Ba–H bond lengths. There are a spread of Ba–O bond distances ranging from 2.65–3.26 Å. There are ten inequivalent H1+ sites. In the first 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 second H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.97 Å. In the third 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 fourth 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 fifth 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 sixth 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 seventh H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to two Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to three Ba2+ and one O2- atom. The H–O bond length is 0.98 Å. In the tenth 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. There are ten 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 two Ba2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one H1+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one H1+ atom. In the ninth O2- site, O2- is bonded in a single-bond geometry to four Ba2+ and one H1+ atom. In the tenth 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(H9O5)2 by Materials Project

Ba(HO)10(H2)4 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of sixteen hydrogen molecules and two Ba(HO)10 ribbons oriented in the (0, 1, 0) direction. In each Ba(HO)10 ribbon, Ba2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.49–2.97 Å. There are ten 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 0.98 Å. In the second H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.59 Å) H–O bond length. In the third H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.66 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.01 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to two H1+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to one Ba2+, one H1+, and one O2- atom. The O–O bond length is 1.49 Å. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and one O2- atom. The O–O bond length is 1.30 Å. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Ba2+, one H1+, and one O2- atom. The O–O bond length is 1.42 Å. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one O2- atom. In the sixth O2- site, O2- is bonded in a water-like geometry to one Ba2+ and two H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and one O2- atom. In the ninth O2- site, O2- is bonded in a water-like geometry to one Ba2+ and two H1+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one H1+, and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaP2(HO)4 by Materials Project

Ba(H2PO2)2 crystallizes in the orthorhombic Ccce space group. The structure is two-dimensional and consists of two Ba(H2PO2)2 sheets oriented in the (0, 1, 0) direction. Ba2+ is bonded in a 8-coordinate geometry to eight equivalent O2- atoms. There are four shorter (2.82 Å) and four longer (2.83 Å) Ba–O bond lengths. P1+ is bonded in a distorted tetrahedral geometry to two equivalent H1+ and two equivalent O2- atoms. Both P–H bond lengths are 1.42 Å. Both P–O bond lengths are 1.53 Å. H1+ is bonded in a single-bond geometry to one P1+ atom. O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one P1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Cooperative Ru(4 d )–Ho(4 f ) magnetic ordering and phase coexistence in the 6 H perovskite multiferroic Ba 3 HoRu 2 O 9

We report cooperative magnetic orderings in a 6H-perovskite multiferroic system, Ba 3 HoRu 2 O 9 , via comprehensive neutron powder diffraction measurements. This system undergoes long-range antiferromagnetic ordering at T N1 ~ 50 K with a propagation wave vector of K 1 = (0.5 0 0), a transition temperature much higher than the previously reported one at ~10 K (T N2 ). Both Ru and Ho-moments order simultaneously below T N1 , followed by spin-reorientations at lower temperatures, demonstrating strong Ru(4d)-Ho(4f) magnetic correlation. Below T N1 another magnetic phase with a propagation wave vector K 2 = (0.25 0.25 0) emerges and coexists with the one associated with K 1 , which is rarely observed and suggests complex magnetism due to phase competition in the magnetic ground state. Here, we argue that the exchange-striction arising from the up-up-down-down spin structure associated with K 2 below T N2 may be responsible for the small ferroelectric polarization reported previously in this compound.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Magnetic and Magnetocaloric Properties of the A 2 LnSbO 6 Lanthanide Oxides on the Frustrated fcc Lattice

Frustrated lanthanide oxides are promising candidates for cryogen-free magnetic refrigeration due to their suppressed ordering temperatures and high magnetic moments. While much attention has been paid to the garnet and pyrochlore lattices, the magnetocaloric effect in frustrated face-centered cubic (fcc) lattices remains relatively unexplored. We previously showed that the frustrated fcc double perovskite Ba 2 GdSbO 6 is a top-performing magnetocaloric material (per mol Gd) because of its small nearest-neighbor interaction between spins. Here we investigate different tuning parameters to maximize the magnetocaloric effect in the family of fcc lanthanide oxides, A 2 LnSbO 6 (A = {Ba 2+ , Sr 2+ } and Ln = {Nd 3+ , Tb 3+ , Gd 3+ , Ho 3+ , Dy 3+ , Er 3+ }), including chemical pressure via the A site cation and the magnetic ground state via the lanthanide ion. Bulk magnetic measurements indicate a possible trend between magnetic short-range fluctuations and the field-temperature phase space of the magnetocaloric effect, determined by whether an ion is a Kramers or a non-Kramers ion. We report for the first time on the synthesis and magnetic characterization of the Ca 2 LnSbO 6 series with tunable site disorder that can be used to control the deviations from Curie–Weiss behavior. Taken together, these results suggest fcc lanthanide oxides as tunable systems for magnetocaloric design.

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

Materials Data on Ba(HoTe2)2 by Materials Project

Ba(HoTe2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of Ba–Te bond distances ranging from 3.56–3.75 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six Te2- atoms to form a mixture of edge and corner-sharing HoTe6 octahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of Ho–Te bond distances ranging from 3.05–3.13 Å. In the second Ho3+ site, Ho3+ is bonded to six Te2- atoms to form a mixture of edge and corner-sharing HoTe6 octahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of Ho–Te bond distances ranging from 3.05–3.12 Å. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to two equivalent Ba2+ and three Ho3+ atoms to form a mixture of distorted edge and corner-sharing TeBa2Ho3 trigonal bipyramids. In the second Te2- site, Te2- is bonded to two equivalent Ba2+ and three equivalent Ho3+ atoms to form a mixture of distorted edge and corner-sharing TeBa2Ho3 square pyramids. In the third Te2- site, Te2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Ho3+ atoms. In the fourth Te2- site, Te2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three equivalent Ho3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(HoS2)2 by Materials Project

Ba(HoS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.21–3.39 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing HoS6 octahedra. The corner-sharing octahedra tilt angles range from 48–60°. There are one shorter (2.69 Å) and five longer (2.76 Å) Ho–S bond lengths. In the second Ho3+ site, Ho3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing HoS6 octahedra. The corner-sharing octahedra tilt angles range from 48–60°. There are a spread of Ho–S bond distances ranging from 2.71–2.77 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Ho3+ atoms. In the second S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Ho3+ atoms to form a mixture of distorted edge and corner-sharing SBa2Ho3 square pyramids. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Ho3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Ho3+ atoms to form a mixture of distorted edge and corner-sharing SBa2Ho3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaHo(CoO3)2 by Materials Project

BaHo(CoO3)2 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, corners with eight equivalent HoO12 cuboctahedra, faces with two equivalent HoO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, and faces with eight equivalent CoO6 octahedra. There are four shorter (2.70 Å) and eight longer (2.97 Å) Ba–O bond lengths. Ho3+ is bonded to twelve O2- atoms to form HoO12 cuboctahedra that share corners with four equivalent HoO12 cuboctahedra, corners with eight equivalent BaO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four equivalent HoO12 cuboctahedra, and faces with eight equivalent CoO6 octahedra. There are eight shorter (2.53 Å) and four longer (2.70 Å) Ho–O bond lengths. Co+3.50+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, faces with four equivalent BaO12 cuboctahedra, and faces with four equivalent HoO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are a spread of Co–O bond distances ranging from 1.92–2.01 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ho3+ and two equivalent Co+3.50+ atoms. In the second O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Co+3.50+ atoms to form a mixture of edge and corner-sharing OBa4Co2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, two equivalent Ho3+, and two equivalent Co+3.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Tl(HO)7 by Materials Project

Ba2Tl(HO)7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ba2+ is bonded in a 2-coordinate geometry to one H1+ and eight O2- atoms. The Ba–H bond length is 2.87 Å. There are a spread of Ba–O bond distances ranging from 2.69–3.06 Å. Tl3+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Tl–O bond distances ranging from 2.21–2.40 Å. There are four 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 1.00 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 0.98 Å. In the fourth 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 four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+, one Tl3+, and one H1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+, one Tl3+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+, one Tl3+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to two equivalent Ba2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ho(RuO4)3 by Materials Project

Ba4Ho(RuO4)3 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent HoO6 octahedra, and faces with four equivalent RuO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.90–3.13 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, a faceface with one HoO6 octahedra, and faces with six RuO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.98–3.11 Å. Ho3+ is bonded to six equivalent O2- atoms to form HoO6 octahedra that share corners with six equivalent RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Ho–O bond lengths are 2.21 Å. There are two inequivalent Ru+4.33+ sites. In the first Ru+4.33+ site, Ru+4.33+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent HoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (1.95 Å) and three longer (2.06 Å) Ru–O bond lengths. In the second Ru+4.33+ site, Ru+4.33+ is bonded to six equivalent O2- atoms to form RuO6 octahedra that share corners with six equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with two equivalent RuO6 octahedra. All Ru–O bond lengths are 2.03 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ho3+, and one Ru+4.33+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ru+4.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Zn(HO)6 by Materials Project

Ba2Zn(HO)6 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Ba2Zn(HO)6 sheet oriented in the (-1, 0, 2) direction. Ba2+ is bonded in a 6-coordinate geometry to two H1+ and four O2- atoms. There are one shorter (2.84 Å) and one longer (2.96 Å) Ba–H bond lengths. There are a spread of Ba–O bond distances ranging from 2.50–2.79 Å. Zn2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.82 Å) and two longer (2.57 Å) Zn–O bond lengths. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted water-like geometry to one Ba2+ and one H1+ atom. The H–H bond length is 0.76 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one H1+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Ba2+, one H1+, and one O2- atom. The O–O bond length is 1.50 Å. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Zn2+, and one O2- atom. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to two equivalent Ba2+ and one Zn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2HoTaO6 by Materials Project

Ba2HoTaO6 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with four equivalent HoO6 octahedra, and faces with four equivalent TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.90–3.14 Å. Ho3+ is bonded to six O2- atoms to form HoO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–9°. All Ho–O bond lengths are 2.25 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six equivalent HoO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–9°. All Ta–O bond lengths are 2.02 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+, one Ho3+, and one Ta5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+, one Ho3+, and one Ta5+ atom.

36 MATERIALS SCIENCE↗
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↗
NASA NTRS1987

Superconductivity above 90 K in the square-planar compound system ABa2Cu3O(6 + x) with A = Y, La, Nd, Sm, Eu, Gd, Ho, Er, and Lu

Superconductivity has been found in the 90-K range in ABa2Cu3O(6 + x) with A = La, Nd, Sm, Eu, Gd, Ho, Er, and Lu in addition to Y. The results suggest that the unique square-planar Cu atoms, each surrounded by four or six oxygen atoms, are crucial to the superconductivity of oxides in general. In particular, the high Tc of ABa2Cu3O(6 + x) is attributed mainly to the quasi-two-dimensional assembly of the CuO2-Ba-CuO(2 + x)Ba-CuO2 layers sandwiched between two A layers, with particular emphasis in the CuO(2 + x) layers. Higher-Tc oxides are predicted for compounds with bigger assemblies of CuO2 layers coupled by Ba layers.

Hor, P. H.↗
DOE OSTI2020

Materials Data on Ba3Ho(BO3)3 by Materials Project

Ba3Ho(BO3)3 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–2.96 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.68–2.99 Å. In the third Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are six shorter (2.80 Å) and three longer (3.05 Å) Ba–O bond lengths. In the fourth Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are six shorter (2.81 Å) and three longer (2.95 Å) Ba–O bond lengths. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in an octahedral geometry to six O2- atoms. There are three shorter (2.23 Å) and three longer (2.28 Å) Ho–O bond lengths. In the second Ho3+ site, Ho3+ is bonded in an octahedral geometry to six O2- atoms. All Ho–O bond lengths are 2.25 Å. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.39 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.39 Å) and one longer (1.40 Å) B–O bond length. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.40 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one B3+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ho3+, and one B3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ho3+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+, one Ho3+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+, one Ho3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one B3+ atom.

36 MATERIALS SCIENCE↗