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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ho5B2(O2F3)3 by Materials Project

Ho5B2(O2F3)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 9-coordinate geometry to four O2- and five F1- atoms. There are a spread of Ho–O bond distances ranging from 2.33–2.56 Å. There are a spread of Ho–F bond distances ranging from 2.21–2.41 Å. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to three O2- and five F1- atoms. There are a spread of Ho–O bond distances ranging from 2.31–2.41 Å. There are a spread of Ho–F bond distances ranging from 2.23–2.51 Å. In the third Ho3+ site, Ho3+ is bonded in a 9-coordinate geometry to four O2- and five F1- atoms. There are two shorter (2.34 Å) and two longer (2.36 Å) Ho–O bond lengths. There are a spread of Ho–F bond distances ranging from 2.28–2.64 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.38–1.40 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Ho3+ and one B3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Ho3+ and one B3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Ho3+ and one B3+ atom. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the fifth F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Ho3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho3TaO7 by Materials Project

Ho3TaO7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra and corners with two TaO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Ho–O bond distances ranging from 2.16–2.40 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra and corners with two TaO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Ho–O bond distances ranging from 2.17–2.41 Å. In the third Ho3+ site, Ho3+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.15–2.72 Å. In the fourth Ho3+ site, Ho3+ is bonded in a 5-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.15–2.80 Å. In the fifth Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.13–2.71 Å. In the sixth Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.13–2.68 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to four O2- atoms to form distorted TaO4 tetrahedra that share corners with two HoO6 octahedra and a cornercorner with one TaO5 tetrahedra. The corner-sharing octahedra tilt angles range from 60–63°. There is two shorter (1.90 Å) and two longer (1.91 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 tetrahedra that share corners with two HoO6 octahedra and a cornercorner with one TaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of Ta–O bond distances ranging from 1.90–2.47 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form corner-sharing OHo4 tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ho3+ atoms. In the third O2- site, O2- is bonded to four Ho3+ atoms to form corner-sharing OHo4 tetrahedra. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Ho3+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ho3+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Ta5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2VPO8 by Materials Project

Ho2VPO8 is Zircon-derived structured and crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.37 Å) and four longer (2.39 Å) Ho–O bond lengths. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.26 Å) and four longer (2.44 Å) Ho–O bond lengths. V5+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All V–O bond lengths are 1.73 Å. P5+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All P–O bond lengths are 1.56 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Ho3+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one V5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho3Si3O10F by Materials Project

Ho3Si3O10F crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Ho–O bond distances ranging from 2.29–2.58 Å. The Ho–F bond length is 2.24 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- and one F1- atom to form HoO6F pentagonal bipyramids that share corners with six SiO4 tetrahedra. There are a spread of Ho–O bond distances ranging from 2.23–2.46 Å. The Ho–F bond length is 2.39 Å. In the third Ho3+ site, Ho3+ is bonded in a 6-coordinate geometry to six O2- and one F1- atom. There are a spread of Ho–O bond distances ranging from 2.25–2.73 Å. The Ho–F bond length is 2.29 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent HoO6F pentagonal bipyramids and a cornercorner with one SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent HoO6F pentagonal bipyramids and corners with two SiO4 tetrahedra. There is two shorter (1.63 Å) and two longer (1.66 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent HoO6F pentagonal bipyramids and a cornercorner with one SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ho3+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ho3+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Si4+ atom. F1- is bonded in a 3-coordinate geometry to three Ho3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoTaO4 by Materials Project

HoTaO4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.30–2.46 Å. Ta5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ta–O bond distances ranging from 1.88–2.36 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2WO6 by Materials Project

Ho2WO6 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are four inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.24–2.78 Å. In the second Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.22–2.44 Å. In the third Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.23–2.74 Å. In the fourth Ho3+ site, Ho3+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.21–2.60 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded in a distorted octahedral geometry to six O2- atoms. There are a spread of W–O bond distances ranging from 1.87–2.15 Å. In the second W6+ site, W6+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of W–O bond distances ranging from 1.92–2.02 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one W6+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ho3+ and one W6+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one W6+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one W6+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ho3+ and one W6+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one W6+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ho3+ and one W6+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Ho3+ and one W6+ atom. In the ninth O2- site, O2- is bonded in a distorted tetrahedral geometry to three Ho3+ and one W6+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ and one W6+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ and one W6+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Machine learning-accelerated discovery of iron cobalt phosphides as rare-earth-free magnets

Here, the discovery of rare-earth-free permanent magnets has been a goal of scientists for decades. The absence of rare-earth elements will alleviate a pressing concern about the availability of rare-earth elements used in permanent magnets. These magnets are crucial for applications such as wind turbines, electric cars, and memory devices. Rare-earth magnets are special owing to a large magnetic anisotropy energy (K 1 ). In contrast, iron cobalt phosphides hold promise since doping P into cubic FeCo can induce anisotropy, leading to a large coercivity, without introducing rare-earth elements. We present a comprehensive search over the Fe-Co-P ternary space for magnets, utilizing recently developed adaptive machine learning feedback to efficiently screen over 850 000 structures. We focus on machine learning acceleration as a paradigm for materials design. Further adaptive genetic algorithm searches and first-principles calculations aid in the identification of 16 new structures below the known convex hull. Five of them possess high magnetic polarization (J s > 1 T). The structures with desirable magnetic properties center on (Fe,Co) 2⁢ P. This supports conventional wisdom, which focuses on the mixture of the two known end compounds: Fe 2 ⁢P and Co 2 ⁢P. Our work provides guidance for synthesis. We find Fe 7 ⁢CoP 4 shows the most promise (J s = 1.03T and K 1 = 0.83MJ/m 3 ).

36 MATERIALS SCIENCE↗
DOE OSTI2021

Discrete theta angles, symmetries and anomalies

Gauge theories in various dimensions often admit discrete theta angles, that arise from gauging a global symmetry with an additional symmetry protected topological (SPT) phase. We discuss how the global symmetry and ’t Hooft anomaly depends on the discrete theta angles by coupling the gauge theory to a topological quantum field theory (TQFT). We observe that gauging an Abelian subgroup symmetry, that participates in symmetry extension, with an additional SPT phase leads to a new theory with an emergent Abelian symmetry that also participates in a symmetry extension. The symmetry extension of the gauge theory is controlled by the discrete theta angle which comes from the SPT phase. We find that discrete theta angles can lead to two-group symmetry in 4d 4 d QCD with SU(N),SU(N)/\mathbb{Z}_k S U ( N ) , S U ( N ) / ℤ k or SO(N) S O ( N ) gauge groups as well as various 3d 3 d and 2d 2 d gauge theories.

Hsin, Po-Shen↗
DOE OSTI2020

Materials Data on HoTaTiO6 by Materials Project

HoTiTaO6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.26–2.59 Å. Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.78–2.33 Å. Ta5+ is bonded to six O2- atoms to form distorted corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of Ta–O bond distances ranging from 1.87–2.22 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ti4+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ti4+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+, one Ti4+, and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+, one Ti4+, and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Trivalent f-Element Squarates, Squarate-Oxalates, and Cationic Materials, and the Determination of the Nine-Coordinate Ionic Radius of Cf(III)

The synthesis, structure, and solid-state UV–vis–NIR spectroscopy of four new f-element squarates, M 2 (C 4 O 4 ) 3 (H 2 O) 4 (M = Eu, Am, Cf) and Sm(C 4 O 4 )(C 4 O 3 OH)(H 2 O) 2 ·0.5H 2 O, four new cationic lanthanide squarate chlorides, [M 4 (C 4 O 4 ) 5 (H 2 O) 12 ]Cl 2 ·5H 2 O (M = Eu, Dy, Ho Er), and two new actinide squarate oxalates, M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 (M = Am, Cf), are presented. All of the metal centers are trivalent. Single-crystal X-ray diffraction analysis reveals that M 2 (C 4 O 4 ) 3 (H 2 O) 4 and Sm(C 4 O 4 )(C 4 O 3 OH)(H 2 O) 2 ·0.5H 2 O have a two-dimensional sheet structure constructed from MO 7 (H 2 O) 2 monocapped square-antiprismatic (coordination number (CN) = 9) metal centers and SmO 6 (H 2 O) 2 square-antiprismatic (CN = 8) metal centers, respectively, whereas M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 have a three-dimensional (3D) structure constructed from MO 7 (H 2 O) 2 monocapped square-antiprismatic (CN = 9) metal centers. Additionally, the cationic framework materials [M 4 (C 4 O 4 ) 5 (H 2 O) 12 ]Cl 2 ·5H 2 O have a 3D structure constructed from two crystallographically unique MO 5 (H 2 O) 3 square-antiprismatic (CN = 8) metal centers. In these structures, the squarate ligands bind to the metal centers with varying coordination modes and denticities. The results of this study provide another example of the nonparallel chemistry between the lanthanides and transplutonium elements. From the crystallographic data for the isotypic series M 2 (C 4 O 4 ) 3 (H 2 O) 4 (M = La–Nd, Sm, Eu) and the linear regression fit to a plot of the unit cell volume as a function of the cube of the ionic radius, the nine-coordinate ionic radius of Cf 3+ was determined to be 1.127 ± 0.003 Å. Lastly, computational analysis of the americium and californium complexes M 2 (C 4 O 4 ) 3 (H 2 O) 4 and M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 reveals three important attributes: (i) the 5f orbitals are nonbonding in all cases, with the bonding differences occurring with the empty 6d orbitals; (ii) the Cf complexes exhibit more covalent character than their Am counterparts; and (iii) there is more covalent character in the squarate-oxalate complexes than in the squarate complexes.

Crystallography↗
DOE OSTI2021

Geometry of the charge density wave in the kagome metal A V 3 Sb 5

Kagome lattice is a fertile platform for topological and intertwined electronic excitations. Recently, experimental evidence of an unconventional charge density wave (CDW) is observed in a Z 2 kagome metal AV 3 Sb 5 (A=K, Cs, Rb). This observation triggers wide interest in the interplay between frustrated crystal structure and Fermi surface instabilities. Here, we analyze the lattice effect and its impact on CDW in AV 3 Sb 5 . Based on published experimental data, we show that the 2×2×2 CDW breaks the sixfold rotational symmetry of the crystal due to the phase shift between kagome layers and can explain the twofold symmetric CDW peak intensity observed by scanning tunneling spectroscopy. The coupling between the lattice and electronic degrees of freedom yields a weak first-order structural transition without continuous change of lattice dynamics. Our result emphasizes the fundamental role of lattice geometry in proper understanding of unconventional electronic orders in AV 3 Sb 5 .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Pressure-Induced Spectroscopic Changes in a Californium 1D Material Are Twice as Large as Found in the Holmium Analog

Here, in this study, the synthesis, characterization, and pressure response of a 1D californium mellitate (mellitate = 1,2,3,4,5,6-benzenehexacarboxylate) coordination polymer, Cf 2 (mell)(H 2 O) 10 ·4H 2 O (Cf-1), are reported. The Cf–O lengths within the crystal structure are compared to its gadolinium (Gd-1) and holmium (Ho-1) analogs as well. These data show that the average Cf–O bond distance is slightly longer than the average Gd–O bond, consistent with trends in effective ionic radii. UV–vis-NIR absorption spectra as a function of pressure were collected using diamond-anvil techniques for both Cf-1 and Ho-1. These experiments show that the Cf(III) f → f transitions have a stronger dependence on pressure than that of the holmium analog. In the former case, the shift is nearly linear with applied pressure and averages 6.6 cm –1 /GPa, whereas in the latter, it is <3 cm –1 /GPa.

absorption spectroscopy↗
DOE OSTI2020

Materials Data on NaLiHo2F8 by Materials Project

NaLiHo2F8 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Na1+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of Na–F bond distances ranging from 2.21–2.55 Å. Li1+ is bonded to six F1- atoms to form distorted corner-sharing LiF6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (1.90 Å) and four longer (2.25 Å) Li–F bond lengths. Ho3+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Ho–F bond distances ranging from 2.20–2.45 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent Ho3+ atoms. In the second F1- site, F1- is bonded to one Na1+, one Li1+, and two equivalent Ho3+ atoms to form a mixture of distorted corner and edge-sharing FNaLiHo2 trigonal pyramids. In the third F1- site, F1- is bonded in a trigonal planar geometry to one Na1+ and two equivalent Ho3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent Ho3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2Sn3(PbS4)3 by Materials Project

Ho2Pb3Sn3S12 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to seven S2- atoms to form distorted HoS7 pentagonal bipyramids that share corners with two equivalent SnS6 octahedra, edges with four SnS6 octahedra, and edges with two equivalent HoS7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 49°. There are a spread of Ho–S bond distances ranging from 2.77–2.84 Å. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ho–S bond distances ranging from 2.82–3.08 Å. There are three inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Pb–S bond distances ranging from 2.97–3.29 Å. In the second Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.93–3.27 Å. In the third Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Pb–S bond distances ranging from 2.91–3.23 Å. There are three inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to six S2- atoms to form SnS6 octahedra that share corners with two equivalent HoS7 pentagonal bipyramids, edges with two equivalent SnS6 octahedra, and edges with two equivalent HoS7 pentagonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.54–2.63 Å. In the second Sn4+ site, Sn4+ is bonded to six S2- atoms to form SnS6 octahedra that share edges with two equivalent SnS6 octahedra and edges with two equivalent HoS7 pentagonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.54–2.65 Å. In the third Sn4+ site, Sn4+ is bonded to five S2- atoms to form corner-sharing SnS5 trigonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.45–2.58 Å. There are twelve inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to one Ho3+, one Pb2+, and two equivalent Sn4+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, two equivalent Pb2+, and one Sn4+ atom. In the third S2- site, S2- is bonded in a distorted single-bond geometry to four Pb2+ and one Sn4+ atom. In the fourth S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, two equivalent Pb2+, and one Sn4+ atom. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to one Ho3+, one Pb2+, and two equivalent Sn4+ atoms. In the sixth S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, two equivalent Pb2+, and one Sn4+ atom. In the seventh S2- site, S2- is bonded to one Ho3+, one Pb2+, and two equivalent Sn4+ atoms to form distorted corner-sharing SHoSn2Pb trigonal pyramids. In the eighth S2- site, S2- is bonded in a 5-coordinate geometry to four Pb2+ and one Sn4+ atom. In the ninth S2- site, S2- is bonded in a 2-coordinate geometry to one Ho3+, one Pb2+, and two equivalent Sn4+ atoms. In the tenth S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ho3+, two equivalent Pb2+, and one Sn4+ atom. In the eleventh S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, two equivalent Pb2+, and one Sn4+ atom. In the twelfth S2- site, S2- is bonded in a 4-coordinate geometry to one Ho3+, one Pb2+, and two equivalent Sn4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoTa3O9 by Materials Project

HoTa3O9 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.30–2.51 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 32–50°. There are a spread of Ta–O bond distances ranging from 1.96–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–50°. There are a spread of Ta–O bond distances ranging from 1.86–2.19 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoTa7O19 by Materials Project

HoTa7O19 crystallizes in the hexagonal P-6c2 space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are six shorter (2.40 Å) and two longer (2.63 Å) Ho–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ta–O bond distances ranging from 1.93–2.46 Å. In the second Ta5+ site, Ta5+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Ta–O bond lengths are 2.01 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and three equivalent Ta5+ atoms.

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