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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Hf4Ti(PbO3)5 by Materials Project

Hf4Ti(PbO3)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share a cornercorner with one TiO6 octahedra and corners with five HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Hf–O bond distances ranging from 2.04–2.16 Å. In the second Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent TiO6 octahedra and corners with four HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Hf–O bond distances ranging from 2.03–2.22 Å. In the third Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent TiO6 octahedra and corners with four HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Hf–O bond distances ranging from 2.02–2.22 Å. In the fourth Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share a cornercorner with one TiO6 octahedra and corners with five HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–16°. There are a spread of Hf–O bond distances ranging from 2.03–2.22 Å. In the fifth Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent TiO6 octahedra and corners with four HfO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Hf–O bond distances ranging from 2.03–2.22 Å. In the sixth Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share a cornercorner with one TiO6 octahedra and corners with five HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Hf–O bond distances ranging from 2.03–2.22 Å. In the seventh Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share a cornercorner with one TiO6 octahedra and corners with five HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–16°. There are a spread of Hf–O bond distances ranging from 2.04–2.15 Å. In the eighth Hf4+ site, Hf4+ is bonded to six O2- atoms to form HfO6 octahedra that share corners with two equivalent TiO6 octahedra and corners with four HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Hf–O bond distances ranging from 2.03–2.22 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Ti–O bond distances ranging from 1.91–2.14 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six HfO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Ti–O bond distances ranging from 1.91–2.14 Å. There are ten inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.53–2.83 Å. In the second Pb2+ site, Pb2+ is bonded in a 9-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.48–2.80 Å. In the third Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.52–2.80 Å. In the fourth Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.54–2.82 Å. In the fifth Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.52–2.84 Å. In the sixth Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.54–2.82 Å. In the seventh Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.52–2.82 Å. In the eighth Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.53–2.80 Å. In the ninth Pb2+ site, Pb2+ is bonded in a 9-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.48–2.80 Å. In the tenth Pb2+ site, Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.53–2.80 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twentieth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-first O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-second O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the twenty-third O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the twenty-ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Hf4+ and two Pb2+ atoms. In the thirtieth O2- site, O2- is bonded in a 2-coordinate geometry to one Hf4+, one Ti4+, and two Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfZrCoSb2Rh by Materials Project

HfZrRhCoSb2 is half-Heusler-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Hf is bonded in a body-centered cubic geometry to three equivalent Rh, one Co, and four Sb atoms. All Hf–Rh bond lengths are 2.80 Å. The Hf–Co bond length is 2.79 Å. There are three shorter (2.80 Å) and one longer (2.82 Å) Hf–Sb bond lengths. Zr is bonded in a body-centered cubic geometry to one Rh, three equivalent Co, and four Sb atoms. The Zr–Rh bond length is 2.83 Å. All Zr–Co bond lengths are 2.80 Å. There are one shorter (2.80 Å) and three longer (2.81 Å) Zr–Sb bond lengths. Rh is bonded to three equivalent Hf and one Zr atom to form distorted RhHf3Zr tetrahedra that share corners with four equivalent SbHf3Zr tetrahedra, corners with six equivalent RhHf3Zr tetrahedra, corners with six equivalent CoHfZr3 tetrahedra, and edges with six SbHf3Zr tetrahedra. Co is bonded to one Hf and three equivalent Zr atoms to form distorted CoHfZr3 tetrahedra that share corners with four equivalent SbHfZr3 tetrahedra, corners with six equivalent RhHf3Zr tetrahedra, corners with six equivalent CoHfZr3 tetrahedra, and edges with six SbHf3Zr tetrahedra. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to three equivalent Hf and one Zr atom to form distorted SbHf3Zr tetrahedra that share corners with four equivalent RhHf3Zr tetrahedra, corners with twelve SbHf3Zr tetrahedra, edges with three equivalent RhHf3Zr tetrahedra, and edges with three equivalent CoHfZr3 tetrahedra. In the second Sb site, Sb is bonded to one Hf and three equivalent Zr atoms to form distorted SbHfZr3 tetrahedra that share corners with four equivalent CoHfZr3 tetrahedra, corners with twelve SbHf3Zr tetrahedra, edges with three equivalent RhHf3Zr tetrahedra, and edges with three equivalent CoHfZr3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2Rh by Materials Project

Hf2Rh crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 6-coordinate geometry to six equivalent Rh atoms. All Hf–Rh bond lengths are 2.78 Å. In the second Hf site, Hf is bonded in a 2-coordinate geometry to four equivalent Rh atoms. There are two shorter (2.71 Å) and two longer (3.17 Å) Hf–Rh bond lengths. Rh is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Terminal and Super‐Basic Parent Imides of Hafnium

Abstract A dinuclear hafnium complex containing the parent imido ligand [(PN)(PNC)Hf=NH{μ 2 ‐K}] 2 ( 2 ) (PN − =(N‐(2‐P i Pr 2 ‐4‐methylphenyl)‐2,4,6‐Me 3 C 6 H 2 ; PNC 2− =(N‐(2‐P i Pr 2 ‐4‐methylphenyl)‐2,4,6‐CH 2 Me 2 C 6 H 2 ), was prepared by reduction of the bisazide trans‐[(PN) 2 Hf(N 3 ) 2 ] ( 1 ) with two equiv of KC 8 . Encapsulation of K + in 2 with crown‐ether or cryptand affords the first discrete salt [K(encap)][(PN)(PNC)Hf≡NH] (encap=18‐crown‐6(THF) 2 , 3 ; 2,2,2‐Kryptofix, 4 ), featuring a terminal parent imide and possessing some of the shortest Hf−N bond lengths known to date. DFT calculations revealed formation of 2 to proceed via an extremely basic monomeric nitrido, [(PN) 2 Hf≡N] − ( A ), having a computed p K BH+ of ∼57 followed by heterolytic splitting of an inert 1,2‐CH bond of a benzylic methyl group across the Hf≡N triple bond in A . An electronic structure analysis reveals A to possess a covalent Hf≡N triple bond and of super‐basic character. We also showcase reactivity of the Hf≡NH bond with various electrophiles.

Chemistry↗
DOE OSTI2023

Statistical chronometry of Meteorites: II. Initial abundances and homogeneity of short-lived radionuclides

Astrophysical models of planet formation require accurate radiometric dating of meteoritic components by short-lived (Al-Mg, Mn-Cr, Hf-W) and long-lived (U-Pb) chronometers, to develop a timeline of such events in the solar nebula as formation of Ca-rich, Al-rich Inclusions (CAIs), chondrules, planetesimals, etc. CAIs formed mostly around a time (“t=0”) when the short-lived radionuclide 26 Al (t 1/2 = 0.72 Myr) was present and presumably homogeneously distributed at a known level we define as ( 26 Al/ 27 Al) SS = 5.23 × 10 -5 . The time of formation after t=0 of another object can be found by determining its initial ( 26 Al/ 27 Al) 0 ratio and comparing it to ( 26 Al/ 27 Al) SS . Dating of meteoritic objects using the Mn-Cr or Hf-W systems is hindered because the abundances ( 53 Mn/ 55 Mn) SS and ( 182 Hf/ 180 Hf) SS at t=0 are not known precisely. To constrain these quantities, we compile literature Al-Mg, Mn-Cr, Hf-W and Pb-Pb data for 13 achondrites and use novel statistical techniques to minimize the discrepancies between their times of formation across these systems. We find that for ( 53 Mn/ 55 Mn) SS = (7.80±0.36)×10 -6 , ( 182 Hf/ 180 Hf) SS = (10.41 ± 0.12) × 10-5, t SS = 4568.65 ± 0.10 Myr, and a 53 Mn half-life of 3.98 ± 0.22 Myr, these four free parameters make concordant 18 formation times recorded by the different systems in all six known volcanic achondrites (the quenched angrites D’Orbigny, Sahara 99555, Northwest Africa 1670; the psuedo-eucrites Asuka 881394 and Ibitira; and the basaltic achondrite Northwest Africa 7325). These parameters also make concordant the ages derived for chondrules from CB/CH achondrites, formed simultaneously in an impact. The other seven achondrites are not quite concordant, but are plutonic angrites or ‘carbonaceous achondrites’ for which simultaneous closure of the isotopic systems might not be expected. Our findings provide very strong support for homogeneity of 26 Al, 53 Mn, and 182 Hf in the solar nebula, and our approach offers a path for more precise chronometry

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Planar multifrequency mid-IR microwave-pumped lasers

The characteristics of planar repetitively pulsed diffusion-cooled HF, DF, HF – DF, Xe, and HF – DF – Xe(Kr) lasers pumped by a microwave discharge (2.45 GHz) are studied depending on the pump pulse duration (10 – 40 μs) and repletion rate (50 – 400 Hz), as well as on the composition and pressure of the working gas mixture (30 – 200 Torr) at low (to 0.6 L s{sup −1}) gas flow rates. It is demonstrated for the first time that a HF – DF – Xe gas-discharge laser may simultaneously operate as a HF – DF chemical molecular laser and a recombination laser based on xenon atom transitions and generate broadband (octave) radiation in the range 2.0 – 4.2 μm with an average output power of 43 mW and an efficiency of 0.9 %. With substitution of xenon for krypton, lasing in a HF – DF – Kr laser is obtained at wavelengths of 2.52 – 4.15 μm. Lasing in a HF – DF laser was achieved simultaneously in two spectral regions (2.7 – 2.9 and 3.6 – 4.2 μm) with an output power of ∼50 mW. It is found that a decrease in the pump pulse duration with a simultaneous increase in the pulse repletion rate for retaining the average energy deposition leads to an increase in the average output power and efficiency of the laser. At low pulse repetition rates (50 – 100 Hz) and a low gas mixture flow rate, helium buffer gas can be effectively substituted for neon. Operation of the Xe laser was achieved in the spectral range 2.03 – 3.65 μm with an average output power of 580 Mw at a pump pulse duration of 20 μs, a pulse repetition rate to 10 kHz, and a maximum efficiency of 55 %. The obtained experimental results demonstrate the possibility of creating broadband HF – DF – Xe lasers emitting in the frequency range 2 – 4 μm with a desired ratio of intensities in different spectral ranges. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1996

Diminished forearm vasomotor response to central hypervolemic loading in aerobically fit individuals

The aim of this study was to test the hypothesis that cardiopulmonary baroreflex control of forearm vascular resistance (FVR) during central hypervolemic loading was less sensitive in exercise trained high fit individuals (HF) compared to untrained average fit individuals (AF). Eight AF (age: 24 +/- 1 yr and weight: 78.9 +/- 1.7 kg) and eight HF (22 +/- 1 yr 79.5 +/- 2.4 kg) voluntarily participated in the investigation. Maximal aerobic power (determined on a treadmill), plasma volume and blood volume (Evans blue dilution method) were significantly greater in the HF than AF (60.8 +/- 0.7 vs. 41.2 +/- 1.9 ml.kg-1.min-1, 3.96 +/- 0.17 vs 3.36 +/- 0.08 1, and 6.33 +/- 0.23 vs 5.28 +/- 0.13 1). Baseline heart rate (HR), central venous pressure (CVP), mean arterial pressure (MAP, measured by an intraradial catheter or a Finapres finger cuff), forearm blood flow (FBF, plethysmography), and FVR, calculated from the ratio (MAP-CVP)/FBF, were not different between the HF and the AF. Lower body negative pressure (LBNP, -5, -10, -15, and -20 torr) and passive leg elevation (LE, 50 cm) combined with lower body positive pressure (LBPP, +5, +10, and +20 torr) were utilized to elicit central hypovolemia and hypervolemia, respectively. Range of CVP (from LBNP to LE+LBPP) was similar in the AF (from -3.9 to +1.9 mm Hg) and HF (from -4.0 to +2.2 mm Hg). However, FVR/CVP was significantly less in the HF (-1.8 +/- 0.1 unit.mm Hg-1) than AF (-34 +/- 0.1 unit.mm Hg-1). The FVR decrease in response to increase in CVP was significantly diminished in the HF (-1.46 +/- 0.45 unit.mm Hg-1) compared to the AF (-4.40 +/- 0.97 unit.mm Hg-1), and during LBNP induced unloading the FVR/CVP of the HF (-2.01 +/- 0.49 unit.mm Hg-1) was less (P < 0.08) than the AF (-3.28 +/- 0.69 unit.mm Hg-1). We concluded that the cardiopulmonary baroreceptor mediated FVR reflex response was significantly less sensitive to changes in CVP in individuals who practice exercise training.

NASA Discipline Number 93-10↗
NASA NTRS2006

High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

Background: Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). Methods and Results: 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P<0.001). Conclusions: Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

Rahman, Atiar↗
NASA NTRS2004

High frequency QRS ECG predicts ischemic defects during myocardial perfusion imaging

Changes in high frequency QRS components of the electrocardiogram (HF QRS ECG) (150-250 Hz) are more sensitive than changes in conventional ST segments for detecting myocardial ischemia. We investigated the accuracy of 12-lead HF QRS ECG in detecting ischemia during adenosine tetrofosmin myocardial perfusion imaging (MPI). 12-lead HF QRS ECG recordings were obtained from 45 patients before and during adenosine technetium-99 tetrofosmin MPI tests. Before the adenosine infusions, recordings of HF QRS were analyzed according to a morphological score that incorporated the number, type and location of reduced amplitude zones (RAZs) present in the 12 leads. During the adenosine infusions, recordings of HF QRS were analyzed according to the maximum percentage changes (in both the positive and negative directions) that occurred in root mean square (RMS) voltage amplitudes within the 12 leads. The best set of prospective HF QRS criteria had a sensitivity of 94% and a specificity of 83% for correctly identifying the MPI result. The sensitivity of simultaneous ST segment changes (18%) was significantly lower than that of any individual HF QRS criterion (P less than 0.00l). Analysis of 12-lead HF QRS ECG is highly sensitive and specific for detecting ischemic perfusion defects during adenosine MPI stress tests and significantly more sensitive than analysis of conventional ST segments.

Source record↗
DOE OSTI2025

High performance porous Si anode enabled by an organic-solvent assisted etching process

Silicon (Si) is a promising anode for the next generation of lithium-ion batteries, but its large volume changes (~300 %) during cycling hindered its practical applications. One method to improve its stability is to etch micron sized Si/SiO 2 particles to form porous Si (p-Si) and accommodate volume changes internally. However, the conventional HF etching method generates excess gas/heat and is difficult to scale up. Herein, we developed an organic-solvent-assisted HF etching process (O-HF) using a mixture of benzene and saturated HF aqueous solution. The organic solvent can be preferentially absorbed on the surface of Si/SiO 2 powder so etching rate of SiO 2 can be controlled to avoid rapid gas/heat generation. This method can also prevent over-etching of Si by minimizing direct contact/react between water and newly exposed Si. Si||NMC622 cells using carbon coated p-Si particles prepared by optimized O-HF etching process demonstrate a capacity retention of 82.0 % after 500 cycles, which is much better than those prepared by conventional HF etching (73.7 %). The thickness of Si anode increases only ~10 % during the initial lithiation, which is comparable with those of graphite anode. In conclusion, the O-HF etching strategy developed in this work can also be applied to the etching of a broad range of materials.

HF etching↗
DOE OSTI2020

Materials Data on HfAl2 by Materials Project

HfAl2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Hf is bonded in a 12-coordinate geometry to four equivalent Hf and twelve Al atoms. There are three shorter (3.23 Å) and one longer (3.25 Å) Hf–Hf bond lengths. There are a spread of Hf–Al bond distances ranging from 3.08–3.11 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six equivalent Hf and six equivalent Al atoms to form a mixture of edge, face, and corner-sharing AlHf6Al6 cuboctahedra. All Al–Al bond lengths are 2.68 Å. In the second Al site, Al is bonded to six equivalent Hf and six Al atoms to form a mixture of edge, face, and corner-sharing AlHf6Al6 cuboctahedra. There are two shorter (2.56 Å) and two longer (2.69 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfCr2 by Materials Project

HfCr2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Hf is bonded in a 12-coordinate geometry to four equivalent Hf and twelve Cr atoms. All Hf–Hf bond lengths are 3.07 Å. There are three shorter (2.89 Å) and nine longer (2.95 Å) Hf–Cr bond lengths. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded to six equivalent Hf and six equivalent Cr atoms to form a mixture of edge, face, and corner-sharing CrHf6Cr6 cuboctahedra. All Cr–Cr bond lengths are 2.50 Å. In the second Cr site, Cr is bonded to six equivalent Hf and six Cr atoms to form a mixture of edge, face, and corner-sharing CrHf6Cr6 cuboctahedra. There are two shorter (2.49 Å) and two longer (2.55 Å) Cr–Cr bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfMn2 by Materials Project

HfMn2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Hf is bonded in a 12-coordinate geometry to four equivalent Hf and twelve Mn atoms. There are three shorter (3.01 Å) and one longer (3.04 Å) Hf–Hf bond lengths. There are a spread of Hf–Mn bond distances ranging from 2.87–2.91 Å. There are two inequivalent Mn sites. In the first Mn site, Mn is bonded to six equivalent Hf and six equivalent Mn atoms to form a mixture of corner, edge, and face-sharing MnHf6Mn6 cuboctahedra. All Mn–Mn bond lengths are 2.50 Å. In the second Mn site, Mn is bonded to six equivalent Hf and six Mn atoms to form a mixture of corner, edge, and face-sharing MnHf6Mn6 cuboctahedra. There are two shorter (2.39 Å) and two longer (2.51 Å) Mn–Mn bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2In5 by Materials Project

Hf2In5 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Hf is bonded to two equivalent Hf and ten In atoms to form a mixture of distorted edge, face, and corner-sharing HfHf2In10 cuboctahedra. Both Hf–Hf bond lengths are 3.08 Å. There are a spread of Hf–In bond distances ranging from 3.06–3.17 Å. There are two inequivalent In sites. In the first In site, In is bonded in a 10-coordinate geometry to four equivalent Hf and six In atoms. There are two shorter (3.08 Å) and four longer (3.10 Å) In–In bond lengths. In the second In site, In is bonded in a 10-coordinate geometry to four equivalent Hf and six In atoms. There are a spread of In–In bond distances ranging from 3.08–3.39 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Hf7O16 by Materials Project

Ca2Hf7O16 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.46–2.58 Å. In the second Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.46–2.58 Å. In the third Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.46–2.58 Å. In the fourth Ca2+ site, Ca2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.46–2.58 Å. There are seven inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to seven O2- atoms to form distorted HfO7 pentagonal bipyramids that share a cornercorner with one HfO6 octahedra, corners with two equivalent HfO7 pentagonal bipyramids, and edges with seven HfO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of Hf–O bond distances ranging from 2.03–2.28 Å. In the second Hf4+ site, Hf4+ is bonded to seven O2- atoms to form distorted HfO7 pentagonal bipyramids that share a cornercorner with one HfO6 octahedra, corners with two equivalent HfO7 pentagonal bipyramids, and edges with seven HfO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of Hf–O bond distances ranging from 2.03–2.28 Å. In the third Hf4+ site, Hf4+ is bonded to six equivalent O2- atoms to form corner-sharing HfO6 octahedra. All Hf–O bond lengths are 2.10 Å. In the fourth Hf4+ site, Hf4+ is bonded to seven O2- atoms to form distorted HfO7 pentagonal bipyramids that share a cornercorner with one HfO6 octahedra, corners with two equivalent HfO7 pentagonal bipyramids, and edges with seven HfO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of Hf–O bond distances ranging from 2.03–2.28 Å. In the fifth Hf4+ site, Hf4+ is bonded to six equivalent O2- atoms to form corner-sharing HfO6 octahedra. All Hf–O bond lengths are 2.10 Å. In the sixth Hf4+ site, Hf4+ is bonded to seven O2- atoms to form distorted HfO7 pentagonal bipyramids that share a cornercorner with one HfO6 octahedra, corners with two equivalent HfO7 pentagonal bipyramids, and edges with seven HfO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of Hf–O bond distances ranging from 2.03–2.28 Å. In the seventh Hf4+ site, Hf4+ is bonded to six equivalent O2- atoms to form corner-sharing HfO6 octahedra. All Hf–O bond lengths are 2.10 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two Hf4+ atoms. In the second O2- site, O2- is bonded to one Ca2+ and three equivalent Hf4+ atoms to form a mixture of distorted edge and corner-sharing OCaHf3 tetrahedra. In the third O2- site, O2- is bonded to one Ca2+ and three equivalent Hf4+ atoms to form a mixture of edge and corner-sharing OCaHf3 tetrahedra. In the fourth O2- site, O2- is bonded to four Hf4+ atoms to form a mixture of distorted edge and corner-sharing OHf4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YHfMg14O16 by Materials Project

Mg14YHfO16 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are five inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, corners with two equivalent HfO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.08–2.19 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.09–2.31 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent HfO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.16–2.24 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent HfO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.16–2.24 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one YO6 octahedra, an edgeedge with one HfO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Mg–O bond distances ranging from 2.15–2.25 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.19 Å) and four longer (2.27 Å) Y–O bond lengths. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.19 Å) and four longer (2.31 Å) Hf–O bond lengths. There are ten inequivalent O sites. In the first O site, O is bonded to five Mg and one Y atom to form a mixture of corner and edge-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O site, O is bonded to five Mg and one Hf atom to form a mixture of corner and edge-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. Both O–Mg bond lengths are 2.19 Å. In the third O site, O is bonded to five Mg and one Hf atom to form a mixture of corner and edge-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are two shorter (2.15 Å) and two longer (2.19 Å) O–Mg bond lengths. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. In the fifth O site, O is bonded to four equivalent Mg and two equivalent Y atoms to form OY2Mg4 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to four Mg and two equivalent Hf atoms to form OHf2Mg4 octahedra that share corners with six OMg6 octahedra and edges with twelve OHfMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to five Mg and one Y atom to form a mixture of corner and edge-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are two shorter (2.19 Å) and two longer (2.25 Å) O–Mg bond lengths. In the ninth O site, O is bonded to five Mg and one Hf atom to form a mixture of corner and edge-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. The O–Mg bond length is 2.08 Å. In the tenth O site, O is bonded to five Mg and one Hf atom to form a mixture of corner and edge-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are one shorter (2.08 Å) and two longer (2.15 Å) O–Mg bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf6Be15Ni8 by Materials Project

Be15Hf6Ni8 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are three inequivalent Be sites. In the first Be site, Be is bonded to four equivalent Be, four equivalent Hf, and four equivalent Ni atoms to form a mixture of distorted face and corner-sharing BeHf4Be4Ni4 cuboctahedra. All Be–Be bond lengths are 2.24 Å. All Be–Hf bond lengths are 2.77 Å. All Be–Ni bond lengths are 2.38 Å. In the second Be site, Be is bonded in a body-centered cubic geometry to eight equivalent Ni atoms. All Be–Ni bond lengths are 2.35 Å. In the third Be site, Be is bonded in a 12-coordinate geometry to six Be, three equivalent Hf, and three equivalent Ni atoms. All Be–Be bond lengths are 2.27 Å. All Be–Hf bond lengths are 2.76 Å. All Be–Ni bond lengths are 2.33 Å. Hf is bonded in a 12-coordinate geometry to eight Be and four equivalent Ni atoms. All Hf–Ni bond lengths are 2.65 Å. Ni is bonded in a 10-coordinate geometry to seven Be and three equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfZr(SbRh)2 by Materials Project

HfZr(RhSb)2 is half-Heusler-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Hf is bonded in a body-centered cubic geometry to four Rh and four Sb atoms. There are one shorter (2.74 Å) and three longer (2.82 Å) Hf–Rh bond lengths. There are one shorter (2.80 Å) and three longer (2.81 Å) Hf–Sb bond lengths. Zr is bonded in a body-centered cubic geometry to four Rh and four Sb atoms. There are one shorter (2.82 Å) and three longer (2.84 Å) Zr–Rh bond lengths. There are three shorter (2.83 Å) and one longer (2.85 Å) Zr–Sb bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded to one Hf and three equivalent Zr atoms to form distorted RhHfZr3 tetrahedra that share corners with four equivalent SbHfZr3 tetrahedra, corners with twelve RhHfZr3 tetrahedra, and edges with six SbHf3Zr tetrahedra. In the second Rh site, Rh is bonded to three equivalent Hf and one Zr atom to form distorted RhHf3Zr tetrahedra that share corners with four equivalent SbHf3Zr tetrahedra, corners with twelve RhHfZr3 tetrahedra, and edges with six SbHf3Zr tetrahedra. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to three equivalent Hf and one Zr atom to form distorted SbHf3Zr tetrahedra that share corners with four equivalent RhHf3Zr tetrahedra, corners with twelve SbHf3Zr tetrahedra, and edges with six RhHfZr3 tetrahedra. In the second Sb site, Sb is bonded to one Hf and three equivalent Zr atoms to form distorted SbHfZr3 tetrahedra that share corners with four equivalent RhHfZr3 tetrahedra, corners with twelve SbHf3Zr tetrahedra, and edges with six RhHfZr3 tetrahedra.

36 MATERIALS SCIENCE↗