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At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on KHfMg6 by Materials Project

KMg6Hf crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. K is bonded to twelve Mg atoms to form KMg12 cuboctahedra that share corners with four equivalent KMg12 cuboctahedra, corners with eight equivalent HfMg12 cuboctahedra, edges with eight equivalent MgK2Hf2Mg8 cuboctahedra, faces with two equivalent KMg12 cuboctahedra, faces with four equivalent MgK2Hf2Mg8 cuboctahedra, and faces with four equivalent HfMg12 cuboctahedra. There are a spread of K–Mg bond distances ranging from 3.33–3.54 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to two equivalent K, eight Mg, and two equivalent Hf atoms to form distorted MgK2Hf2Mg8 cuboctahedra that share corners with twelve equivalent MgK2Hf2Mg8 cuboctahedra, edges with four equivalent KMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, faces with two equivalent KMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with six equivalent MgK2Hf2Mg8 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.28–3.37 Å. There are one shorter (3.31 Å) and one longer (3.35 Å) Mg–Hf bond lengths. In the second Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent K, six Mg, and two equivalent Hf atoms. There are one shorter (2.98 Å) and one longer (3.01 Å) Mg–Mg bond lengths. Both Mg–Hf bond lengths are 3.16 Å. In the third Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent K, six Mg, and two equivalent Hf atoms. Both Mg–Hf bond lengths are 3.13 Å. In the fourth Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent K, six Mg, and two equivalent Hf atoms. Both Mg–Hf bond lengths are 3.16 Å. Hf is bonded to twelve Mg atoms to form HfMg12 cuboctahedra that share corners with four equivalent HfMg12 cuboctahedra, corners with eight equivalent KMg12 cuboctahedra, edges with eight equivalent MgK2Hf2Mg8 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, faces with four equivalent KMg12 cuboctahedra, and faces with four equivalent MgK2Hf2Mg8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfMg6Ni by Materials Project

Mg6HfNi crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded to eight Mg, two equivalent Hf, and two equivalent Ni atoms to form distorted MgHf2Mg8Ni2 cuboctahedra that share corners with four equivalent HfMg10Ni2 cuboctahedra, corners with four equivalent NiHf2Mg10 cuboctahedra, corners with ten equivalent MgHf2Mg8Ni2 cuboctahedra, edges with two equivalent HfMg10Ni2 cuboctahedra, edges with two equivalent NiHf2Mg10 cuboctahedra, edges with six MgHf2Mg8Ni2 cuboctahedra, faces with two equivalent HfMg10Ni2 cuboctahedra, faces with two equivalent NiHf2Mg10 cuboctahedra, and faces with six MgHf2Mg8Ni2 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 2.92–3.07 Å. There are one shorter (3.08 Å) and one longer (3.15 Å) Mg–Hf bond lengths. There are one shorter (3.05 Å) and one longer (3.17 Å) Mg–Ni bond lengths. In the second Mg site, Mg is bonded in a 12-coordinate geometry to four Mg, two equivalent Hf, and two equivalent Ni atoms. There are one shorter (3.07 Å) and one longer (3.15 Å) Mg–Mg bond lengths. Both Mg–Hf bond lengths are 3.03 Å. Both Mg–Ni bond lengths are 2.96 Å. In the third Mg site, Mg is bonded in a 2-coordinate geometry to six Mg and two equivalent Ni atoms. Both Mg–Mg bond lengths are 2.97 Å. Both Mg–Ni bond lengths are 2.99 Å. In the fourth Mg site, Mg is bonded to ten Mg and two equivalent Hf atoms to form MgHf2Mg10 cuboctahedra that share corners with six equivalent MgHf2Mg10 cuboctahedra, edges with four equivalent HfMg10Ni2 cuboctahedra, edges with eight equivalent MgHf2Mg8Ni2 cuboctahedra, faces with two equivalent HfMg10Ni2 cuboctahedra, faces with six MgHf2Mg8Ni2 cuboctahedra, and faces with six equivalent NiHf2Mg10 cuboctahedra. Both Mg–Hf bond lengths are 3.00 Å. Hf is bonded to ten Mg and two equivalent Ni atoms to form distorted HfMg10Ni2 cuboctahedra that share corners with four equivalent NiHf2Mg10 cuboctahedra, corners with six equivalent HfMg10Ni2 cuboctahedra, corners with eight equivalent MgHf2Mg8Ni2 cuboctahedra, edges with two equivalent NiHf2Mg10 cuboctahedra, edges with eight MgHf2Mg8Ni2 cuboctahedra, faces with two equivalent HfMg10Ni2 cuboctahedra, faces with two equivalent NiHf2Mg10 cuboctahedra, and faces with six MgHf2Mg8Ni2 cuboctahedra. Both Hf–Ni bond lengths are 2.97 Å. Ni is bonded to ten Mg and two equivalent Hf atoms to form NiHf2Mg10 cuboctahedra that share corners with four equivalent HfMg10Ni2 cuboctahedra, corners with six equivalent NiHf2Mg10 cuboctahedra, corners with eight equivalent MgHf2Mg8Ni2 cuboctahedra, edges with two equivalent HfMg10Ni2 cuboctahedra, edges with four equivalent MgHf2Mg8Ni2 cuboctahedra, faces with two equivalent HfMg10Ni2 cuboctahedra, faces with two equivalent NiHf2Mg10 cuboctahedra, and faces with ten MgHf2Mg8Ni2 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Novel gas exposure system for the controlled exposure of plants to gaseous hydrogen fluoride

Abstract Plants can serve as sensitive bioindicators of the presence of contaminant vapors in the atmosphere. This work describes a novel laboratory-based gas exposure system capable of calibrating plants as bioindicators for the detection and delineation of the atmospheric contaminant hydrogen fluoride (HF) as a preparatory step for monitoring release emissions. To evaluate changes in plant phenotype and stress-induced physiological effects attributed to HF alone, the gas exposure chamber must have additional controls to simulate otherwise optimal plant growth conditions including variables such as light intensity, photoperiod, temperature, and irrigation. The exposure system was designed to maintain constant growth conditions during a series of independent experiments that varied between optimal (control) and stressful (HF exposure) conditions. The system was also designed to ensure the safe handling and application of HF. An initial system calibration introduced HF gas into the exposure chamber and monitored HF concentrations by cavity ring-down spectroscopy for a 48-h period. Stable concentrations inside the exposure chamber were observed after approximately 15 h, and losses of HF to the system ranged from 88 to 91%. A model plant species ( Festuca arundinacea ) was then exposed to HF for 48 h. Visual phenotype stress-induced responses aligned with symptoms reported in the literature for fluoride exposure (tip dieback and discoloration along the dieback transition margin). Fluoride concentrations in exposed tissues compared to control tissues confirmed enhanced fluoride uptake due to HF exposure. The system described herein can be applied to other reactive atmospheric pollutants of interest in support of bioindicator research.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2008

The Chronology of Asteroid Accretion, Differentiation, and Secondary Mineralization

We evaluate initial (Al-26/Al-27)(sub I), (Mn-53/Mn-55)(sub I), (Hf-182/Hf-180)(sub I), and Pb-207/Pb-206 ages for igneous differentiated meteorites and chondrules from ordinary chondrites for consistency with radioactive decay of the parent nuclides within a common, closed isotopic system, i.e., the early solar nebula. We find that the relative abundances of Al-26, Mn-53, and Hf-182, here denoted by I(Al)(sub CAI, I(Mn)(sub CAI) and I(Hf)(sub CAI), are consistent with decay from common initial values for the bulk solar system. I(Mn)(sub CAI) and I(Hf)(sub CAI) = 9.1+/-1.7 x 10(exp -6) and 1.06+/-0.09 x 10(exp -6) respectively, correspond to the canonical value of I(Al)(sub CAI) = 5.1 x 10(exp -5). I(Hf)(sub CAI) thus determined is consistent with I(Hf)(sub CAI) = 1.003+/-0.045 x 10(exp -6) directly determined in separate work. I(Mn)(sub CAI) is within error of the lowest value directly determined for CAI. We suggest that erratically higher values directly determined for CAI in carbonaceous chondrites reflect proton irradiation of unaccreted CAIs by the early Sun after other asteroids destined for melting by Al-26 decay had already accreted. The Mn-53 incorporated within such asteroids would have been shielded from further "local" spallogenic contributions. The relative abundances of the short-lived nuclides are less consistent with the Pb-207/Pb-206 ages of the corresponding materials with the best consistency being obtained between (Hf-182/Hf-180)(sub I) and Pb-207/Pb-206 ages of angrites. (Hf-182/Hf-180)(sub I) decreases with decreasing Pb-207/Pb-206 ages at the rate expected from the 8.90+/-0.09 Ma half-life of Hf-182. However, the model "CAI age" thus determined, T(sub CAI,Mn-W) = 4568.6+/-0.7 Ma, is older than the commonly accepted directly measured value T(sub CAI) = 4567.l+/-0.2 Ma. I(Al)(sub I), and (Mn-53/Mn-55)(sub I) are less consistent with Pb-207/Pb-206 ages, but determine T(sub CAI, Mn-Cr) = 4568.3+/-0.5 Ma relative to I(AI)(sub CAI)= 5.1 x 10(exp -5) and a Pb-207/Pb-206 age of 4558.6 Ma for the LEW86010 angrite. However. the (Mn-53/Mn-55)(sub I) and Pb-207/Pb-206 ages of "intermediate" age D'Orbigny-clan angrites and Asuka 881394 are inconsistent with radioactive decay from CAI values with a Mn-55 half-life of 3.7+/-0.4 Ma. in spite of consistency between (Mn-53/Mn-55)(sub I) and (Al-26/Al-27)(sub I). Nevertheless, it appears that the Mn-Cr method with I(Mn)(sub CAI) = 9.1+/-1.7 x 10(exp -6) can be used to date primary igneous events and also secondary mineralization on asteroid parent bodies. We summarize ages thus determined for igneous events on differentiated asteroids and for carbonate and fayalite formation on carbonaceous asteroids.

Nyquist, L. E.↗
DOE OSTI2020

Trace Chemical Detection Using Intercalated MXenes as a Signal Enhancing Substrate in Optical Probes

MXenes are 2D materials composed of layered transition metal nitrides or carbides. These materials are synthesized by HF exfoliation from MAX phases (Ti{sub 3}AlC{sub 2}). The 2D nanomaterial was synthesized by the removal of the 'A' element, resulting in a Mxene product (Ti{sub 3}C{sub 2}). MXenes have the general formula M{sub n+1}X{sub n}T{sub x}, where M is an early transition metal, X is Carbon and/or Nitrogen, and T accounts for surface terminated functional groups such as Fluoride, hydroxyl, and oxygen. These materials have very unique properties, similar to graphene, that allows them to be applied in a variety of trace detection techniques including surface-enhanced Raman spectroscopy (SERS). MXenes have also been demonstrated to selectively uptake uranyl ion, UO{sub 2}{sup 2+}. If this property can be combined with SERS or fluorescence detection, it may be possible to use MXenes as the basis for an alternative method to kinetic phosphorescence analysis (KPA) for trace uranyl measurements. Objectives: To confirm that MXene Nano materials are suitable substrates for SERS and sensor development by enhancing Raman signaling. To determine if certain MXene preparation methods yield materials that are more suitable for trace sensing methods. To determine uranyl uptake properties of these MXene materials and test them for analytical signals. Sample Preparation: Preparation of Ti{sub 3}C{sub 2}MXene (at FSU). MXenes were prepared by etching Al from Ti{sub 3}AlC{sub 2} (MAX phase)material. Two etching techniques yield different MXene products: LiF/HCl: Milder reaction, larger MXene flakes. HF: Harsher reaction, smaller flakes, larger layer separation. Products washed to remove etchant, vacuum filtered, and dried. Dried MXene flakes are air-stable. Film preparation for sensor testing (at SRNL): Suspend powder in diH{sub 2}O, purge with Ar, sonicate for 30 min. Centrifuge and collect supernate with suspended particles. Observed LiF-etched Mxene yielded a higher density of particles and darker collected solution. Drop-cast (4 ml) supernate onto slides and dried with Ar. For Rhodamine B (RhB) testing, drop-cast 4 ml drops onto Mxene spots and dried with Ar. Scanning Electron Microscopy conditions: 10 kV Beam energy, high vacuum; Working distance of 8 mm; beam penetration depth appx. 4 microns, beam spot size appx. 2 nanometers. Results: Detection of aluminum correlates with bright spots on image. Presence of aluminum shows that LiF/HCl etching was less thorough than HF etching. Trace Cl detection in LiF images suggests incomplete rinsing. HF has smaller feature size, more layer structure, and increased homogeneity, consistent with expectations. Macroscopic Raman spectroscopy measurements: 532 nm excitation, ∼50 mW with a ∼100 micron spot size (InPhotonics RPB probe). Kaiser Optical Holospec f/1.8 spectrometer with cooled (-60 deg.C) Andor iDus OE420 CCD. LiF 1x supernate showed good signal for trace measurements of Rhodamine B. HF and 1/4x LiF supernates showed little Mxene or Rhodamine B signal. Low deposition densities led to excess background signal from glass slides. For LiF film, response is linear with Rhodamine B concentration over range tested. Will retest with Raman microscope (∼1 micron spot size) to characterize SERS of more dilute LiF and HF etched Mxenes. Conclusions: The LiF etched material was more suitable for macroscopic SERS measurements because it was more concentrated, resulting in a thicker film than the HF etched Mxene and diluted LiF sample. However, the other materials may give greater SERS enhancements, which we hope to determine from measurements with the Raman microscope. From characterization with SEM we concluded that the HF etched Mxene is more uniform/homogenous and has smaller particle size than the LiF etched Mxene. There is still aluminum present in both samples indicating that etching wasn't complete, but the removal of the aluminum was more efficient in the HF method. Path Forward: Observe SERS with Raman microscopy, to obtain better signals for the more diluted samples and be able to compare enhancement effects for the different MXenes. Characterize uranyl sorption into MXene films and test Raman and fluorescence signals. Revisit the etching conditions to improve removal of aluminum. FSU and SRNL will continue to collaborate to create and characterize different Mxene materials and test their usefulness for sensor applications.

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

Materials Data on Hf5Te4 by Materials Project

Hf5Te4 is Titanium telluride structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to five equivalent Te atoms. There are four shorter (2.92 Å) and one longer (2.93 Å) Hf–Te bond lengths. In the second Hf site, Hf is bonded in a distorted square co-planar geometry to four equivalent Te atoms. All Hf–Te bond lengths are 3.13 Å. Te is bonded in a 6-coordinate geometry to six Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5Si3 by Materials Project

Hf5Si3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to five equivalent Si atoms. There are a spread of Hf–Si bond distances ranging from 2.71–2.96 Å. In the second Hf site, Hf is bonded in a 6-coordinate geometry to six equivalent Si atoms. All Hf–Si bond lengths are 2.80 Å. Si is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5Ge3 by Materials Project

Hf5Ge3 crystallizes in the hexagonal P6_3/mcm 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 Ge atoms. All Hf–Ge bond lengths are 2.84 Å. In the second Hf site, Hf is bonded in a 5-coordinate geometry to five equivalent Ge atoms. There are a spread of Hf–Ge bond distances ranging from 2.74–2.99 Å. Ge is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3Si2 by Materials Project

Hf3Si2 crystallizes in the tetragonal P4/mbm 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 Si atoms. There are two shorter (2.73 Å) and four longer (2.80 Å) Hf–Si bond lengths. In the second Hf site, Hf is bonded in a square co-planar geometry to four equivalent Si atoms. All Hf–Si bond lengths are 2.78 Å. Si is bonded in a 9-coordinate geometry to eight Hf and one Si atom. The Si–Si bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5Sn3 by Materials Project

Hf5Sn3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to five equivalent Sn atoms. There are a spread of Hf–Sn bond distances ranging from 2.91–3.13 Å. In the second Hf site, Hf is bonded in a 6-coordinate geometry to six equivalent Sn atoms. All Hf–Sn bond lengths are 2.97 Å. Sn is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5Ga3 by Materials Project

Hf5Ga3 crystallizes in the hexagonal P6_3/mcm 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 Ga atoms. All Hf–Ga bond lengths are 2.85 Å. In the second Hf site, Hf is bonded in a 5-coordinate geometry to five equivalent Ga atoms. There are a spread of Hf–Ga bond distances ranging from 2.74–3.09 Å. Ga is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2Fe by Materials Project

Hf2Fe 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 12-coordinate geometry to six equivalent Fe atoms. All Hf–Fe bond lengths are 2.65 Å. In the second Hf site, Hf is bonded in a 2-coordinate geometry to four equivalent Fe atoms. There are two shorter (2.73 Å) and two longer (3.06 Å) Hf–Fe bond lengths. Fe is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3Te2 by Materials Project

Hf3Te2 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two Hf3Te2 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 4-coordinate geometry to four equivalent Te atoms. All Hf–Te bond lengths are 2.95 Å. In the second Hf site, Hf is bonded in a distorted linear geometry to two equivalent Te atoms. Both Hf–Te bond lengths are 3.04 Å. Te is bonded in a 5-coordinate geometry to five Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3(Bi5Cl9)2 by Materials Project

Hf3BiCl18(Bi)9 crystallizes in the hexagonal P6_3 space group. The structure is zero-dimensional and consists of two Bi clusters and two Hf3BiCl18 clusters. In each Bi cluster, there are three inequivalent Bi sites. In the first Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. There are a spread of Bi–Bi bond distances ranging from 3.12–3.24 Å. In the second Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. There are one shorter (3.13 Å) and one longer (3.18 Å) Bi–Bi bond lengths. In the third Bi site, Bi is bonded in a 6-coordinate geometry to two equivalent Bi atoms. In each Hf3BiCl18 cluster, Hf is bonded in an octahedral geometry to six Cl atoms. There are a spread of Hf–Cl bond distances ranging from 2.38–2.56 Å. Bi is bonded in a trigonal planar geometry to three equivalent Cl atoms. All Bi–Cl bond lengths are 2.75 Å. There are six inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Hf atom. In the second Cl site, Cl is bonded in a single-bond geometry to one Hf atom. In the third Cl site, Cl is bonded in a bent 120 degrees geometry to one Hf and one Bi atom. In the fourth Cl site, Cl is bonded in a single-bond geometry to one Hf atom. In the fifth Cl site, Cl is bonded in a single-bond geometry to one Hf atom. In the sixth Cl site, Cl is bonded in a single-bond geometry to one Hf atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrHfO4 by Materials Project

PrHfO4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Pr4+ sites. In the first Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.34–2.69 Å. In the second Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.33–2.69 Å. In the third Pr4+ site, Pr4+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.33–2.72 Å. In the fourth Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.33–2.68 Å. In the fifth Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.33–2.70 Å. In the sixth Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.34–2.68 Å. In the seventh Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.34–2.69 Å. In the eighth Pr4+ site, Pr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.34–2.66 Å. There are eight inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.12–2.50 Å. In the second Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.11–2.57 Å. In the third Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.12–2.56 Å. In the fourth Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.10–2.53 Å. In the fifth Hf4+ site, Hf4+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.11–2.47 Å. In the sixth Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.11–2.55 Å. In the seventh Hf4+ site, Hf4+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.12–2.48 Å. In the eighth Hf4+ site, Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.10–2.52 Å. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the second O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with two OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the fourth O2- site, O2- is bonded to four Pr4+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to four Hf4+ atoms. In the sixth O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with two OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the ninth O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with two OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to four Hf4+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the thirteenth O2- site, O2- is bonded to four Pr4+ atoms to form OPr4 tetrahedra that share corners with nine OPr4 tetrahedra and edges with two OPr2Hf2 tetrahedra. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the fifteenth O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with four OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the seventeenth O2- site, O2- is bonded to four Pr4+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to four Hf4+ atoms. In the nineteenth O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with four OPr2Hf2 tetrahedra and edges with three OPr4 tetrahedra. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twenty-first O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with ten OPr2Hf2 tetrahedra and an edgeedge with one OPr4 tetrahedra. In the twenty-second O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with four OPr2Hf2 tetrahedra and edges with three OPr4 tetrahedra. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twenty-fifth O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with four OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the twenty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Hf4+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the twenty-ninth O2- site, O2- is bonded to four Pr4+ atoms to form OPr4 tetrahedra that share corners with nine OPr4 tetrahedra and edges with two OPr2Hf2 tetrahedra. In the thirtieth O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms. In the thirty-first O2- site, O2- is bonded to two Pr4+ and two Hf4+ atoms to form distorted OPr2Hf2 tetrahedra that share corners with two OPr4 tetrahedra and edges with three OPr2Hf2 tetrahedra. In the thirty-second O2- site, O2- is bonded in a 4-coordinate geometry to two Pr4+ and two Hf4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeHfO4 by Materials Project

CeHfO4 is alpha bismuth trifluoride-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.28–2.38 Å. In the second Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.28–2.36 Å. In the third Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.29–2.37 Å. In the fourth Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.27–2.38 Å. In the fifth Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.27–2.39 Å. In the sixth Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.28–2.37 Å. In the seventh Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.28–2.37 Å. In the eighth Ce4+ site, Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ce–O bond distances ranging from 2.29–2.38 Å. There are eight inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.21–2.33 Å. In the second Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.21–2.33 Å. In the third Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.13–2.50 Å. In the fourth Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.21–2.33 Å. In the fifth Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.21–2.33 Å. In the sixth Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.14–2.49 Å. In the seventh Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.21–2.34 Å. In the eighth Hf4+ site, Hf4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.20–2.34 Å. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the second O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the third O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 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. In the fifth O2- site, O2- is bonded to four Ce4+ atoms to form OCe4 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the sixth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the seventh O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the eighth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the ninth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the tenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the eleventh O2- site, O2- is bonded to four Hf4+ atoms to form a mixture of edge and corner-sharing OHf4 tetrahedra. In the twelfth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the thirteenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the fourteenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the fifteenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the sixteenth O2- site, O2- is bonded to four Ce4+ atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra. In the seventeenth O2- site, O2- is bonded to four Ce4+ atoms to form a mixture of edge and corner-sharing OCe4 tetrahedra. In the eighteenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the nineteenth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the twentieth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the twenty-first O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the twenty-second O2- site, O2- is bonded to four Hf4+ atoms to form a mixture of edge and corner-sharing OHf4 tetrahedra. In the twenty-third O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the twenty-fourth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the twenty-fifth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe2Hf2 tetrahedra and edges with six OCe4 tetrahedra. In the twenty-sixth O2- site, O2- is bonded to four Ce4+ atoms to form OCe4 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the twenty-seventh O2- site, O2- is bonded to four Hf4+ atoms to form a mixture of distorted edge and corner-sharing OHf4 tetrahedra. In the twenty-eighth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the twenty-ninth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the thirtieth O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form a mixture of edge and corner-sharing OCe2Hf2 tetrahedra. In the thirty-first O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra. In the thirty-second O2- site, O2- is bonded to two Ce4+ and two Hf4+ atoms to form OCe2Hf2 tetrahedra that share corners with sixteen OCe4 tetrahedra and edges with six OCe2Hf2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3Ge2 by Materials Project

Hf3Ge2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a square co-planar geometry to four equivalent Ge atoms. All Hf–Ge bond lengths are 2.81 Å. In the second Hf site, Hf is bonded in a 6-coordinate geometry to six equivalent Ge atoms. There are two shorter (2.74 Å) and four longer (2.86 Å) Hf–Ge bond lengths. Ge is bonded in a 9-coordinate geometry to eight Hf and one Ge atom. The Ge–Ge bond length is 2.65 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfZn16 by Materials Project

HfZn16 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Hf is bonded in a 9-coordinate geometry to fifteen Zn atoms. There are a spread of Hf–Zn bond distances ranging from 2.83–3.01 Å. There are seven inequivalent Zn sites. In the first Zn site, Zn is bonded in a 1-coordinate geometry to one Hf and ten Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.74–3.13 Å. In the second Zn site, Zn is bonded to two equivalent Hf and ten Zn atoms to form ZnHf2Zn10 cuboctahedra that share corners with two equivalent ZnHf2Zn10 cuboctahedra and faces with six equivalent ZnZn12 cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.64–2.87 Å. In the third Zn site, Zn is bonded in a 9-coordinate geometry to one Hf and twelve Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.54–3.12 Å. In the fourth Zn site, Zn is bonded in a 12-coordinate geometry to one Hf and eleven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.62–3.14 Å. In the fifth Zn site, Zn is bonded in a 11-coordinate geometry to one Hf and ten Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.53–2.90 Å. In the sixth Zn site, Zn is bonded in a 12-coordinate geometry to one Hf and eleven Zn atoms. There are one shorter (2.62 Å) and one longer (2.66 Å) Zn–Zn bond lengths. In the seventh Zn site, Zn is bonded to twelve Zn atoms to form distorted ZnZn12 cuboctahedra that share edges with three equivalent ZnZn12 cuboctahedra and faces with four ZnHf2Zn10 cuboctahedra. The Zn–Zn bond length is 2.89 Å.

36 MATERIALS SCIENCE↗