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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na2Th(SO6)3 by Materials Project

Na2ThS3O16O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four hydrogen peroxide molecules and one Na2ThS3O16 framework. In the Na2ThS3O16 framework, there are two inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.25–2.97 Å. In the second Na site, Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with four SO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.36–2.65 Å. Th is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Th–O bond distances ranging from 2.31–2.42 Å. There are three inequivalent S sites. In the first S site, S is bonded to four O atoms to form SO4 tetrahedra that share a cornercorner with one NaO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of S–O bond distances ranging from 1.45–1.55 Å. In the second S site, S is bonded to four O atoms to form SO4 tetrahedra that share a cornercorner with one NaO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of S–O bond distances ranging from 1.45–1.53 Å. In the third S site, S is bonded to four O atoms to form SO4 tetrahedra that share corners with two equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of S–O bond distances ranging from 1.44–1.54 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Th and one S atom. In the second O site, O is bonded in a bent 120 degrees geometry to two Na atoms. In the third O site, O is bonded in a distorted bent 120 degrees geometry to one Na and one S atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Na and one S atom. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Na and one S atom. In the sixth O site, O is bonded in a 2-coordinate geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the seventh O site, O is bonded in a distorted bent 150 degrees geometry to one Th and one S atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to one Na and one Th atom. In the ninth O site, O is bonded in a bent 150 degrees geometry to one Th and one S atom. In the tenth O site, O is bonded in a bent 150 degrees geometry to one Na and one S atom. In the eleventh O site, O is bonded in a linear geometry to one Th and one S atom. In the twelfth O site, O is bonded in a distorted bent 120 degrees geometry to one Na and one S atom. In the thirteenth O site, O is bonded in a bent 150 degrees geometry to one Na and one O atom. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to one Th and one S atom. In the fifteenth O site, O is bonded in a bent 150 degrees geometry to one Th and one S atom. In the sixteenth O site, O is bonded in a distorted single-bond geometry to two Na and one S atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th5Pb4 by Materials Project

Th5Pb4 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Th sites. In the first Th site, Th is bonded in a 6-coordinate geometry to six equivalent Pb atoms. All Th–Pb bond lengths are 3.50 Å. In the second Th site, Th is bonded to seven Pb atoms to form a mixture of distorted corner, edge, and face-sharing ThPb7 pentagonal bipyramids. There are a spread of Th–Pb bond distances ranging from 3.25–3.45 Å. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded to six equivalent Th atoms to form distorted face-sharing PbTh6 octahedra. In the second Pb site, Pb is bonded in a 9-coordinate geometry to nine Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2Fe17C by Materials Project

Th2Fe17C crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Th is bonded in a distorted single-bond geometry to fourteen Fe and one C atom. There are a spread of Th–Fe bond distances ranging from 3.05–3.34 Å. The Th–C bond length is 2.62 Å. There are seven inequivalent Fe sites. In the first Fe site, Fe is bonded to three equivalent Th and nine Fe atoms to form distorted FeTh3Fe9 cuboctahedra that share corners with seventeen FeTh3Fe9 cuboctahedra, corners with two equivalent CTh2Fe4 octahedra, edges with seven FeTh3Fe9 cuboctahedra, faces with fourteen FeTh3Fe9 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.71 Å. In the second Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.48–2.69 Å. The Fe–C bond length is 1.92 Å. In the third Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form FeTh2Fe10 cuboctahedra that share corners with twelve FeTh3Fe9 cuboctahedra, corners with two equivalent CTh2Fe4 octahedra, edges with eight FeTh2Fe10 cuboctahedra, and faces with twelve FeTh3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. There are four shorter (2.43 Å) and two longer (2.66 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with eighteen FeTh3Fe9 cuboctahedra, edges with six FeTh2Fe10 cuboctahedra, faces with fourteen FeTh3Fe9 cuboctahedra, and faces with two equivalent CTh2Fe4 octahedra. There are a spread of Fe–Fe bond distances ranging from 2.43–2.65 Å. In the fifth Fe site, Fe is bonded in a 2-coordinate geometry to one Th and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.38–2.73 Å. In the sixth Fe site, Fe is bonded in a single-bond geometry to eight Fe and one C atom. Both Fe–Fe bond lengths are 2.45 Å. The Fe–C bond length is 1.86 Å. In the seventh Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with sixteen FeTh3Fe9 cuboctahedra, corners with two equivalent CTh2Fe4 octahedra, edges with four FeTh3Fe9 cuboctahedra, an edgeedge with one CTh2Fe4 octahedra, and faces with fifteen FeTh3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–30°. The Fe–Fe bond length is 2.45 Å. C is bonded to two equivalent Th and four Fe atoms to form CTh2Fe4 octahedra that share corners with eighteen FeTh2Fe10 cuboctahedra, edges with four equivalent FeTh2Fe10 cuboctahedra, and faces with eight FeTh2Fe10 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Experimental and computational investigation of the bond energy of thorium dicarbonyl cation and theoretical elucidation of its isomerization mechanism to the thermodynamically most stable isomer, thorium oxide ketenylidene cation, OTh + CCO

Collision-induced dissociation (CID) of [Th,2C,2O] + with Xe is performed using a guided ion beam tandem mass spectrometer (GIBMS). The only products observed are ThCO + and Th + by sequential loss of CO ligands. The experimental findings and theoretical calculations support that the structure of [Th,2C,2O] + is the bent homoleptic thorium dicarbonyl cation, Th + (CO) 2 , having quartet spin, which is both thermodynamically and kinetically stable enough in the gas phase to be observed in our GIBMS instrument. Analysis of the kinetic energy-dependent cross sections for this CID reaction yields the first experimental determination of the bond dissociation energy (BDE) of (CO)Th + –CO at 0 K as 1.05 ± 0.09 eV. A theoretical BDE calculated at the CCSD(T) level with cc-pVXZ (X = T and Q) basis sets and a complete basis set (CBS) extrapolation is in very good agreement with the experimental result. Although the doublet spin bent thorium oxide ketenylidene cation, OTh + CCO, is calculated to be the most thermodynamically stable structure, it is not observed in our experiment where [Th,2C,2O] + is formed by association of Th + and CO in a direct current discharge flow tube (DC/FT) ion source. Potential energy profiles of both quartet and doublet spin are constructed to elucidate the isomerization mechanism of Th + (CO) 2 to OTh + CCO. The failure to observe OTh + CCO is attributed to a barrier associated with C–C bond formation, which makes OTh + CCO kinetically inaccessible under our experimental conditions. Furthermore, chemical bonding patterns in low-lying states of linear and bent Th + (CO) 2 and OTh + CCO isomers are also investigated.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC 71 BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μ h ) and electron (μ e ) mobilities, facilitate light-activated ITIC-Th to PC 71 BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC 71 BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (J SC ), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC 71 BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC 71 BM-rich aggregations and BHJ upper surface PC 71 BM composition. Further, these morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC 71 BM, compromising the J SC , FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μ e . DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC 71 BM. This structure–property understanding leads to a newly reported NFA blend with PCE near 17%.

14 SOLAR ENERGY↗
NASA NTRS1977

The effects of bandpass limiters on n-phase tracking systems

The combination of a bandpass limiter and an n-th power tracking loop is considered. Performance of the combination does not depend on the form of the nonlinear function used to create the n-th harmonic signal as long as some energy in that zone is produced. The order in which the limiter and n-th power nonlinearity occur is unimportant so that the results apply equally well to the n-phase Costas type of implementations of the n-th power loops. Closed form expressions for the signal suppression factors are obtained. Coherent and noncoherent SNR's out of the n-th power-limiter combination can be expressed in terms of two of these suppression factors. The loop SNR of an n-th power-limited phase locked loop is estimated by simply calculating the suppression factors for n-th and 2n-th power loops. Finally, n-th power phase locked loops without limiters are compared with similar loops with limiters; the limiter can actually enhance output SNR at moderate to large input SNR.

Butman, S. A.↗
NASA NTRS1977

The effects of bandpass limiters on n-phase tracking systems

The combination of a bandpass limiter and an n(th) power tracking loop is considered. It is shown that the performance of the combination does not depend on the form of the nonlinear function used to create the n(th) harmonic signal so long as some energy in that zone is produced. Furthermore, the order in which the limiter and n(th) power nonlinearity occur is unimportant so that the results apply equally well to the n-phase Costas type of implementation of the n(th) power loops. Closed form expressions for the signal suppression factors are obtained and it is shown that the coherent and noncoherent SNR's out of the n(th) power-limiter combination can be expressed in terms of two of these suppression factors. This later point enables one to estimate the loop SNR of an n(th) power-limiter phase locked loop by simply calculating the suppression factors for n(th) and 2n(th) power loops. Finally, n(th) power phase locked loops without limiters are compared with similar loops with limiters where it is shown that the presence of the limiter can actually enhance the output SNR at moderate to large values of input SNR.

Butman, S. A.↗
NASA NTRSDate not supplied

NASA’s Moon to Mars (M2M) Transit Habitat Refinement Point of Departure Design

As NASA prepares for the next human footsteps on the lunar surface, the Agency is already looking ahead to systems that will enable a sustained human presence on the lunar surface and mission to Mars, including a lunar Surface Habitat (SH) and Mars Transit Habitat (TH). This paper describes the latest NASA government reference design for the TH and how it will support NASA's Moon to Mars human exploration architecture. First, it will serve as a test and demonstration platform in lunar orbit, demonstrating capabilities required for long-duration microgravity human spaceflight as part of the lunar-Mars analog missions. Then, the TH will serve as a major Mars exploration element to support crew habitation during their transit from the Earth’s orbit to Mars and returning safely before TH’s return to a lunar orbit. This paper will cover several considerations contributing to the latest habitat design refinement, including the TH's concept of operations, system functional definition, subsystem assumptions, notional interior layouts, a detailed mass and volume breakdown, and identify future trade studies and analyses required to close identified technology/ development/architecture gaps. In addition to a technical description of the TH, this paper describes how the current TH government reference design will achieve many of the current lunar and Mars mission goals. Additionally, there are many assumed technological advances needed to support the prescribed mission phases leading up to the crewed mission to Mars in the late 2030s. The paper will describe many of the TH systems requiring further technology development and identify architectural solutions to achieve these mass, reliability, autonomy, and crew health targets. As a whole, the data shows the government reference TH design meeting the 26.4 metric ton launch /trans-Mars injection burn control mass limit outlined within NASA’s Moon to Mars Campaign. This is achievable near the desired timeframe with moderate strategic investments including maintainable life support systems, innovative structures configuration and materials, and system/ logistics packaging. The resulting design detail and data contained in this paper are intended to help teams across NASA and potential commercial, academic, or international partners understand the current performance targets of the Transit Habitat and vehicle interface considerations imposed by the latest Moon to Mars mission scope.

Habitation Systems↗
DOE OSTI2020

Materials Data on ThB2Ir3 by Materials Project

ThIr3B2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Th is bonded in a 12-coordinate geometry to two equivalent Th, twelve equivalent Ir, and six equivalent B atoms. Both Th–Th bond lengths are 3.25 Å. All Th–Ir bond lengths are 3.19 Å. All Th–B bond lengths are 3.17 Å. Ir is bonded in a distorted square co-planar geometry to four equivalent Th and four equivalent B atoms. All Ir–B bond lengths are 2.27 Å. B is bonded in a 6-coordinate geometry to three equivalent Th and six equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThCu5Sn by Materials Project

ThCu5Sn crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Th is bonded in a 6-coordinate geometry to fifteen Cu and four equivalent Sn atoms. There are a spread of Th–Cu bond distances ranging from 2.88–3.34 Å. There are a spread of Th–Sn bond distances ranging from 3.31–3.42 Å. There are four inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Th, seven Cu, and two equivalent Sn atoms to form a mixture of corner, edge, and face-sharing CuTh3Cu7Sn2 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.51–2.55 Å. There are one shorter (2.78 Å) and one longer (2.80 Å) Cu–Sn bond lengths. In the second Cu site, Cu is bonded in a 11-coordinate geometry to three equivalent Th, five Cu, and three equivalent Sn atoms. There are two shorter (2.59 Å) and one longer (3.07 Å) Cu–Cu bond lengths. There are one shorter (2.65 Å) and two longer (3.08 Å) Cu–Sn bond lengths. In the third Cu site, Cu is bonded to three equivalent Th, seven Cu, and two equivalent Sn atoms to form a mixture of corner, edge, and face-sharing CuTh3Cu7Sn2 cuboctahedra. The Cu–Cu bond length is 2.54 Å. Both Cu–Sn bond lengths are 2.83 Å. In the fourth Cu site, Cu is bonded in a 12-coordinate geometry to three equivalent Th, eight Cu, and one Sn atom. Both Cu–Cu bond lengths are 2.91 Å. The Cu–Sn bond length is 2.86 Å. Sn is bonded in a 1-coordinate geometry to four equivalent Th and ten Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThInCu5 by Materials Project

ThCu5In crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Th is bonded in a 6-coordinate geometry to fifteen Cu and four equivalent In atoms. There are a spread of Th–Cu bond distances ranging from 2.94–3.37 Å. There are a spread of Th–In bond distances ranging from 3.32–3.42 Å. There are four inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Th, seven Cu, and two equivalent In atoms to form a mixture of corner, edge, and face-sharing CuTh3In2Cu7 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.51–2.56 Å. There are one shorter (2.80 Å) and one longer (2.82 Å) Cu–In bond lengths. In the second Cu site, Cu is bonded in a 10-coordinate geometry to three equivalent Th, four Cu, and three equivalent In atoms. There are one shorter (2.56 Å) and one longer (2.63 Å) Cu–Cu bond lengths. There are one shorter (2.66 Å) and two longer (3.06 Å) Cu–In bond lengths. In the third Cu site, Cu is bonded to three equivalent Th, seven Cu, and two equivalent In atoms to form a mixture of corner, edge, and face-sharing CuTh3In2Cu7 cuboctahedra. The Cu–Cu bond length is 2.55 Å. Both Cu–In bond lengths are 2.85 Å. In the fourth Cu site, Cu is bonded in a 12-coordinate geometry to three equivalent Th, five Cu, and one In atom. The Cu–In bond length is 2.82 Å. In is bonded in a 1-coordinate geometry to four equivalent Th and ten Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2FeB10 by Materials Project

Th2FeB10 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Th is bonded in a 4-coordinate geometry to two equivalent Fe and twenty B atoms. Both Th–Fe bond lengths are 3.04 Å. There are a spread of Th–B bond distances ranging from 2.87–3.07 Å. Fe is bonded in a 12-coordinate geometry to four equivalent Th and eight B atoms. There are a spread of Fe–B bond distances ranging from 2.12–2.15 Å. There are four inequivalent B sites. In the first B site, B is bonded in a 9-coordinate geometry to four equivalent Th, one Fe, and four B atoms. There are a spread of B–B bond distances ranging from 1.69–1.78 Å. In the second B site, B is bonded in a 1-coordinate geometry to four equivalent Th and five B atoms. There are a spread of B–B bond distances ranging from 1.67–1.77 Å. In the third B site, B is bonded in a 9-coordinate geometry to four equivalent Th, one Fe, and four B atoms. There is one shorter (1.68 Å) and one longer (1.77 Å) B–B bond length. In the fourth B site, B is bonded in a 7-coordinate geometry to four equivalent Th, one Fe, and four B atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th3Al2 by Materials Project

Th3Al2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Th sites. In the first Th site, Th is bonded in a square co-planar geometry to four equivalent Al atoms. All Th–Al bond lengths are 3.24 Å. In the second Th site, Th is bonded in a 6-coordinate geometry to six equivalent Al atoms. There are two shorter (3.18 Å) and four longer (3.22 Å) Th–Al bond lengths. Al is bonded in a 9-coordinate geometry to eight Th and one Al atom. The Al–Al bond length is 2.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th3Ga2 by Materials Project

Th3Ga2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Th sites. In the first Th site, Th is bonded in a square co-planar geometry to four equivalent Ga atoms. All Th–Ga bond lengths are 3.20 Å. In the second Th site, Th is bonded in a 6-coordinate geometry to six equivalent Ga atoms. There are two shorter (3.14 Å) and four longer (3.20 Å) Th–Ga bond lengths. Ga is bonded in a 9-coordinate geometry to eight Th and one Ga atom. The Ga–Ga bond length is 2.69 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th5Sn3 by Materials Project

Th5Sn3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Th sites. In the first Th site, Th is bonded in a 6-coordinate geometry to six equivalent Sn atoms. All Th–Sn bond lengths are 3.34 Å. In the second Th site, Th is bonded in a 5-coordinate geometry to five equivalent Sn atoms. There are a spread of Th–Sn bond distances ranging from 3.22–3.48 Å. Sn is bonded in a 9-coordinate geometry to nine Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th3Ge2 by Materials Project

Th3Ge2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Th sites. In the first Th site, Th is bonded in a 6-coordinate geometry to six equivalent Ge atoms. There are two shorter (3.09 Å) and four longer (3.19 Å) Th–Ge bond lengths. In the second Th site, Th is bonded in a square co-planar geometry to four equivalent Ge atoms. All Th–Ge bond lengths are 3.19 Å. Ge is bonded in a 9-coordinate geometry to eight Th and one Ge atom. The Ge–Ge bond length is 2.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThB2Ru3 by Materials Project

ThRu3B2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Th is bonded in a 12-coordinate geometry to two equivalent Th, twelve equivalent Ru, and six equivalent B atoms. Both Th–Th bond lengths are 3.08 Å. All Th–Ru bond lengths are 3.18 Å. All Th–B bond lengths are 3.21 Å. Ru is bonded in a distorted square co-planar geometry to four equivalent Th and four equivalent B atoms. All Ru–B bond lengths are 2.22 Å. B is bonded in a 6-coordinate geometry to three equivalent Th and six equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Th8O19 by Materials Project

Th8La2O19 is alpha bismuth trifluoride-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.37–2.51 Å. In the second Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.41–2.46 Å. In the third Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.43–2.45 Å. In the fourth Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.43–2.45 Å. In the fifth Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are seven shorter (2.44 Å) and one longer (2.45 Å) Th–O bond lengths. In the sixth Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.43–2.45 Å. In the seventh Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.42–2.47 Å. In the eighth Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.37–2.50 Å. There are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.31–2.55 Å. In the second La3+ site, La3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of La–O bond distances ranging from 2.31–2.54 Å. There are nineteen inequivalent O2- sites. In the first O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the second O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the third O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the fourth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the fifth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the sixth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the seventh O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the eighth O2- site, O2- is bonded to two equivalent Th4+ and two equivalent La3+ atoms to form a mixture of edge and corner-sharing OLa2Th2 tetrahedra. In the ninth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the tenth O2- site, O2- is bonded to two equivalent Th4+ and two equivalent La3+ atoms to form a mixture of edge and corner-sharing OLa2Th2 tetrahedra. In the eleventh O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the twelfth O2- site, O2- is bonded to two equivalent Th4+ and two equivalent La3+ atoms to form OLa2Th2 tetrahedra that share corners with twelve OTh4 tetrahedra and edges with six OLa4 tetrahedra. In the thirteenth O2- site, O2- is bonded to two equivalent Th4+ and two equivalent La3+ atoms to form a mixture of edge and corner-sharing OLa2Th2 tetrahedra. In the fourteenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the fifteenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the sixteenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the seventeenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the eighteenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra. In the nineteenth O2- site, O2- is bonded to four Th4+ atoms to form a mixture of edge and corner-sharing OTh4 tetrahedra.

36 MATERIALS SCIENCE↗