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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

More Realistic Intermediate Depth Dry Firn Densification in the Energy Exascale Earth System Model (E3SM)

Abstract Earth system models account for seasonal snow cover, but many do not accommodate the deeper snowpack on ice sheets (aka firn) that slowly transforms to ice under accumulating snowfall. To accommodate and resolve firn depths of up to 60 m in the Energy Exascale Earth System Model's land surface model (ELM), we add 11 layers to its snowpack and evaluate three dry snow compaction equations in multi‐century simulations. After comparing results from ELM simulations (forced with atmospheric reanalysis) with empirical data, we find that implementing into ELM a two‐stage firn densification model produces more accurate dry firn densities at intermediate depths of 20–60 m. Compared to modeling firn using the equations in the (12 layer) Community Land Model (version 5), switching to the two‐stage firn densification model (with 16 layers) significantly decreases root‐mean‐square errors in upper 60 m dry firn densities by an average of 41 kg m −3 (31%). Simulations with three different firn density parameterizations show that the two‐stage firn densification model should be used for applications that prioritize accurate upper 60 m firn air content (FAC) in regions where the mean annual surface temperature is greater than roughly −31°C. Because snow metamorphism, firn density, and FAC are major components in modeling ice sheet surface albedo, melt water retention, and climatic mass balance, these developments advance broader efforts to simulate the response of land ice to atmospheric forcing in Earth system models.

58 GEOSCIENCES↗
DOE OSTI2021

Three-state harmonic models for photoinduced charge transfer

A widely used strategy for simulating the charge transfer between donor and acceptor electronic states in an all-atom anharmonic condensedphase system is based on invoking linear response theory to describe the system in terms of an effective spin-boson model Hamiltonian. Extending this strategy to photoinduced charge transfer processes requires also taking into consideration the ground electronic state in addition to the excited donor and acceptor electronic states. In this paper, we revisit the problem of describing such nonequilibrium processes in terms of an effective three-state harmonic model. We do so within the framework of nonequilibrium Fermi’s golden rule (NE-FGR) in the context of photoinduced charge transfer in the carotenoid–porphyrin–C 60 (CPC 60 ) molecular triad dissolved in explicit tetrahydrofuran (THF). To this end, we consider different ways for obtaining a three-state harmonic model from the equilibrium autocorrelation functions of the donor–acceptor, donor–ground, and acceptor–ground energy gaps, as obtained from all-atom molecular dynamics simulations of the CPC 60 /THF system. The quantum-mechanically exact time-dependent NE-FGR rate coefficients for two different charge transfer processes in two different triad conformations are then calculated using the effective three-state model Hamiltonians as well as a hierarchy of more approximate expressions that lead to the instantaneous Marcus theory limit. Our results show that the photoinduced charge transfer in CPC 60 /THF can be described accurately by the effective harmonic three-state models and that nuclear quantum effects are small in this system.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Scalable learning of potentials to predict time-dependent Hartree–Fock dynamics

We propose a framework to learn the time-dependent Hartree–Fock (TDHF) inter-electronic potential of a molecule from its electron density dynamics. Although the entire TDHF Hamiltonian, including the inter-electronic potential, can be computed from first principles, we use this problem as a testbed to develop strategies that can be applied to learn a priori unknown terms that arise in other methods/approaches to quantum dynamics, e.g., emerging problems such as learning exchange–correlation potentials for time-dependent density functional theory. We develop, train, and test three models of the TDHF inter-electronic potential, each parameterized by a four-index tensor of size up to 60 × 60 × 60 × 60. Two of the models preserve Hermitian symmetry, while one model preserves an eight-fold permutation symmetry that implies Hermitian symmetry. Across seven different molecular systems, we find that accounting for the deeper eight-fold symmetry leads to the best-performing model across three metrics: training efficiency, test set predictive power, and direct comparison of true and learned inter-electronic potentials. All three models, when trained on ensembles of field-free trajectories, generate accurate electron dynamics predictions even in a field-on regime that lies outside the training set. To enable our models to scale to large molecular systems, we derive expressions for Jacobian-vector products that enable iterative, matrix-free training.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Partitioning uncertainty in projections of Arctic sea ice

Abstract Improved knowledge of the contributing sources of uncertainty in projections of Arctic sea ice over the 21st century is essential for evaluating impacts of a changing Arctic environment. Here, we consider the role of internal variability, model structure and emissions scenario in projections of Arctic sea-ice area (SIA) by using six single model initial-condition large ensembles and a suite of models participating in Phase 5 of the Coupled Model Intercomparison Project. For projections of September Arctic SIA change, internal variability accounts for as much as 40%–60% of the total uncertainty in the next decade, while emissions scenario dominates uncertainty toward the end of the century. Model structure accounts for 60%–70% of the total uncertainty by mid-century and declines to 30% at the end of the 21st century in the summer months. For projections of wintertime Arctic SIA change, internal variability contributes as much as 50%–60% of the total uncertainty in the next decade and impacts total uncertainty at longer lead times when compared to the summertime. In winter, there exists a considerable scenario dependence of model uncertainty with relatively larger model uncertainty under strong forcing compared to weak forcing. At regional scales, the contribution of internal variability can vary widely and strongly depends on the calendar month and region. For wintertime SIA change in the Greenland-Iceland-Norwegian and Barents Seas, internal variability contributes 60%–70% to the total uncertainty over the coming decades and remains important much longer than in other regions. We further find that the relative contribution of internal variability to total uncertainty is state-dependent and increases as sea ice volume declines. These results demonstrate that internal variability is a significant source of uncertainty in projections of Arctic sea ice.

Bonan, David B. (ORCID:0000000338676009)↗
DOE OSTI2021

Where’s Swimmy?: Mining unique color features buried in galaxies by deep anomaly detection using Subaru Hyper Suprime-Cam data

Abstract We present the Swimmy (Subaru WIde-field Machine-learning anoMalY) survey program, a deep-learning-based search for unique sources using multicolored (grizy) imaging data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). This program aims to detect unexpected, novel, and rare populations and phenomena, by utilizing the deep imaging data acquired from the wide-field coverage of the HSC-SSP. This article, as the first paper in the Swimmy series, describes an anomaly detection technique to select unique populations as “outliers” from the data-set. The model was tested with known extreme emission-line galaxies (XELGs) and quasars, which consequently confirmed that the proposed method successfully selected $\sim\!\! 60\%$–$70\%$ of the quasars and $60\%$ of the XELGs without labeled training data. In reference to the spectral information of local galaxies at z = 0.05–0.2 obtained from the Sloan Digital Sky Survey, we investigated the physical properties of the selected anomalies and compared them based on the significance of their outlier values. The results revealed that XELGs constitute notable fractions of the most anomalous galaxies, and certain galaxies manifest unique morphological features. In summary, deep anomaly detection is an effective tool that can search rare objects, and, ultimately, unknown unknowns with large data-sets. Further development of the proposed model and selection process can promote the practical applications required to achieve specific scientific goals.

Astronomy & Astrophysics↗
DOE OSTI2021

Optically and thermally driven huge lattice orbital and spin angular momenta from spinning fullerenes

Lattice vibration in solids may carry angular momentum. But unlike the intrinsic spin of electrons, the lattice vibration is rarely rotational. To induce angular momentum, one needs to find a material that can accommodate a twisted normal mode, two orthogonal modes, or excitation of magnons. If excitation is too strong, one may exceed the Lindemann limit, so the material melts. Therefore these methods are not ideal. Here, we theoretically propose a route to phonon angular momentum in a molecular crystal C 60 . We find that a single laser pulse is able to inject a significant amount of angular momentum to C 60 , and the momentum transfer is helicity dependent. Changing from right-circularly polarized light to left-circularly polarized light switches the direction of phonon angular momentum. On the ultrafast timescale, the orbital angular momentum change closely resembles the displacive excitation of coherent phonons, with a cosine-function dependence on time, different from the spin counterpart. Atomic displacements, even under strong laser excitation, remain far below the Lindemann criterion. Under thermal excitation, spinning C 60 even at room temperature generates a huge angular momentum close to several hundred h¯. Our finding opens the door to a large group of fullerenes, from C 60 , C 70 to their endohedral derivatives, where angular momentum can be generated through light or temperature. Furthermore, this paves the way to the phononic control electronic spin and harvesting thermal energy through phonon angular momentum.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2026

Corn and Switchgrass Derived Sustainable Aviation Fuel Carbon Intensity

The production and use of sustainable aviation fuel (SAF) could lower aviation's carbon footprint. Feedstock agricultural management can optimize—or potentially determine—SAF sustainability and profitability, but long-term SAF feedstock comparisons are limited. Life cycle assessments (LCA) are commonly used to estimate the carbon intensity of producing SAF from emerging feedstocks due to the limited availability of long-term, primary field data. We quantified the agricultural phase and well-to-wake (WTWa) carbon intensities of producing SAF from no-till, continuous corn (Zea mays L.) under 120 kg N ha−1 year−1 (120 N corn) and switchgrass (Panicum virgatum L.) under 60 or 120 kg N ha−1 year−1 (60 N and 120 N SWG, respectively) via LCAs based on measured data from a long-term (1998-present) field experiment on marginally productive cropland located in Eastern NE, USA. Measured data included crop productivity, long-term changes in soil organic carbon (SOC) stocks (0–150 cm), annual soil N2O emissions, and field management practices. Both 120 N corn (2078 L ha−1) and 120 N SWG (1752 L ha−1) produced more SAF than 60 N SWG (1229 L ha−1) (p < 0.0001). However, making SAF from corn had greater life cycle GHG emissions (i.e., WTWa carbon intensity) than making SAF from 120 N and 60 N SWG (61.5 > −14.5 and −27.5 g CO2e MJ−1 SAF, respectively; p = 0.0007), primarily due to SOC accrual during crop production. Here, we demonstrate that agricultural management (e.g., crop type, fertilizer use) can determine the sustainably and productivity of producing SAF by using long-term, measured field data in LCAs.

carbon intensity↗
DOE OSTI2020

High-Pressure Hydrofullerites

This paper is a brief summary of the results of long-term experimental studies of C 60 H x hydrofullerites with a hydrogen content of up to x ~ 60 or more, obtained by loading C 60 fullerites with hydrogen at pressures up to 9 GPa and temperatures up to 500°C. Basically, this is an overview of already published data. Some results for hydrofullerites with compositions of x ~ 60 and x ~ 90 are presented for the first time.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A Direct Ammonia Fuel Cell with a KOH-Free Anode Feed Generating 180 mW cm −2 at 120 °C

The motivations to operate the direct ammonia fuel cell (DAFC) with no addition of aqueous base, include facilitated fuel management and prevention of corrosion and shunt currents in the DAFC stack. We describe here a polymer electrolyte DAFC, operating at a cell temperature (T cell ) of 120 °C on ammonia and water alone as anode feed, that demonstrated peak power of 180 mW cm −2 —a record for this type of fuel cell. We offer a detailed analysis of polarization curves recorded for PE-DAFCs in the T cell range of 60 °C–120 °C, allowing to estimate the effects of KOH-free operation on the ionic and faradaic resistances, R i and R F , that determine together the value of R app , CL – an , the apparent resistance of the anode catalyst layer. The latter resistance drops ten times between 60 °C and 120 °C as result mainly of the drop in R F . Consequently, DAFC performance at T cell > 100 °C improves substantially, including the cell performance on a KOH-free anode feed. The demsontrated performance levels reported here for KOH-free DAFCs support further development of this type of ammonia/air fuel cells.

Achrai, Ben↗
DOE OSTI2022

Quantification of Dead Lithium on Graphite Anode under Fast Charging Conditions

A series of computational and experimental studies were conducted to understand the onset of lithium plating and subsequent quantification of dead lithium on graphite electrodes in the design of fast charging batteries. The experiments include titration and relaxation studies for detecting initiation of lithium metal plating for various SOC and C-rates, which are compared against the thermodynamically consistent phase field computational results. The collaborative study on "model graphite electrode" with 2.18 mAh cm-2 nominal capacity at 25 degrees C demonstrates: (1) the macroscopic voltage response during relaxation studies indicate the reintercalation of plated lithium into the graphite anode; (2) for SOC below 60% and low C-Rates, there is no dead lithium; (3) for SOC between 60% to 80%, and C-Rates in the range of 4C-6C show dead lithium both in experiments and simulations; (4) at 100% SOC and 4C-6C rates, large amounts of dead lithium are observed. The study presented here allows us to evaluate the effects of the physical properties of the electrochemical system on plating and stripping kinetics and the amount of dead lithium on graphite electrodes, which determines the cell capacity loss under fast charge.

batteries↗
DOE OSTI2023

Soil water content, matric potential, carbon dioxide and oxygen concentrations, Oct 2018-Dec 2021, Slate River Floodplain, Crested Butte, Colorado

This data package includes a time series of soil sensor data (temperature, water content, bulk electrical conductivity, porewater dissolved oxygen and porewater dissolved carbon dioxide) in a vertical profile from the Slate River floodplain outside Crested Butte, Colorado, a focus field site for the SLAC Floodplain Hydro-Biogeochemistry SFA. The data was generated as part of the work targeting the overarching research question for the SLAC SFA: How do ubiquitous subsurface interfaces mediate molecular-scale biogeochemical processes and groundwater quality in floodplains and watersheds? The package includes: (1) soil temperature, volumetric water content and electrical conductivity at 40, 60 and 82.5 cm depth; (2) soil matric potential at 40, 60, 79 and 100 cm depth; (3) soil CO2 concentrations at 40, 60 and 82.5 cm depth; and (4) soil oxygen concentrations at 60, 82.5, 100, 135, 170 and 182 cm depth. Both the carbon dioxide and oxygen sensors are optical sensors that can measure the partial pressure of oxygen in both saturated and unsaturated conditions. Unfortunately, soil CO2 in the profile is unexpectedly high and above the sensor calibration range (0-25,000 ppm). In addition, soil CO2 sensors failed within a year of deployment, so we only report CO2 data from 2019-2020.Within the data package, "FLMD.csv" describes file-level metadata and "dd.csv" defines column headers and universal terms across the dataset. The data package includes 4 "*data.csv" files, one for each calendar year in the dataset. Each "*data.csv" file has a corresponding "*_InstallationMethods.csv" file that describes the location, sensor model, sensor serial number and other metadata corresponding for each measured parameter. Because sensors have been added over time, not every sensor has data dating back to Oct 2018. Note that there is a data gap over winter 2019-2020 due to a power outage. While this repository currently only contains data through December 2021, the dataset will be updated as additional years are collected and processed.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Post-Release Survivorship in a New Population of Blanding's Turtles Established Using Headstarted and Directly Released Turtles

Blanding’s Turtles are facing a variety of anthropogenic threats that decrease population viability. We initiated a project to establish a new population of Blanding’s Turtles on a National Wildlife Refuge in Massachusetts using hatchlings obtained from a nearby robust donor population. We released 440 head-started individuals and 401 directly-released hatchlings between 2007–2013 and conducted multiple years of post-release monitoring via aquatic trapping to estimate survival. Between 2014–2021 we released an additional 824 head-started and 433 directly-released individuals and conducted one year of aquatic trapping in 2021 to estimate population size. First year post-release survival of head-started turtles was six times that of directly-released hatchlings (0.72 vs. 0.12, respectively), but annual survival of both groups was 0.78–0.90 in subsequent years. Only 19% of turtles released at <60 mm carapace length (CL) were subsequently recaptured compared to 60% of those released at ≥60 mm CL, supporting 60 mm CL as a target minimum release size. The mean population estimates using two different study designs were 164 and 202, with 91 individuals encountered. Now that turtles released early in the project are approaching reproductive maturity, we recommend resampling and expanding trapping efforts to include more wetlands to assess long-term survival, abundance, and distribution of Blanding’s Turtles in this newly established population. Furthermore, our results, combined with other evaluations of head-starting across the species’ range, add credence to the use of head-starting as a population recovery tool for Blanding’s Turtles.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

The impact of temperature, chlorides and sulfate-reducing bacteria on the corrosion of steel in soil

Here, this investigation aimed to study the corrosion performance of low-carbon steel in a soil environment at different temperatures. The steel specimens in the soil were treated at three temperatures: 5, 25 and 60°C. The specimens were embedded in chloride-free soil for 21 days, and then 3.5% (by weight) sodium chloride (NaCl) was added to the soil. The specimens were then kept in the chloride-contaminated soil for 54 days. The results of electrochemical experiments showed superior corrosion performance of the specimens at 60°C, which had the lowest corrosion activity, followed by the specimens at 5 and 25°C. The slow nature of the kinetics of the corrosion reactions at 5°C compared with that at ambient temperature was the reason for this improvement at 5°C. The lower number of microorganisms, including sulfate-reducing bacteria, in the soil at 60°C compared with that at the other temperatures was attributed to the lower corrosion activity of steel in the soil at 60°C compared with the corrosion activity of steel in the soil at other temperatures.

99 - GENERAL AND MISCELLANEOUS↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are seven inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.97–2.12 Å. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Mg–O bond distances ranging from 1.94–2.00 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.95 Å) and three longer (1.96 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There is three shorter (1.97 Å) and one longer (1.98 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. There are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent MgO6 octahedra and corners with eight AlO6 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Al–O bond distances ranging from 1.79–1.83 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.97 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four equivalent AlO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with four equivalent MgO6 octahedra. There is two shorter (1.81 Å) and four longer (2.04 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–2.00 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–2.00 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is one shorter (1.93 Å) and five longer (1.94 Å) Al–O bond length. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.93 Å) and three longer (1.94 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is two shorter (1.93 Å) and four longer (1.94 Å) Al–O bond length. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two Al3+ atoms. In the second O2- site, O2- is bonded to three Mg2+ and one Al3+ atom to form distorted corner-sharing OMg3Al tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two OMgAl3 tetrahedra, corners with six OMgAl3 trigonal pyramids, edges with two OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the tenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two equivalent OMgAl3 tetrahedra, corners with six OMgAl3 trigonal pyramids, edges with two equivalent OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the nineteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twentieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are ten inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.93 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.93 Å) and one longer (1.98 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.00 Å) and three longer (2.10 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.09 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.97 Å) Mg–O bond length. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mg–O bond lengths are 1.96 Å. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There is three shorter (1.97 Å) and one longer (2.00 Å) Mg–O bond length. In the ninth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is three shorter (1.96 Å) and one longer (1.98 Å) Mg–O bond length. In the tenth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are ten inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.95 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is one shorter (1.84 Å) and three longer (1.85 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.93–1.95 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.99 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.83 Å) and one longer (1.86 Å) Al–O bond length. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twentieth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce10Y22O53 by Materials Project

Ce10Y22O53 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Ce sites. In the first Ce site, Ce is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ce–O bond distances ranging from 2.26–2.41 Å. In the second Ce site, Ce is bonded to seven O atoms to form distorted CeO7 pentagonal bipyramids that share a cornercorner with one YO6 octahedra, corners with two CeO7 pentagonal bipyramids, edges with three YO6 octahedra, and edges with five YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. There are a spread of Ce–O bond distances ranging from 2.27–2.42 Å. In the third Ce site, Ce is bonded to seven O atoms to form distorted CeO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with five YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 47–59°. There are a spread of Ce–O bond distances ranging from 2.20–2.55 Å. In the fourth Ce site, Ce is bonded to seven O atoms to form distorted CeO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, a cornercorner with one YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, an edgeedge with one CeO6 octahedra, edges with three YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. There are a spread of Ce–O bond distances ranging from 2.24–2.48 Å. In the fifth Ce site, Ce is bonded to seven O atoms to form distorted CeO7 pentagonal bipyramids that share a cornercorner with one YO6 octahedra, corners with two CeO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. There are a spread of Ce–O bond distances ranging from 2.24–2.38 Å. In the sixth Ce site, Ce is bonded in a body-centered cubic geometry to eight O atoms. There are a spread of Ce–O bond distances ranging from 2.27–2.64 Å. In the seventh Ce site, Ce is bonded to six O atoms to form distorted CeO6 octahedra that share corners with three YO6 octahedra, corners with three YO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, an edgeedge with one YO6 octahedra, edges with two CeO7 pentagonal bipyramids, and edges with two YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Ce–O bond distances ranging from 2.20–2.38 Å. In the eighth Ce site, Ce is bonded to seven O atoms to form distorted CeO7 pentagonal bipyramids that share a cornercorner with one YO6 octahedra, corners with two CeO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. There are a spread of Ce–O bond distances ranging from 2.21–2.40 Å. In the ninth Ce site, Ce is bonded to six O atoms to form distorted CeO6 octahedra that share corners with three YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, corners with two CeO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Ce–O bond distances ranging from 2.19–2.37 Å. In the tenth Ce site, Ce is bonded to six O atoms to form distorted CeO6 octahedra that share corners with four YO6 octahedra, corners with two YO7 pentagonal bipyramids, an edgeedge with one YO6 octahedra, edges with two CeO7 pentagonal bipyramids, and edges with two YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Ce–O bond distances ranging from 2.22–2.32 Å. There are twenty-two inequivalent Y sites. In the first Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, a cornercorner with one YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, edges with three YO6 octahedra, edges with three CeO7 pentagonal bipyramids, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Y–O bond distances ranging from 2.27–2.53 Å. In the second Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, corners with three YO7 pentagonal bipyramids, an edgeedge with one YO6 octahedra, an edgeedge with one YO7 pentagonal bipyramid, and edges with two CeO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–60°. There are a spread of Y–O bond distances ranging from 2.24–2.33 Å. In the third Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with three YO6 octahedra, a cornercorner with one CeO7 pentagonal bipyramid, a cornercorner with one YO7 pentagonal bipyramid, edges with two YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Y–O bond distances ranging from 2.24–2.40 Å. In the fourth Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, corners with three YO7 pentagonal bipyramids, an edgeedge with one YO6 octahedra, an edgeedge with one YO7 pentagonal bipyramid, and edges with three CeO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Y–O bond distances ranging from 2.25–2.33 Å. In the fifth Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, corners with three CeO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, an edgeedge with one YO6 octahedra, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 59°. There are a spread of Y–O bond distances ranging from 2.23–2.38 Å. In the sixth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, edges with two YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 47–53°. There are a spread of Y–O bond distances ranging from 2.26–2.59 Å. In the seventh Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share corners with two YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, an edgeedge with one CeO6 octahedra, an edgeedge with one YO6 octahedra, edges with two CeO7 pentagonal bipyramids, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Y–O bond distances ranging from 2.26–2.45 Å. In the eighth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, a cornercorner with one YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, edges with two YO6 octahedra, edges with two CeO7 pentagonal bipyramids, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Y–O bond distances ranging from 2.29–2.47 Å. In the ninth Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, a cornercorner with one CeO7 pentagonal bipyramid, corners with two YO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, and edges with three YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Y–O bond distances ranging from 2.25–2.39 Å. In the tenth Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, corners with three YO7 pentagonal bipyramids, edges with three YO6 octahedra, an edgeedge with one YO7 pentagonal bipyramid, and edges with two CeO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Y–O bond distances ranging from 2.23–2.37 Å. In the eleventh Y site, Y is bonded to six O atoms to form distorted YO6 octahedra that share a cornercorner with one CeO6 octahedra, a cornercorner with one YO6 octahedra, corners with four YO7 pentagonal bipyramids, an edgeedge with one CeO6 octahedra, edges with two YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with two YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Y–O bond distances ranging from 2.24–2.42 Å. In the twelfth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share corners with two YO6 octahedra, a cornercorner with one YO7 pentagonal bipyramid, edges with two YO6 octahedra, edges with three CeO7 pentagonal bipyramids, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Y–O bond distances ranging from 2.28–2.46 Å. In the thirteenth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, a cornercorner with one YO6 octahedra, a cornercorner with one CeO7 pentagonal bipyramid, edges with four YO6 octahedra, an edgeedge with one CeO7 pentagonal bipyramid, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Y–O bond distances ranging from 2.28–2.48 Å. In the fourteenth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, edges with three CeO7 pentagonal bipyramids, and edges with five YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Y–O bond distances ranging from 2.28–2.44 Å. In the fifteenth Y site, Y is bonded to seven O atoms to form distorted YO7 pentagonal bipyramids that share corners with two YO6 octahedra, an edgeedge with one CeO6 octahedra, an edgeedge with one YO6 octahedra, edges with two CeO7 pentagonal bipyramids, and edges with five YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 51–52°. There are a spread of Y–O bond distances ranging from 2.30–2.50 Å. In the sixteenth Y site, Y is bonded to six O atoms to form YO6 octahedra that share a cornercorner with one CeO6 octahedra, corners with two YO6 octahedra, corners with two YO7 pentagonal bipyramids, an edgeedge with one YO6 octahedra, edges with two YO7 pentagonal bipyramids, and edges with three CeO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Y–O bond distances ranging from 2.24–2.33 Å. In the seventeenth Y site, Y is bonded to six O atoms to form YO6 octahedra that share corners with two CeO6 octahedra, corners with two YO6 octahedra, a cornercorner with one CeO7 pentagonal bipyramid, a cornercorner with one YO7 pentagonal bipyramid, edges with two YO6 octahedra, and edges with four YO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 55–59

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na7In3Se8 by Materials Project

Na7In3Se8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with seven NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, corners with five InSe4 tetrahedra, edges with six NaSe6 octahedra, edges with three InSe4 tetrahedra, and a faceface with one NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 18–52°. There are a spread of Na–Se bond distances ranging from 2.88–3.54 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with seven NaSe6 octahedra, corners with two equivalent NaSe4 tetrahedra, corners with four InSe4 tetrahedra, edges with six NaSe6 octahedra, edges with three InSe4 tetrahedra, and a faceface with one NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 15–53°. There are a spread of Na–Se bond distances ranging from 2.88–3.65 Å. In the third Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with seven NaSe6 octahedra, corners with two equivalent NaSe4 tetrahedra, corners with four InSe4 tetrahedra, edges with six NaSe6 octahedra, an edgeedge with one NaSe4 tetrahedra, edges with two InSe4 tetrahedra, and a faceface with one NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 11–60°. There are a spread of Na–Se bond distances ranging from 2.93–3.61 Å. In the fourth Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with seven NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, corners with five InSe4 tetrahedra, edges with six NaSe6 octahedra, an edgeedge with one InSe4 tetrahedra, edges with two equivalent NaSe4 tetrahedra, and a faceface with one NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–60°. There are a spread of Na–Se bond distances ranging from 2.96–3.49 Å. In the fifth Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with ten NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, corners with three InSe4 tetrahedra, edges with two NaSe6 octahedra, an edgeedge with one NaSe4 tetrahedra, edges with three InSe4 tetrahedra, and faces with two NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 36–60°. There are a spread of Na–Se bond distances ranging from 2.89–3.27 Å. In the sixth Na1+ site, Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with ten NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, corners with three InSe4 tetrahedra, edges with two NaSe6 octahedra, an edgeedge with one NaSe4 tetrahedra, edges with three InSe4 tetrahedra, and faces with two NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 34–60°. There are a spread of Na–Se bond distances ranging from 2.90–3.38 Å. In the seventh Na1+ site, Na1+ is bonded to four Se2- atoms to form NaSe4 tetrahedra that share corners with eight NaSe6 octahedra, corners with two InSe4 tetrahedra, edges with five NaSe6 octahedra, and an edgeedge with one InSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–77°. There are a spread of Na–Se bond distances ranging from 2.89–2.94 Å. There are three inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form InSe4 tetrahedra that share corners with eight NaSe6 octahedra, corners with two InSe4 tetrahedra, edges with five NaSe6 octahedra, and an edgeedge with one NaSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–66°. There are a spread of In–Se bond distances ranging from 2.56–2.70 Å. In the second In3+ site, In3+ is bonded to four Se2- atoms to form InSe4 tetrahedra that share corners with eight NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, a cornercorner with one InSe4 tetrahedra, edges with five NaSe6 octahedra, and an edgeedge with one InSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–68°. There are a spread of In–Se bond distances ranging from 2.58–2.68 Å. In the third In3+ site, In3+ is bonded to four Se2- atoms to form InSe4 tetrahedra that share corners with eight NaSe6 octahedra, a cornercorner with one NaSe4 tetrahedra, a cornercorner with one InSe4 tetrahedra, edges with five NaSe6 octahedra, and an edgeedge with one InSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–69°. There are a spread of In–Se bond distances ranging from 2.58–2.68 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Na1+ and two equivalent In3+ atoms to form distorted SeNa4In2 pentagonal pyramids that share a cornercorner with one SeNa5In pentagonal pyramid and edges with three SeNa4In2 pentagonal pyramids. In the second Se2- site, Se2- is bonded in a 7-coordinate geometry to six Na1+ and one In3+ atom. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to five Na1+ and two In3+ atoms. In the fourth Se2- site, Se2- is bonded in a 7-coordinate geometry to five Na1+ and two In3+ atoms. In the fifth Se2- site, Se2- is bonded in a 7-coordinate geometry to six Na1+ and one In3+ atom. In the sixth Se2- site, Se2- is bonded in a 6-coordinate geometry to five Na1+ and one In3+ atom. In the seventh Se2- site, Se2- is bonded to four Na1+ and two equivalent In3+ atoms to form distorted SeNa4In2 pentagonal pyramids that share a cornercorner with one SeNa5In pentagonal pyramid and edges with three SeNa4In2 pentagonal pyramids. In the eighth Se2- site, Se2- is bonded to five Na1+ and one In3+ atom to form a mixture of distorted edge and corner-sharing SeNa5In pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TiF6 by Materials Project

Na2TiF6 is zeta iron carbide-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six F1- atoms to form NaF6 octahedra that share corners with four equivalent TiF6 octahedra, corners with six NaF6 octahedra, and an edgeedge with one TiF6 octahedra. The corner-sharing octahedra tilt angles range from 45–60°. There are a spread of Na–F bond distances ranging from 2.34–2.47 Å. In the second Na1+ site, Na1+ is bonded to six F1- atoms to form distorted NaF6 octahedra that share corners with two equivalent TiF6 octahedra, corners with six NaF6 octahedra, and edges with two equivalent TiF6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Na–F bond distances ranging from 2.25–2.37 Å. In the third Na1+ site, Na1+ is bonded to six F1- atoms to form distorted NaF6 octahedra that share corners with two equivalent TiF6 octahedra, corners with six NaF6 octahedra, and edges with two equivalent TiF6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Na–F bond distances ranging from 2.26–2.37 Å. In the fourth Na1+ site, Na1+ is bonded to six F1- atoms to form NaF6 octahedra that share corners with four equivalent TiF6 octahedra, corners with six NaF6 octahedra, and an edgeedge with one TiF6 octahedra. The corner-sharing octahedra tilt angles range from 46–60°. There are a spread of Na–F bond distances ranging from 2.34–2.47 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six F1- atoms to form TiF6 octahedra that share corners with six NaF6 octahedra and edges with three NaF6 octahedra. The corner-sharing octahedra tilt angles range from 45–46°. All Ti–F bond lengths are 1.90 Å. In the second Ti4+ site, Ti4+ is bonded to six F1- atoms to form TiF6 octahedra that share corners with six NaF6 octahedra and edges with three NaF6 octahedra. The corner-sharing octahedral tilt angles are 50°. All Ti–F bond lengths are 1.89 Å. There are nine inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the fifth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the sixth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the seventh F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the eighth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom. In the ninth F1- site, F1- is bonded in a distorted trigonal planar geometry to two Na1+ and one Ti4+ atom.

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