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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Recent advances in polymeric facilitated transport membranes for carbon dioxide separation and hydrogen purification

Membrane and membrane process have been widely considered as one of the best candidates for mitigating CO 2 emissions from the combustion or utilization of fossil fuels. Various amine-containing polymers constitute an important class of membranes, where the highly selective CO 2 transport is achieved by the facilitated transport mechanism. In this review, the amine–CO 2 chemistry is discussed in conjunction with the mechanism of the reaction-mediated CO 2 transport. A wide variety of amine-containing polymers are discussed based on two synthesis motifs: (a) polyamines with amino groups covalently bound to the polymer backbone and (b) small molecule amines embedded in a polymer matrix. This review concludes with the remarks on the facilitated transport membranes for post-combustion carbon capture (CO 2 /N 2 ) and hydrogen purification (CO 2 /H 2 ).

42 ENGINEERING↗
NASA NTRS1972

Space shuttle system program definition. Volume 4: Cost and schedule report

The supporting cost and schedule data for the second half of the Space Shuttle System Phase B Extension Study is summarized. The major objective for this period was to address the cost/schedule differences affecting final selection of the HO orbiter space shuttle system. The contending options under study included the following booster launch configurations: (1) series burn ballistic recoverable booster (BRB), (2) parallel burn ballistic recoverable booster (BRB), (3) series burn solid rocket motors (SRM's), and (4) parallel burn solid rocket motors (SRM's). The implications of varying payload bay sizes for the orbiter, engine type for the ballistics recoverable booster, and SRM motors for the solid booster were examined.

Source record↗
DOE OSTI2020

Materials Data on Ho4(B2O5)3 by Materials Project

Ho4(B2O5)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.22–2.68 Å. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.25–2.63 Å. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form a mixture of edge and corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.55 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.44–1.52 Å. In the third B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.51 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent B3+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom. In the third O2- site, O2- is bonded in a distorted L-shaped geometry to two equivalent Ho3+ and two equivalent B3+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two B3+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Ho3+ and two B3+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two B3+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Molecular complexes of low-valent ƒ-elements from lanthanum to californium

This review outlines the structure and chemistry of divalent lanthanides and actinides in small molecule systems, focusing on the less accessible divalent lanthanides such as the configurational crossover (Dy 2+ , Nd 2+ ) and non-traditional lanthanides(II) (La 2+ , Ce 2+ , Pr 2+ , Gd 2+ , Tb 2+ , Ho 2+ , Er 2+ , and Lu 2+ ) and the rarely accessible actinides(II). Expansive progress, including recent synthetic firsts in low-oxidation state ƒ-block chemistry, are reviewed and analyzed to build knowledge for future synthetic efforts.

Wineinger, Hannah B. [Colorado School of Mines, Go↗
DOE OSTI2020

Materials Data on Ho(BO2)3 by Materials Project

Ho(BO2)3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.27–2.59 Å. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.28–2.54 Å. In the third Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.27–2.84 Å. In the fourth Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.32–2.64 Å. There are six inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.53 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There is one shorter (1.47 Å) and three longer (1.48 Å) B–O bond length. In the third B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.54 Å. In the fourth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.54 Å. In the fifth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.53 Å. In the sixth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.52 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ho3+ and two B3+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two B3+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Ho3+ and two equivalent B3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two B3+ atoms. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to three B3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two B3+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Ho3+ and two B3+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ho3+ and two B3+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two Ho3+ and two B3+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two equivalent B3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ho3+ and two equivalent B3+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom. In the thirteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ho3+ and two equivalent B3+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ho3+ and two equivalent B3+ atoms. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2015

Advances in High Energy Solid-State Pulsed 2-Micron Lidar Development for Ground and Airborne Wind, Water Vapor and CO2 Measurements

NASA Langley Research Center has a long history of developing 2-micron lasers. From fundamental spectroscopy research, theoretical prediction of new materials, laser demonstration and engineering of lidar systems, it has been a very successful program spanning around two decades. Successful development of 2-micron lasers has led to development of a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement with an unprecedented laser pulse energy of 250 millijoules in a rugged package. This high pulse energy is produced by a Ho:Tm:LuLiF laser with an optical amplifier. While the lidar is meant for use as an airborne instrument, ground-based tests were carried out to characterize performance of the lidar. Atmospheric measurements will be presented, showing the lidar's capability for wind measurement in the atmospheric boundary layer and free troposphere. Lidar wind measurements are compared to a balloon sonde, showing good agreement between the two sensors. Similar architecture has been used to develop a high energy, Ho:Tm:YLF double-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument based on direct detection technique that provides atmospheric column CO2 measurements. This instrument has been successfully used to measure atmospheric CO2 column density initially from a ground mobile lidar trailer, and then it was integrated on B-200 plane and 20 hours of flight measurement were made from an altitude ranging 1500 meters to 8000 meters. These measurements were compared to in-situ measurements and National Oceanic and Atmospheric Administration (NOAA) airborne flask measurement to derive the dry mixing ratio of the column CO2 by reflecting the signal by various reflecting surfaces such as land, vegetation, ocean surface, snow and sand. The lidar measurements when compared showed a very agreement with in-situ and airborne flask measurement. NASA Langley Research Center is currently developing a triple-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument for simultaneous measurement of water vapor and carbon-dioxide column density measurement from an air-borne platform. This presentation will give an overview of the 2 decades of 2-micron coherent and direction detection of laser/lidar development at NASA Langley Research Center and will present the ground and airborne wind and column CO2 measurement intercomparison with in-situ, balloon and flask measurements.

Singh, Upendra N.↗
DOE OSTI2020

Materials Data on KB6(HO)6 by Materials Project

KB6(H2O3)2H2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four dihydrogen molecules and one KB6(H2O3)2 framework. In the KB6(H2O3)2 framework, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.72–2.99 Å. There are six inequivalent B sites. In the first B site, B is bonded in a single-bond geometry to one B and one O atom. The B–B bond length is 1.63 Å. The B–O bond length is 1.24 Å. In the second B site, B is bonded in a 5-coordinate geometry to five B atoms. There are a spread of B–B bond distances ranging from 1.69–1.86 Å. In the third B site, B is bonded in a distorted bent 120 degrees geometry to two O atoms. There is one shorter (1.29 Å) and one longer (1.41 Å) B–O bond length. In the fourth B site, B is bonded in a distorted single-bond geometry to two equivalent B and one H atom. The B–H bond length is 1.21 Å. In the fifth B site, B is bonded in a bent 120 degrees geometry to one B and two O atoms. There is one shorter (1.35 Å) and one longer (1.45 Å) B–O bond length. In the sixth B site, B is bonded in a bent 120 degrees geometry to two O atoms. There is one shorter (1.28 Å) and one longer (1.55 Å) B–O bond length. There are four inequivalent H sites. In the first H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.05 Å) and one longer (1.44 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one B atom. In the third H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. In the fourth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. There are six inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one B and one H atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one K, one B, and one H atom. In the third O site, O is bonded in a trigonal non-coplanar geometry to two B and one H atom. In the fourth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one B atom. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one B, and one H atom. In the sixth O site, O is bonded in a distorted single-bond geometry to two equivalent K and one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B2H10C2NClO3 by Materials Project

((CH3)2NH2)2(B2H2O3)2Cl2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two (ho)bh-o-bh(oh) molecules, two dimethylazanium molecules, and two hydrochloric acid molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

EXAFS investigation of the local structure in URu 2-x Fe x Si 2 : Evidence for distortions below 100 K

X-ray absorption measurements at the U L III , Ru K , and Fe K edges are reported for the hidden order (HO) material URu 2 - x Fe x Si 2 ( x = 0 , 0.05, 0.08, 0.10, 0.12, 0.15, and 0.20) as a function of x and temperature T . Furthermore, when Fe is substituted for Ru, the local structure about Fe shrinks slightly and the first neighbor Fe-Si bond length decreases by ≈ 0.05 Å . More importantly excess disorder is observed below 80–100 K (the coherence temperature T * ) in plots of the Debye-Waller factor σ 2 ( σ is the width of the pair distribution function); at low T the data deviate from the usual Einstein or correlated-Debye model plots. This excess disorder is most prominent for the Ru-Si bond, and σ 2 actually increases below 80 K. These results suggest a local orthorhombic distortion with B 1 g -like symmetry that develops below 80–100 K. A model that describes these local distortions is presented, and discussed in terms of other measurements that indicate a breaking of fourfold symmetry at low T . In addition, the square root of the difference between σ 2 ( T ) for the Ru-Si pair and a Debye fit to these data serves as an order parameter for this orthorhombic distortion, in the temperature range below 100 K. This quantity is a length related to a - b , the difference between the a and b lattice constants in the orthorhombic phase, and provides a connection between this distortion and T * . X-ray absorption near edge structure (XANES) measurements also show that there are no changes in the edge positions down to 0.1 eV for any edge as a function of x , for T in the HO regime.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on NaB(HO)4 by Materials Project

NaB(OH)4 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two NaB(OH)4 sheets oriented in the (0, 1, 0) direction. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.72 Å. B3+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of B–O bond distances ranging from 1.48–1.50 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Na1+, one B3+, and one H1+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one B3+, and one H1+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one B3+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+, one B3+, and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

High-Throughput Screening for Boride Superconductors

A high-throughput screening using density functional calculations is performed to search for stable boride superconductors from the existing materials database. The workflow employs the fast frozen-phonon method as the descriptor to evaluate the superconducting properties quickly. Twenty-three stable candidates were identified during the screening. The superconductivity was obtained earlier experimentally or computationally for almost all found binary compounds. Previous studies on ternary borides are very limited. Here our extensive search among ternary systems confirmed superconductivity in known systems and found several new compounds. Among these discovered superconducting ternary borides, TaMo 2 B 2 shows the highest superconducting temperature of ∼12 K. Most predicted compounds were synthesized previously; therefore, our predictions can be examined experimentally. Our work also demonstrates that the boride systems can have diverse structural motifs that lead to superconductivity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Theoretical search for possible Li–Ni–B crystal structures using an adaptive genetic algorithm

The structural diversity of rare-earth and transition metal borides indicates that alkali-transition metal borides (A-T-B) show tremendous promise in exhibiting a variety of crystal structures with different dimensionalities of T-B frameworks. On the other hand, the A-T-B ternary systems are severely underexplored because of the synthetic challenges associated with their preparation. Accurate and efficient computational predictions of low-energy stable and metastable phases can identify the optimal compositions of the hypothetical compounds in the A-T-B systems to guide the synthesis. As such, in this work, we have computationally discovered several new phases in the Li–Ni–B ternary system. The newly discovered LiNiB, Li 2 Ni 3 B, and Li 2 NiB phases expand the existing theoretical database, and the convex-hull surface of Li–Ni–B has been re-constructed. The lowest energy structure of the LiNiB compound has been found by an adaptive genetic algorithm with layered motif, which matches with the experimentally determined structure. According to our electrochemical calculations, LiNiB and another predicted layered Li 2 NiB compounds have great potential as anode materials for lithium batteries. The Li 2 Ni 3 B compound with the space group P4 3 32 was predicted to crystallize in a cubic structure composed of distorted octahedral units of BNi 6 , which is isostructural to two noncentrosymmetric superconductors Li 2 Pd 3 B and Li 2 Pt 3 B. While we were unable to experimentally confirm the Li 2 Ni 3 B compound utilizing the hydride synthetic route, attempts to synthesize this compound by alternate methods remain highly desirable, considering its potential superconducting properties.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Stable Supercapacity of Binder-Free TiO 2 (B) Epitaxial Electrodes for All-Solid-State Nanobatteries

Owing to its pseudocapacitive, unidimensional, rapid ion channels, TiO 2 (B) is a promising material for application to battery electrodes. In this study, we align these channels by epitaxially growing TiO 2 (B) films with the assistance of an isostructural VO 2 (B) template layer. In a liquid electrolyte, binder-free TiO 2 (B) epitaxial electrodes exhibit a supercapacity near the theoretical value of 335 mA h g –1 and an excellent charge–discharge reproducibility for ≥200 cycles, which outperform those of other TiO 2 (B) nanostructures. For the all-solid-state configuration employing the LiPON solid electrolyte, excellent stability persists. Our findings suggest excellent potential for miniaturizing all-solid-state nanobatteries in self-powered integrated circuits.

25 ENERGY STORAGE↗
NASA NTRS1991

Comparison of spectroscopic properties of Tm and Ho in YAG and YLF crystals

The paper compares the cross-relaxation, energy transfer and loss processes in Tm- and Ho-doped YAG and YLF as a function of temperature, Tm concentration, and excitation power. Significant differences in the behavior of Tm and Tm,Ho in YAG and YLF crystals were found. The cross-relaxation rates of Tm(6 pct) are faster in YLF (about 5 microsec) than YAG (about 10 microsec). The energy transfer rates between Tm and Ho are faster in YLF than YAG. The time it takes for the maximum intensity of 1.7-micron emission to drop 10 percent is 25 microsec for YLF:Tm(6 pct),Ho(0.6 pct) and 65 microsec YAG:Tm(6 pct),Ho(0.5 pct). The losses occurring with increasing pump power for 2.1-micron emission of the above samples are 30 percent less in YLF than YAG. These qualitative differences point to YLF as a valuable 2-micron laser host material.

Armagan, G.↗
DOE OSTI2020

Materials Data on Ho2Cu(BO2)8 by Materials Project

Ho2Cu(BO2)8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.28–2.47 Å. Cu2+ is bonded in an octahedral geometry to six O2- atoms. There are four shorter (1.99 Å) and two longer (2.44 Å) Cu–O bond lengths. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. In the second B3+ site, B3+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.47 Å) and two longer (1.48 Å) B–O bond length. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.35 Å) and two longer (1.40 Å) B–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ho3+ and one B3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Cu2+, and one B3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two B3+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ho3+ and two B3+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu2+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3Ho(BO3)3 by Materials Project

Ba3Ho(BO3)3 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–2.96 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.68–2.99 Å. In the third Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are six shorter (2.80 Å) and three longer (3.05 Å) Ba–O bond lengths. In the fourth Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are six shorter (2.81 Å) and three longer (2.95 Å) Ba–O bond lengths. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in an octahedral geometry to six O2- atoms. There are three shorter (2.23 Å) and three longer (2.28 Å) Ho–O bond lengths. In the second Ho3+ site, Ho3+ is bonded in an octahedral geometry to six O2- atoms. All Ho–O bond lengths are 2.25 Å. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.39 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.39 Å) and one longer (1.40 Å) B–O bond length. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.40 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one B3+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ho3+, and one B3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ho3+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+, one Ho3+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ba2+, one Ho3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one B3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaB(H4O3)2 by Materials Project

NaB(HO)6H2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of two hydrogen molecules and one NaB(HO)6 ribbon oriented in the (1, 0, 0) direction. In the NaB(HO)6 ribbon, Na1+ is bonded to six O2- atoms to form edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.38–2.58 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.33–1.42 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the fourth H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, one B3+, and one H1+ atom. In the second O2- site, O2- is bonded in a water-like geometry to one B3+ and one H1+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Na1+, one B3+, and one H1+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Crystal structures and comparisons of potassium rare-earth molybdates KRE(MoO 4 ) 2 (RE = Tb, Dy, Ho, Er, Yb, and Lu)

Six potassium rare-earth molybdates KRE(MoO 4 ) 2 (RE = Tb, Dy, Ho, Er, Yb, and Lu) were synthesized by flux-assisted growth in K 2 Mo 3 O 10 . The crystal structures were determined using single-crystal X-ray diffraction data. The synthesized molybdates crystallize with the orthorhombic Pbcn space group (No. 60). Trendlines for unit-cell parameters were calculated using data from the current study. The unit-cell parameters a and c increase linearly whereas b decreases with larger RE cations, based on crystal radii. The unit-cell volumes increase linearly and the densities decrease linearly with larger RE cations. The average distances between the RE cations and the nearest O atoms increase with larger cations whereas the average distances of Mo—O and K—O do not show specific trends.

36 MATERIALS SCIENCE↗