Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Rb(CO)2”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Rb(CO)2 by Materials Project

Rb(CO)2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of two Rb(CO)2 sheets oriented in the (1, 0, 0) direction. Rb is bonded in a 6-coordinate geometry to six equivalent O atoms. There are a spread of Rb–O bond distances ranging from 2.90–3.06 Å. C is bonded in a distorted single-bond geometry to one O atom. The C–O bond length is 1.27 Å. O is bonded in a distorted single-bond geometry to three equivalent Rb and one C atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Frustrated magnetism in the layered triangular lattice materials K 2 Co(SeO 3 ) 2 and Rb 2 Co(SeO 3 ) 2

A study of the layered triangular lattice materials K 2 Co(SeO 3 ) 2 and Rb 2 Co(SeO 3 ) 2 is reported here. These isostructural compounds crystallize in the trigonal space group R-3m (No. 166). The magnetic Co 2+ ions form a spin-1/2 triangular lattice and display strongly frustrated magnetism. We find no evidence in the susceptibility or heat capacity for in-plane ordering of the spins; rather the in-plane inverse susceptibility is typical of that seen for frustrated magnets. At around 10 K, a ferromagnetic component appears in the magnetic susceptibility perpendicular to the triangular planes. The heat capacity at low applied fields does not show sharp features, but in larger applied fields a sharp ferromagneticlike transition appears. Field- and direction-dependent magnetization measurements at 2 K indicate that both materials have a magnetic easy axis perpendicular to the triangular planes. The magnetic properties are sensitive to the field applied perpendicular to the triangular planes, which induces a metamagnetization transition at 0.75 T. Spin polarization develops along with the increasing out-of-plane field, resulting in a saturated ferromagnetic state at high fields. In contrast, the magnetic properties are resistant to the in-plane field. Our results suggest that these materials are embodiments of Ising spins on triangular lattices with easy-axis anisotropy.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Salt-Assisted 2H-to-1T' Phase Transformation of Transition Metal Dichalcogenides [plus supplemental information]

Phase engineering of nanomaterials (PEN) has demonstrated great potential in the fields of catalysis, electronics, energy storage and conversion, and condensed matter physics. Recently, transition metal dichalcogenides (TMDs) with unconventional metastable phases (e.g., 1T and 1T') have attracted increasing research interest due to their unique and appealing physicochemical properties. However, there is still a lack of a simple, universal, and controlled method for the preparation of large-scale and high-purity unconventional-phase TMD crystals, restricting their further fundamental study and practical applications. Here, a facile, one-step salt-assisted general strategy is reported for the controlled phase transformation of commercially available TMDs with conventional 2H phase, yielding a large amount of metastable 1T'-phase TMDs, including WS 2 , WSe 2 , MoS 2 , and MoSe 2 . It is found that the easily accessible metal salts, such as K 2 C 2 O 4 ·H 2 O, K 2 CO 3 , Na 2 CO 3 , Rb 2 CO 3 , Cs 2 CO 3 , KHCO 3 , NaHCO 3 , and NaC 2 O 4 , can be used to assist the 2H-to-1T' phase transformation, greatly simplifying the synthetic process for producing metastable 1T'-TMDs. Importantly, this method can also be used to prepare 1T'-TMD alloys, such as 1T'-WS 2x Se 2(1–x) . We report this newly developed strategy is robust and highly effective, which can also be used for the phase engineering of other materials with various polymorphs.

1T′ phase↗
DOE OSTI2024

Efficient crystal structure materials as reactive sorbent for the CO 2 and CH 4 adsorption and storage

The efficient dirubidium cobalt bis(dihydrogendiphosphate) dihydrate compound is successfully synthesized in a solution and used as a reactive sorbent for the CO 2 and CH 4 gases adsorption and storage. A crystal of this Rb 2 Co(H 2 P 2 O 7 ) 2 ·2H 2 O compound has been isolated and characterized by single X-ray diffraction analysis and was found to crystallize in the triclinic system (P$\overline{1}$) with the cell parameters (Å): 6.980(1), 7.370(1), 7.816(1), 81.74(1), 70.35(1), 86.34(1); V = 374.68(9) Å3, Z = 2. The crystal-packing consists of a three-dimensional framework made upon corners and edges sharing of [RbO 7 ], [H 2 P 2 O 7 ] and [CoO 6 ] entities, furthermore linked by a network of H-bonds. The UV–Vis spectroscopy revealed usual transitions between the ground state 4T1g and the upper levels 4T2g, 4A2g and 4T1g (P). Moreover, the CO 2 and CH 4 gases sorption measurements were successfully performed at two different temperatures (25 and 45 °C) and various pressures ranging from vacuum to 50 bar. Our results show that rate of CO 2 and CH 4 capturing was 3.10 mmol/g and 2.35 mmol/g at temperature 25 °C and pressure 50 bar, respectively. This compound showed a clear potential for CO 2 /CH 4 adsorption and storage thereby paving the way towards its exploration and adaptation for capturing and collecting carbon dioxide and greenhouse gases from the air, and their conversion into hydrocarbon fuels using existing mature technologies. We have also conducted density functional theory calculations to study the CO 2 and CH 4 adsorption properties of Rb 2 Co(H 2 P 2 O 7 ) 2 ·2H 2 O. The simulation results show enhanced adsorption of both types of molecules on the surface of the material.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Single crystal neutron and magnetic measurements of Rb 2 Mn 3 (VO 4 ) 2 CO 3 and K 2 Co 3 (VO 4 ) 2 CO 3 with mixed honeycomb and triangular magnetic lattices

Two new alkali vanadate carbonates with divalent transition metals have been synthesized as large single crystals via a high-temperature (600 °C) hydrothermal technique. Compound I, Rb 2 Mn 3 (VO 4 ) 2 CO 3 , crystallizes in the trigonal crystal system in the space group P[3 with combining macron]1c, and compound II, K 2 Co 3 (VO 4 ) 2 CO 3 , crystallizes in the hexagonal space group P6 3 /m. Both structures contain honeycomb layers and triangular lattices made from edge-sharing MO 6 octahedra and MO 5 trigonal bipyramids, respectively. The honeycomb and triangular layers are connected along the c-axis through tetrahedral [VO 4 ] groups. The MO 5 units are connected with each other by carbonate groups in the ab-plane by forming a triangular magnetic lattice. The difference in space groups between I and II was also investigated with Density Functional Theory (DFT) calculations. Single crystal magnetic characterization of I indicates three magnetic transitions at 77 K, 2.3 K, and 1.5 K. The corresponding magnetic structures for each magnetic transition of I were determined using single crystal neutron diffraction. At 77 K the compound orders in the MnO 6 -honeycomb layer in a Néel-type antiferromagnetic orientation while the MnO 5 triangular lattice ordered below 2.3 K in a colinear ‘up–up–down’ fashion, followed by a planar ‘Y’ type magnetic structure. K 2 Co 3 (VO 4 ) 2 CO 3 (II) exhibits a canted antiferromagnetic ordering below T N = 8 K. Here, the Curie–Weiss fit (200–350 K) gives a Curie–Weiss temperature of –42 K suggesting a dominant antiferromagnetic coupling in the Co 2+ magnetic sublattices.

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

Materials Data on RbMg6Co by Materials Project

RbMg6Co crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Rb is bonded in a 2-coordinate geometry to eight Mg and two equivalent Co atoms. There are a spread of Rb–Mg bond distances ranging from 3.33–4.00 Å. Both Rb–Co bond lengths are 3.71 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a distorted single-bond geometry to two equivalent Rb, two equivalent Mg, and one Co atom. Both Mg–Mg bond lengths are 3.17 Å. The Mg–Co bond length is 2.57 Å. In the second Mg site, Mg is bonded in a 2-coordinate geometry to four equivalent Mg and two equivalent Co atoms. All Mg–Mg bond lengths are 3.09 Å. Both Mg–Co bond lengths are 3.27 Å. In the third Mg site, Mg is bonded in a distorted bent 120 degrees geometry to one Rb, two equivalent Mg, and two equivalent Co atoms. Both Mg–Co bond lengths are 2.68 Å. In the fourth Mg site, Mg is bonded in a 2-coordinate geometry to two equivalent Rb and four equivalent Mg atoms. Co is bonded in a 6-coordinate geometry to two equivalent Rb and eight Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Influence of Cs Loading on Pt/m-ZrO 2 Water–Gas Shift Catalysts

Certain alkali metals (Na, K) at targeted loadings have been shown in recent decades to significantly promote the LT-WGS reaction. This occurs at alkali doping levels where a redshift in the C-H band of formate occurs, indicating electronic weakening of the bond. The C-H bond breaking of formate is the proposed rate-limiting step of the formate associative mechanism, lending support to the occurrence of this mechanism in H2-rich environments of the LT-WGS stage of fuel processors. Continuing in this vein of research, 2%Pt/m-ZrO 2 was promoted with various levels of Cs in order to explore its influence on the rate of formate intermediate decomposition, as well as that of LT-WGS in a fixed bed reactor. In situ DRIFTS experiments revealed that Cs promoter loadings of 3.87% to 7.22% resulted in significant acceleration of the forward formate decomposition in steam at 130 °C. Of all of the alkali metals tested to date, the redshift in the formate ν(CH) band with the incorporation of Cs was the greatest. XANES difference experiments at the Pt L 2 and L 3 edges indicated that the electronic effect was not likely due to an enrichment of electronic density on Pt. CO 2 TPD experiments revealed that, unlike Na and K promoters, Cs behaves more like Rb in that the decomposition of the second intermediate in LT-WGS, carbonate species, is hindered due to (1) increased basicity of Cs, (2) the tendency of Cs to cover Pt sites that facilitate CO 2 decomposition, and (3) the tendency of Cs to increase Pt particle size as shown by EXAFS results, resulting in fewer Pt sites that facilitate CO2 decomposition. As such, the LT-WGS rate was hindered overall and the rate-limiting step shifted to carbonate decomposition (CO 2 removal). Like its Rb counterpart, low levels of added Cs (e.g., 0.72%Cs) were found to improve the stability of the catalyst relative to the unpromoted catalyst; the stability comparison was made at similar CO conversion level as well as similar space velocity.

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

Materials Data on RbMg6Co by Materials Project

RbMg6Co crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Rb is bonded to ten Mg and two equivalent Co atoms to form RbMg10Co2 cuboctahedra that share corners with six equivalent RbMg10Co2 cuboctahedra, edges with four equivalent MgRb2Mg10 cuboctahedra, faces with two equivalent RbMg10Co2 cuboctahedra, and faces with two equivalent MgRb2Mg10 cuboctahedra. There are a spread of Rb–Mg bond distances ranging from 3.21–3.37 Å. Both Rb–Co bond lengths are 3.35 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a distorted single-bond geometry to two equivalent Rb, six Mg, and one Co atom. There are a spread of Mg–Mg bond distances ranging from 3.18–3.28 Å. The Mg–Co bond length is 2.58 Å. In the second Mg site, Mg is bonded in a 2-coordinate geometry to two equivalent Rb, seven Mg, and two equivalent Co atoms. There are a spread of Mg–Mg bond distances ranging from 2.93–3.40 Å. Both Mg–Co bond lengths are 3.03 Å. In the third Mg site, Mg is bonded in a distorted q6 geometry to ten Mg atoms. Both Mg–Mg bond lengths are 3.28 Å. In the fourth Mg site, Mg is bonded to two equivalent Rb and ten Mg atoms to form distorted MgRb2Mg10 cuboctahedra that share corners with six equivalent MgRb2Mg10 cuboctahedra, edges with four equivalent RbMg10Co2 cuboctahedra, faces with two equivalent RbMg10Co2 cuboctahedra, and faces with two equivalent MgRb2Mg10 cuboctahedra. Co is bonded in a 8-coordinate geometry to two equivalent Rb and six Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(YbS2)3 by Materials Project

YbRb(YbS2)2(S)2 crystallizes in the orthorhombic Cmmm space group. The structure is two-dimensional and consists of four hydrogen sulfide molecules; two ytterbium molecules; and one Rb(YbS2)2 sheet oriented in the (0, 0, 1) direction. In the Rb(YbS2)2 sheet, Rb1+ is bonded in a square co-planar geometry to four equivalent S+1.33- atoms. All Rb–S bond lengths are 3.29 Å. Yb+2.33+ is bonded in a linear geometry to two equivalent S+1.33- atoms. Both Yb–S bond lengths are 2.62 Å. S+1.33- is bonded in a 3-coordinate geometry to one Rb1+, one Yb+2.33+, and one S+1.33- atom. The S–S bond length is 2.10 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(CoAs)2 by Materials Project

Rb(CoAs)2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a body-centered cubic geometry to eight equivalent As3- atoms. All Rb–As bond lengths are 3.53 Å. Co+2.50+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing CoAs4 tetrahedra. All Co–As bond lengths are 2.32 Å. As3- is bonded in a 8-coordinate geometry to four equivalent Rb1+ and four equivalent Co+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

First-Principles Calculations of the Structural, Electronic, Optical, and Mechanical Properties of 21 Pyrophosphate Crystals

Pyrophosphate crystals have a wide array of applications in industrial and biomedical fields. However, fundamental understanding of their electronic structure, optical, and mechanical properties is still scattered and incomplete. In the present research, we report a comprehensive theoretical investigation of 21 pyrophosphates A 2 M (H 2 P 2 O 7 ) 2 •2H 2 O with either triclinic or orthorhombic crystal structure. The molecule H 2 P 2 O 7 is the dominant molecular unit, whereas A = (K, Rb, NH 4 , Tl), M = (Zn, Cu, Mg, Ni, Co, Mn), and H 2 O stand for the cation elements, transition metals, and the water molecules, respectively. The electronic structure, interatomic bonding, partial charge distribution, optical properties, and mechanical properties are investigated by first-principles calculations based on density functional theory (DFT). Most of these 21 crystals are theoretically investigated for the first time. The calculated results show a complex interplay between A, M, H 2 P 2 O 7 , and H 2 O, resulting in either metallic, half-metallic, or semi-conducting characteristics. The novel concept of total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals to correlate with the calculated properties, especially the mechanical properties. This work provides a large database for pyrophosphate crystals and a road map for potential applications of a wider variety of phosphates.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(CoP)2 by Materials Project

Rb(CoP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a distorted body-centered cubic geometry to eight equivalent P3- atoms. All Rb–P bond lengths are 3.48 Å. Co+2.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing CoP4 tetrahedra. All Co–P bond lengths are 2.20 Å. P3- is bonded in a 8-coordinate geometry to four equivalent Rb1+ and four equivalent Co+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(CoS)2 by Materials Project

Rb(CoS)2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a body-centered cubic geometry to eight equivalent S2- atoms. All Rb–S bond lengths are 3.41 Å. Co+1.50+ is bonded to four equivalent S2- atoms to form a mixture of edge and corner-sharing CoS4 tetrahedra. All Co–S bond lengths are 2.22 Å. S2- is bonded in a 8-coordinate geometry to four equivalent Rb1+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(CoSe)2 by Materials Project

Rb(CoSe)2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb1+ is bonded in a body-centered cubic geometry to eight equivalent Se2- atoms. All Rb–Se bond lengths are 3.52 Å. Co+1.50+ is bonded to four equivalent Se2- atoms to form a mixture of edge and corner-sharing CoSe4 tetrahedra. All Co–Se bond lengths are 2.36 Å. Se2- is bonded in a 8-coordinate geometry to four equivalent Rb1+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2La10Co2I17 by Materials Project

Rb2La10Co2I17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Rb is bonded in a 2-coordinate geometry to four I atoms. There are two shorter (4.18 Å) and two longer (4.30 Å) Rb–I bond lengths. There are four inequivalent La sites. In the first La site, La is bonded to one Co and five I atoms to form a mixture of edge and corner-sharing LaCoI5 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. The La–Co bond length is 2.90 Å. There are a spread of La–I bond distances ranging from 3.20–3.47 Å. In the second La site, La is bonded to one Co and five I atoms to form distorted LaCoI5 octahedra that share corners with five LaCo2I4 octahedra and edges with five LaCoI5 octahedra. The corner-sharing octahedra tilt angles range from 9–11°. The La–Co bond length is 2.76 Å. There are a spread of La–I bond distances ranging from 3.24–3.49 Å. In the third La site, La is bonded to two equivalent Co and four I atoms to form a mixture of distorted edge and corner-sharing LaCo2I4 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (2.75 Å) and one longer (2.95 Å) La–Co bond lengths. There are a spread of La–I bond distances ranging from 3.40–3.59 Å. In the fourth La site, La is bonded to one Co and five I atoms to form a mixture of distorted edge and corner-sharing LaCoI5 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. The La–Co bond length is 2.63 Å. There are a spread of La–I bond distances ranging from 3.26–3.49 Å. Co is bonded to six La atoms to form edge-sharing CoLa6 octahedra. There are six inequivalent I sites. In the first I site, I is bonded in a distorted T-shaped geometry to three La atoms. In the second I site, I is bonded in a distorted T-shaped geometry to three La atoms. In the third I site, I is bonded in a 4-coordinate geometry to one Rb and three La atoms. In the fourth I site, I is bonded in a distorted T-shaped geometry to three La atoms. In the fifth I site, I is bonded in a distorted square co-planar geometry to four La atoms. In the sixth I site, I is bonded in a 2-coordinate geometry to one Rb and two La atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2Co(SO7)2 by Materials Project

Rb2Co(SO7)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Rb is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Rb–O bond distances ranging from 2.86–3.34 Å. Co is bonded in an octahedral geometry to six O atoms. There is four shorter (1.78 Å) and two longer (1.79 Å) Co–O bond length. S is bonded in a tetrahedral geometry to four O atoms. There are a spread of S–O bond distances ranging from 1.48–1.50 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two equivalent Rb and one S atom. In the second O site, O is bonded in a distorted single-bond geometry to one Rb and one S atom. In the third O site, O is bonded in a single-bond geometry to two equivalent Rb and one S atom. In the fourth O site, O is bonded in a single-bond geometry to one Rb and one Co atom. In the fifth O site, O is bonded in a distorted single-bond geometry to one Rb and one S atom. In the sixth O site, O is bonded in a distorted single-bond geometry to one Rb and one Co atom. In the seventh O site, O is bonded in a single-bond geometry to one Co atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbNa7(CoO3)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗