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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Spectroscopic characterization of Mn 2+ and Cd 2+ coordination to phosphorothioates in the conserved A9 metal site of the hammerhead ribozyme

Phosphorothioate modifications have widespread use in the field of nucleic acids. As substitution of sulfur for oxygen can alter metal coordination preferences, the phosphorothioate metal-rescue experiment is a powerful method for identifying metal coordination sites that influence specific properties in a large RNAs. The A9/G10.1 metal binding site of the hammerhead ribozyme (HHRz) has previously been shown to be functionally important through phosphorothioate rescue experiments. While an A9-S Rp substitution is inhibitory in Mg 2+ , thiophilic Cd 2+ rescues HHRz activity. Mn 2+ is also often used in phosphorothioate metal-rescue studies but does not support activity for the A9-S Rp HHRz. Here, we use EPR, electron spin-echo envelope modulation (ESEEM), and X-ray absorption spectroscopic methods to directly probe the structural consequences of Mn 2+ and Cd 2+ coordination to R p and S p phosphorothioate modifications at the A9/G10.1 site in the truncated hammerhead ribozyme (tHHRz). The results demonstrate that while Cd 2+ does indeed bind to S in the thio-substituted ligand, Mn 2+ coordinates to the non–sulfur oxo group of this phosphorothioate, regardless of isomer. Computational models demonstrate the energetic preference of Mn—O over Mn—S coordination in metal-dimethylthiophosphate models. In the case of the tHHRz, the resulting Mn 2+ coordination preference of oxygen in either R p or S p A9 phosphorothioates differentially tunes catalytic activity, with Mn—O coordination in the A9-S Rp phosphorothioate enzyme being inhibitory.

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

Magnetic properties of ferrimagnetic Mn 3 Si 2 Se 6

The physical properties of Mn 3 Si 2 Se 6 have been investigated using single crystals grown by iodine-assisted vapor transport. Additionally, the material possesses a ferrimagnetic ground state and the properties are similar to those in the isostructural compound Mn 3 Si 2 Se 6 . Furthermore, in these trigonal materials, the dominant magnetic exchanges are antiferromagnetic and intrinsically frustrated, leading to a variety of competing ground states. In Mn 3 Si 2 Se 6 , the Curie temperature is TC = 67(1)K, which is slightly lower than that of Mn 3 Si 2 Se 6 where TC = 78K. The anisotropy field is also smaller in the selenide relative to the telluride. In both materials, short-range correlations likely exist well-above TC. Neutron single crystal diffraction data on Mn 3 Si 2 Se 6 suggest a collinear ferrimagnetic structure with the moments tilting out of the ab-plane in zero-field. Finally, the magnetization of vapor grown Mn 3 Si 2 Se 6 is shown for comparison; these vapor grown crystals do not show a sharp onset of magnetic anisotropy above 300K as was previously observed for melt grown Mn 3 Si 2 Se 6 crystals.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Electronic, structural and magnetic properties of Mn (1+x) Pt (1-x) Sb

Electronic and magnetic properties of half-metallic Heusler alloys can be modified by tuning their chemical compositions. We have carried out a combined theoretical and experimental investigation of Mn (1+x) Pt (1-x) Sb (0 ≤ x ≤ 0.5) alloys. Our first-principles calculations indicate that the stoichiometric MnPtSb exhibits nearly half-metallic band structure, but a robust half-metallicity can be achieved in Mn-rich compositions Mn (1+x) Pt (1-x) Sb (0 ≤ x ≤ 0.5) with x = 0.25 and higher in their cubic structures. In addition, while MnPtSb exhibits ferromagnetic alignment, Mn (1+x) Pt (1-x) Sb are ferrimagnetic for all non-zero values of x. We have also synthesized cubic MnPtSb and Mn 1.25 Pt 0.75 Sb alloys using arc melting and annealing. The magnetic properties of these alloys are consistent with our theoretical predictions. Furthermore, these results indicate that the Mn-rich Mn (1+x) Pt (1-x) Sb alloys have potential for spin-transport-based devices.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Distribution of Mn Oxidation States in Grassland Soils and Their Relationships with Soil Pores

Manganese (Mn) is known to be an active contributor to processing and cycling of soil organic carbon (C), yet the exact mechanisms behind its interactions with C are poorly understood. Plant diversity in terrestrial ecosystems drives feedback links between plant C inputs and soil pores, where the latter, in turn, impact the redox environment and Mn. This study examined associations between soil pores (>36 μm Ø) and Mn within intact soils from two grassland ecosystems, after their >6-year implementation in a replicated field experiment. In this work, we used μ-XRF imaging and XANES spectroscopy to explore spatial distribution patterns of Mn oxidation states, combined with X-ray computed microtomography and 2D zymography. A high plant diversity system (restored prairie) increased soil C and modified spatial distribution patterns of soil pores as compared to a single species system (monoculture switchgrass). In switchgrass, the abundance of oxidized and reduced Mn oxidation states varied with distance from pores consistently with anticipated O 2 diffusion, while in the soil from restored prairie, the spatial patterns suggested that biological activity played a greater role in influencing Mn distributions. Based on the findings, we propose a hypothesis that Mn transformations promote C gains in soils of high plant diversity grasslands.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Tuning the Morphology and Electronic Properties of Single-Crystal LiNi 0.5 Mn 1.5 O 4-δ : Exploring the Influence of LiCl–KCl Molten Salt Flux Composition and Synthesis Temperature

Single-crystal materials have played a unique role in the development of high-performance cathode materials for Li batteries due to their favorable chemomechanical stability. The molten salt synthesis method has become one of the most prominent techniques used to synthesize single-crystal layered and spinel materials. In this work, the molten salt synthesis method is used as a technique to tune both the morphology and Mn 3+ content of high-voltage LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes. The resulting materials are thoroughly characterized by a suite of analytical techniques, including synchrotron X-ray core-level spectroscopy, which are sensitive to the material properties on multiple length scales. Furthermore, the multidimensional characterization allows us to build a materials library according to the molten salt phase diagram as well as to establish the relationship among synthesis, material properties, and battery performance. The results of this work show that the Mn 3+ content is primarily dependent on the synthesis temperature and increases as the temperature is increased. Additionally, the particle morphology is mostly dependent on the composition of the molten salt flux, which can be tailored to obtain well-defined octahedrons enclosed by (111) facets, plates with predominant ($11\tilde{2}$) facets, irregularly shaped particles, or mixtures of these. The electrochemical measurements indicate that the Mn 3+ content has a larger contribution to the battery performance of LNMO than do morphological characteristics and that a significant amount of Mn 3+ could become detrimental to the battery performance. However, with similar Mn 3+ contents, morphology still plays a role in influencing the battery cycle life and rate performance. The insights of molten salt synthesis parameters on the formation of LNMO, with deconvolution of the roles of Mn 3+ and morphology, are crucial to continuing studies in the rational design of LNMO cathode materials for high-energy Li batteries.

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

Independent Mutation of Two Bridging Carboxylate Ligands Stabilizes Alternate Conformers of the Photosynthetic O 2 -Evolving Mn 4 CaO 5 Cluster in Photosystem II

The O 2 -evolving Mn 4 CaO 5 cluster in Photosystem II is ligated by six carboxylate residues. One of these is D170 of the D1 subunit. This carboxylate bridges between one Mn ion (Mn4) and the Ca ion. A second carboxylate ligand is D342 of the D1 subunit. This carboxylate bridges between two Mn ions (Mn1 and Mn2). D170 and D342 are located on opposite sides of the Mn 4 CaO 5 cluster. Recently, it was shown that the D170E mutation perturbs both the intricate networks of H-bonds that surround the Mn 4 CaO 5 cluster and the equilibrium between different conformers of the cluster in two of its lower oxidation states, S 1 and S 2 , while still supporting O 2 evolution at approx. 50% the rate of wild-type. In this study, we show that the D342E mutation produces much the same alterations to the cluster’s FTIR and EPR spectra as D170E, while still supporting O 2 evolution at approx. 20% the rate of wild-type. Furthermore, the double mutation, D170E + D342E, behaves similarly to the two single mutations. We conclude that D342E alters the equilibrium between different conformers of the cluster in its S 1 and S 2 states in the same manner as D170E and perturbs the H-bond networks in a similar fashion. This is the second identification of a Mn 4 CaO 5 metal ligand whose mutation influences the equilibrium between the different conformers of the S 1 and S 2 states without eliminating O 2 evolution. Finally, this finding has implications for our understanding of the mechanism of O 2 formation in terms of catalytically active/inactive conformations of the Mn 4 CaO 5 cluster in its lower oxidation states.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Transition Metal Dissolution Mechanisms and Impacts on Electronic Conductivity in Composite LiNi 0.5 Mn 1.5 O 4 Cathode Films

The high-voltage LiNi 0.5 Mn 1.5 O 4 (LNMO) spinel cathode material offers high energy density storage capabilities without the use of costly Co that is prevalent in other Li-ion battery chemistries (e.g., LiNi x Mn y Co z O 2 (NMC)). Unfortunately, LNMO-containing batteries suffer from poor cycling performance because of the intrinsically coupled processes of electrolyte oxidation and transition metal dissolution that occurs at high voltage. In this work, we use operando electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies to demonstrate that transition metal dissolution in LNMO is tightly coupled to HF formation (and thus, electrolyte oxidation reactions as detected with operando and in situ solution NMR), indicative of an acid-driven disproportionation reaction that occurs during delithiation (i.e., battery charging). Leveraging the temporal resolution (s-min) of magnetic resonance, we find that the LNMO particles accelerate the rate of LiPF 6 decomposition and subsequent Mn 2+ dissolution, possibly due to the acidic nature of terminal Mn-OH groups. X-ray photoemission electron microscopy (XPEEM) provides surface-sensitive and localized X-ray absorption spectroscopy (XAS) measurements, in addition to X-ray photoelectron spectroscopy (XPS), that indicate disproportionation is enabled by surface reconstruction upon charging, which leads to surface Mn 3+ sites on the LNMO particle surface that can disproportionate into Mn 2+ (dissolved) and Mn 4+ (s) . During discharge of the battery, we observe high quantities of metal fluorides (in particular, MnF 2 ) in the cathode electrolyte interphase (CEI) on LNMO as well as the conductive carbon additives in the composite. Electronic conductivity measurements indicate that the MnF 2 decreases film conductivity by threefold compared to LiF, suggesting that this CEI component may impede both the ionic and electronic properties of the cathode. Ultimately, to prevent transition metal dissolution and the associated side reactions in spinel-type cathodes (particularly those that operate at high voltages like LNMO), the use of electrolytes that offer improved anodic stability and prevent acid byproducts will likely be necessary.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Anomalous transport due to Weyl fermions in the chiral antiferromagnets Mn 3 X, X = Sn, Ge

The recent discoveries of strikingly large zero-field Hall and Nernst effects in antiferromagnets Mn 3 X(X = Sn, Ge) have brought the study of magnetic topological states to the forefront of condensed matter research and technological innovation. These effects are considered fingerprints of Weyl nodes residing near the Fermi energy, promoting Mn 3 X(X = Sn, Ge) as a fascinating platform to explore the elusive magnetic Weyl fermions. In this review, we provide recent updates on the insights drawn from experimental and theoretical studies of Mn 3 X(X = Sn, Ge) by combining previous reports with our new, comprehensive set of transport measurements of high-quality Mn 3 Sn and Mn 3 Ge single crystals. In particular, we report magnetotransport signatures specific to chiral anomalies in Mn 3 Ge and planar Hall effect in Mn 3 Sn, which have not yet been found in earlier studies. The results summarized here indicate the essential role of magnetic Weyl fermions in producing the large transverse responses in the absence of magnetization.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

The striking influence of oxophilicity differences in heterometallic Mo–Mn oxide cluster reactions with water

Mixed-metal oxides have proven to be effective catalysts for the hydrogen evolution reaction, often outperforming either of the binary metal oxides. The reactivity of Mn x MoO y - (x = 1, 2; y = 3, 4) clusters toward H 2 O was investigated via time-of-flight mass spectrometry with clear evidence of cluster oxidation and corresponding H 2 production, specifically for Mn x MoO 3 - (x = 1, 2) clusters. Unlike previously studied MoxOy- clusters, which assumed a broad distribution of stoichiometries (typically x ≤ y ≤ 3x), both MnMoOy- and Mn 2 MoO y - preferentially formed y = 3 and 4 compositions in significant quantities under our source conditions. The electronic and molecular structures of the Mn x MoO y (x = 1, 2; y = 3, 4) anion and neutral clusters were probed with anion photoelectron spectroscopy and analyzed with supporting density functional theory calculations. Our studies suggest that both metal centers are involved in initial cluster–water complex formation, while Mo is the center that undergoes oxidation; hence, reactivity terminates when Mo is saturated in its highest oxidation state of +6. Across these four clusters, Mn remains relatively reduced and is stable in a high-spin electronic configuration. The preferential reactivity of water molecules toward the Mo center rather than Mn is rationalized by the much lower relative oxophilicity of Mn.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

First-principles insight into all-optical spin switching in the half-metallic Heusler ferrimagnet Mn 2 RuGa

All-optical spin switching (AOS) represents a new frontier in magnetic storage technology—spin manipulation without a magnetic field—but its underlying working principle is not well understood. Many AOS ferrimagnets such as GdFeCo are amorphous and renders the high-level first-principles study unfeasible. The crystalline half-metallic Heusler Mn 2 RuGa presents an opportunity. Here we carry out hitherto the comprehensive density functional investigation into the material properties of Mn 2 RuGa, and introduce two concepts—the spin anchor site and the optical active site—as two pillars for AOS in ferrimagnets. In Mn 2 RuGa, Mn(4a) serves as the spin anchor site, whose band is below the Fermi level and has a strong spin moment, while Mn(4c) is the optical active site whose band crosses the Fermi level. Our magneto-optical Kerr spectrum and band structure calculation jointly reveal that the delicate competition between the Ru-4d and Ga-4p states is responsible for the creation of these two sites. Furthermore these two sites found here not only present a unified picture for both Mn 2 RuGa and GdFeCo, but also open the door for future applications. Specifically, we propose a Mn 2 Ru x Ga-based magnetic tunnel junction where a single laser pulse can control magnetoresistance.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Optimized in situ crystal growth and disordered quasi-one-dimensional magnetism in Li 2 Mn 2 ( MoO 4 ) 3

We present that the quasi-one-dimensional structure of Li 2 Mn 2 ( MoO 4 ) 3 consists of three mutually distinct chains of Li 1 - x Mn x -centered polyhedra in which Mn ostensibly adopts a J = 5 / 2 Mn 2 + configuration. In situ x-ray scattering experiments carried out as crystallites emerge from a molten oxide solution facilitate the synthesis of large single crystals. Ex situ x-ray diffraction finds no evidence of long-range Li/Mn occupancy ordering, suggesting that the structure is effectively composed of finite chains of Mn moments of statistically varying lengths. UV/visible diffuse reflectance spectroscopy measurements establish a wide 3.43(12)-eV direct charge gap consistent with the local polyhedral coordination of the nominally Mn 2 + species. The temperature T dependence of the DC magnetic susceptibility χ reveals a fluctuating moment of only 2.74 μ B ± 0.01 μ B /Mn, dramatically reduced from the 5.9 μ B /Mn expected for Mn 2 + . Meanwhile, the Weiss temperature Θ W = - 89 ± 1 K reveals antiferromagnetic fluctuations that are stymied from reaching an ordered state apparently by the chemical disorder intrinsic to the polyhedral chains. Measurements of magnetization vs field H at T ≤ 10 K are far from saturation even at H = 5 T and are strongly non-Brillouin-like, instead scaling as H / T 0.24 ( 3 ) and suggesting the presence of quantum fluctuations associated with an eventual quasi-one-dimensional, disordered magnetic phase.

1-dimensional systems↗
DOE OSTI2020

Large anomalous Nernst and inverse spin-Hall effects in epitaxial thin films of kagome semimetal Mn 3 Ge

Synthesis of crystallographically well-defined thin films of topological materials is important for unraveling their mesoscale quantum properties and for device applications. Mn 3 Ge , an antiferromagnetic Weyl semimetal with a chiral magnetic structure on a kagome lattice, is expected to have enhanced Berry curvature around Weyl nodes near the Fermi energy, leading to large anomalous Hall/Nernst effects and a large spin-Hall effect. Using magnetron sputtering, we have grown epitaxial thin films of hexagonal D 0 19 Mn 3 Ge that are flat and continuous. Large anomalous Nernst and inverse spin-Hall effects are observed in thermoelectric and spin-pumping devices. The anomalous Nernst signal in our Mn 3 Ge films is estimated to be 0.1 μV/K and is comparable to that in ferromagnetic Fe, despite Mn 3 Ge having a weak magnetization of ~ 3.5 m μ B / Mn at room temperature. In this work, the spin-mixing conductance is 90.5 nm – 2 at the Py / Mn 3 Ge interface, and the spin-Hall angle in Mn 3 Ge is estimated to be about eight times of that in Pt.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Durable Mn-Based PGM-Free Catalysts for Polymer Electrolyte Membrane Fuel Cells

This proposed project aims to develop and evaluate novel manganese based, nitrogen-derived, PGM-free electrocatalysts (denoted as Mn-N-C) to fully address the membrane electrolyte assemblies (MEA)’s ionomer degradation issue resulting from iron. Four thrusts will be pursed in this proposed project. First, advanced first-principles computation methods will be employed to accelerate the rational catalyst design and synthesis. Second, an effective hydro-gel method will be used to maximize atomic Mn active sites embedded in carbon matrix. Next, state-of-the art methods in fuel cell companies will be used to fabricate MEAs containing the Mn-N-C catalysts. Finally, industry standards will be rigorously followed to evaluate fuel cell performance and durability of the Mn-N-C catalysts. With successful completion of the project, it is expected that the following outcomes will be achieved. (1) A set of MEAs containing the Mn-N-C catalysts and with active area large than 50 cm 2 for independent testing, (2) testing results demonstrating that the MEAs of Mn-N-C catalysts have mass activity of 0.044 A/cm 2 at 0.9 VIR-free and H 2 /air performance of 0.50 V at 1.0 A/cm 2 ; (3) fundamental understanding of the composition-structure-property relation of the PGM-free Mn- N-C catalysts, and (4) computational data, measurement data, and publications deposited into the database of ElectroCat Consortium.

08 HYDROGEN↗
DOE OSTI2024

Characterization of Mn 5 Ge 3 Contacts on a Shallow Ge/SiGe Heterostructure

Mn 5 Ge 3 is a ferromagnetic phase of the Mn-Ge system that is a potential contact material for efficient spin injection and detection. Here, we investigate the creation of Mn 5 Ge 3 -based contacts on a Ge/SiGe quantum well heterostructure via solid-state synthesis. X-ray diffraction spectra fitting indicates the formation of Mn 5 Ge 3 -based contacts on bulk Ge and Ge/SiGe. High-resolution scanning transmission electron microscopy imaging and energy dispersive X-ray spectroscopy verify the correct Mn 5 Ge 3 -based phase formation. Schottky diode measurements, transmission line measurements, and Hall measurements reveal that Mn 5 Ge 3 -based contacts serve as good p-type contacts for Ge/SiGe quantum well heterostructures due to having a low Schottky barrier height of 0.10 eV (extracted from a Mn 5 Ge 3 /n-Ge analogue) and a contact resistance in the order of 1 kΩ. Furthermore, we show that these electrical characteristics have a gate-voltage dependence, thereby providing tunability.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Microstructural Engineering of Mn-Alloyed Austenitic Steel for Hydrogen Storage and Delivery

Austenitic stainless steels are commonly used for hydrogen storage and transportation. These alloys have a high nickel (Ni) content, which increases alloy cost. In this study, high manganese (Mn) austenitic alloys were evaluated as potential lower cost alternatives. Two heats of high Mn alloys with different stacking fault energies (SFE) of ~29 mJ·m -2 and 49 mJ·m -2 were acquired. Additionally, a new vanadium (V)-microalloyed high Mn alloy was designed to achieve a SFE of 47 mJ·m -2 to minimize planar slip deformation mechanisms. Post-processing via cold working in conjunction with aging was also performed on the V-microalloyed high Mn steel. Hydrogen embrittlement sensitivity was investigated using circumferential notch tensile specimens cathodically charged with hydrogen in a 0.05M NaOH electrolytic solution. The alloys were compared to a cold-worked 316L stainless steel, which exhibited no strength loss due to hydrogen. The high Mn alloys with SFE of ~29 mJ·m 2 and 49 mJ·m -2 had notch strength losses of 11 and 6 pct, respectively. The V-microalloyed high Mn steel in the as-hot-rolled condition had a notch strength loss of 17 pct. Furthermore, the V-microalloyed high Mn steel in the cold worked and aged condition indicated no notch strength loss in hydrogen, which was comparable to the performance of the 316L stainless steel.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(GaS2)2 by Materials Project

MnGa2S4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with ten GaS4 tetrahedra and edges with three MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.55–2.66 Å. In the second Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with eight GaS4 tetrahedra and edges with five MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.54–2.74 Å. In the third Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with ten GaS4 tetrahedra and edges with three MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.56–2.67 Å. In the fourth Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with six GaS4 tetrahedra and edges with six MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.54–2.61 Å. In the fifth Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with six GaS4 tetrahedra and edges with six MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.51–2.62 Å. In the sixth Mn2+ site, Mn2+ is bonded to six S2- atoms to form MnS6 octahedra that share corners with eight GaS4 tetrahedra and edges with five MnS6 octahedra. There are a spread of Mn–S bond distances ranging from 2.54–2.72 Å. There are twelve inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three MnS6 octahedra and corners with six GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Ga–S bond distances ranging from 2.22–2.36 Å. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with four MnS6 octahedra and corners with five GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Ga–S bond distances ranging from 2.26–2.38 Å. In the third Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with four MnS6 octahedra and corners with five GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Ga–S bond distances ranging from 2.26–2.38 Å. In the fourth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three MnS6 octahedra and corners with six GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Ga–S bond distances ranging from 2.22–2.36 Å. In the fifth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with five MnS6 octahedra, corners with three GaS4 tetrahedra, and an edgeedge with one GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Ga–S bond distances ranging from 2.25–2.34 Å. In the sixth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three MnS6 octahedra and corners with six GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Ga–S bond distances ranging from 2.22–2.36 Å. In the seventh Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with five MnS6 octahedra, corners with three GaS4 tetrahedra, and an edgeedge with one GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Ga–S bond distances ranging from 2.25–2.34 Å. In the eighth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with five MnS6 octahedra, corners with three GaS4 tetrahedra, and an edgeedge with one GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Ga–S bond distances ranging from 2.25–2.34 Å. In the ninth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with five MnS6 octahedra, corners with three GaS4 tetrahedra, and an edgeedge with one GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Ga–S bond distances ranging from 2.25–2.34 Å. In the tenth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with four MnS6 octahedra and corners with five GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–63°. There are a spread of Ga–S bond distances ranging from 2.26–2.38 Å. In the eleventh Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with four MnS6 octahedra and corners with five GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Ga–S bond distances ranging from 2.26–2.38 Å. In the twelfth Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three MnS6 octahedra and corners with six GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–62°. There are a spread of Ga–S bond distances ranging from 2.22–2.36 Å. There are twenty-four inequivalent S2- sites. In the first S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the second S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the third S2- site, S2- is bonded in a distorted trigonal planar geometry to one Mn2+ and two Ga3+ atoms. In the fourth S2- site, S2- is bonded to three Mn2+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SMn3Ga trigonal pyramids. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the sixth S2- site, S2- is bonded to three Mn2+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SMn3Ga trigonal pyramids. In the seventh S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the eighth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Mn2+ and one Ga3+ atom. In the ninth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the tenth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the eleventh S2- site, S2- is bonded in a 4-coordinate geometry to two Mn2+ and two Ga3+ atoms. In the twelfth S2- site, S2- is bonded to three Mn2+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SMn3Ga trigonal pyramids. In the thirteenth S2- site, S2- is bonded in a 4-coordinate geometry to two Mn2+ and two Ga3+ atoms. In the fourteenth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the fifteenth S2- site, S2- is bonded to three Mn2+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SMn3Ga trigonal pyramids. In the sixteenth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Ga3+ atoms. In the seventeenth S2- site, S2- is bonded in a trigonal planar geometry to one Mn2+ and two Ga3+ atoms. In the eighteenth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Mn2+ and one Ga3+ atom. In the nineteenth S2- site, S2- is bonded in a distorted trigonal planar geometry to one Mn2+ and two Ga3+ atoms. In the twentieth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Mn2+ and one Ga3+ atom. In the twenty-first S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Mn2+ and one Ga3+ atom. In the twenty-second S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Ga3+ atoms. In the twenty-third S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Ga3+ atoms. In the twenty-fourth S2- site, S2- is bonded in a distorted trigonal planar geometry to one Mn2+ and two Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(NO3)4 by Materials Project

Mn(NO3)4 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four Mn(NO3)4 clusters. In two of the Mn(NO3)4 clusters, Mn4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mn–O bond distances ranging from 2.01–2.50 Å. There are four inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.34 Å. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.32 Å. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.35 Å. In the fourth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.32 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted L-shaped geometry to one Mn4+ and one N5+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Mn4+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a distorted L-shaped geometry to one Mn4+ and one N5+ atom. In the seventh O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the ninth O2- site, O2- is bonded in an L-shaped geometry to one Mn4+ and one N5+ atom. In the tenth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the eleventh O2- site, O2- is bonded in an L-shaped geometry to one Mn4+ and one N5+ atom. In the twelfth O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In two of the Mn(NO3)4 clusters, Mn4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mn–O bond distances ranging from 2.02–2.44 Å. There are four inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.34 Å. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.34 Å. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.32 Å. In the fourth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.21–1.32 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the second O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the third O2- site, O2- is bonded in a distorted L-shaped geometry to one Mn4+ and one N5+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a distorted L-shaped geometry to one Mn4+ and one N5+ atom. In the seventh O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a water-like geometry to one Mn4+ and one N5+ atom. In the ninth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the tenth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one Mn4+ and one N5+ atom. In the twelfth O2- site, O2- is bonded in a distorted L-shaped geometry to one Mn4+ and one N5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(BH4)2 by Materials Project

Mn(BH4)2 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are five inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to eight H+0.50+ atoms to form distorted MnH8 hexagonal bipyramids that share edges with four BH4 tetrahedra. There are a spread of Mn–H bond distances ranging from 2.02–2.15 Å. In the second Mn2+ site, Mn2+ is bonded to eight H+0.50+ atoms to form distorted MnH8 hexagonal bipyramids that share edges with four BH4 tetrahedra. There are a spread of Mn–H bond distances ranging from 2.02–2.14 Å. In the third Mn2+ site, Mn2+ is bonded to eight H+0.50+ atoms to form distorted MnH8 hexagonal bipyramids that share edges with four BH4 tetrahedra. There are a spread of Mn–H bond distances ranging from 2.02–2.15 Å. In the fourth Mn2+ site, Mn2+ is bonded in a 8-coordinate geometry to eight H+0.50+ atoms. There are a spread of Mn–H bond distances ranging from 2.04–2.24 Å. In the fifth Mn2+ site, Mn2+ is bonded in a 8-coordinate geometry to eight H+0.50+ atoms. There are a spread of Mn–H bond distances ranging from 2.03–2.25 Å. There are ten inequivalent B3- sites. In the first B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share an edgeedge with one MnH8 hexagonal bipyramid. There are a spread of B–H bond distances ranging from 1.22–1.24 Å. In the second B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share an edgeedge with one MnH8 hexagonal bipyramid. There are a spread of B–H bond distances ranging from 1.22–1.24 Å. In the third B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two equivalent MnH8 hexagonal bipyramids. There is two shorter (1.23 Å) and two longer (1.24 Å) B–H bond length. In the fourth B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two MnH8 hexagonal bipyramids. There is two shorter (1.23 Å) and two longer (1.24 Å) B–H bond length. In the fifth B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two MnH8 hexagonal bipyramids. There is two shorter (1.23 Å) and two longer (1.24 Å) B–H bond length. In the sixth B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two equivalent MnH8 hexagonal bipyramids. There is two shorter (1.23 Å) and two longer (1.24 Å) B–H bond length. In the seventh B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two MnH8 hexagonal bipyramids. All B–H bond lengths are 1.23 Å. In the eighth B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two equivalent MnH8 hexagonal bipyramids. All B–H bond lengths are 1.23 Å. In the ninth B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. All B–H bond lengths are 1.23 Å. In the tenth B3- site, B3- is bonded in a tetrahedral geometry to four H+0.50+ atoms. All B–H bond lengths are 1.23 Å. There are thirty-five inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Mn2+ and one B3- atom. In the fourth H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Mn2+ and one B3- atom. In the fifth H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Mn2+ and one B3- atom. The H–B bond length is 1.22 Å. In the sixth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the seventh H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the eighth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. The H–B bond length is 1.24 Å. In the ninth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the tenth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the eleventh H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. The H–B bond length is 1.22 Å. In the twelfth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the thirteenth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the fourteenth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the fifteenth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the sixteenth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the seventeenth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the eighteenth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the nineteenth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twentieth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-first H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-second H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-third H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-fourth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-fifth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-sixth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-seventh H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-eighth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the twenty-ninth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the thirtieth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the thirty-first H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the thirty-second H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mn2+ and one B3- atom. In the thirty-third H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the thirty-fourth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom. In the thirty-fifth H+0.50+ site, H+0.50+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B3- atom.

36 MATERIALS SCIENCE↗