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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Quantifying SEI Reaction Rate in the Presence and Absence of Mn 2+

In this work, a methodology utilizing potentiostatic holds is developed for measuring side-reaction rates at graphite (Gr) electrodes. The influence of Mn 2+ on parasitic reactions is evaluated in the presence of various preformed solid-electrolyte interphases (SEI). Gr SEI preformation was carried out using vinylene carbonate (VC) or lithium difluoro(oxalato)borate (LiDFOB) as an additive. In addition, a highly fluorinated electrolyte, free of traditional non-fluorinated organic carbonates, was used. Parasitic current increases were observed for all preformed Gr SEIs when Mn 2+ was present. Of the preforming electrolytes, the VC-derived SEI showed the lowest parasitic currents both with and without Mn 2+ .

Tornheim, Adam [Argonne National Laboratory (ANL),↗
DOE OSTI2022

Thermal dynamics of P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 cathode materials for sodium ion batteries studied by in situ analysis

Cobalt-free layered Na 0.67 Ni 0.33 Mn 0.67 O 2 is an attractive cathode material for sodium ion batteries. The thermal stability of cathode materials is crucial to their practical applications. In the current work, we investigate structural and morphological evolution in P2-type Na 0.67 Ni 0.33 Mn 0.67 O 2 cathode materials during annealing via in situ synchrotron X-ray diffraction and transmission electron microscopy. Insights are obtained from the two complementary in situ characterizations (at different length scales) in term of the thermal stability of P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 cathode materials. Here, the results indicate that the hexagonal P2 phase remains unchanged during the heat treatment process, and thermally driven expansion/contraction of lattice parameters exhibit an anisotropic character in the a and c directions. In addition, interfaces/grain boundaries play an important role in the structural stability, which leads to the distinct morphological evolution between the polycrystalline and single-crystal particles.

25 ENERGY STORAGE↗
DOE OSTI2020

Exploring the Charge Compensation Mechanism of P2-Type Na 0.6 Mg 0.3 Mn 0.7 O 2 Cathode Materials for Advanced Sodium-Ion Batteries

P2-type sodium layered transition metal oxides have been intensively investigated as promising cathode materials for sodium-ion batteries (SIBs) by virtue of their high specific capacity and high operating voltage. However, they suffer from problems of voltage decay, capacity fading, and structural deterioration, which hinder their practical application. Therefore, a mechanistic understanding of the cationic/anionic redox activity and capacity fading is indispensable for the further improvement of electrochemical performance. Here, a prototype cathode material of P2-type Na 0.6 Mg 0.3 Mn 0.7 O 2 is comprehensively investigated, which presents both cationic and anionic redox behaviors during the cycling process. By a combination of soft X-ray absorption spectroscopy and electroanalytical methods, we unambiguously reveal that only oxygen redox reaction is involved in the initial charge process, then both oxygen and manganese participate in the charge compensation in the following discharge process. In addition, a gradient distribution of Mn valence state from surface to bulk is disclosed, which could be mainly related to the irreversible oxygen activity during the charge process. Furthermore, we find that the average oxidation state of Mn is reduced upon extended cycles, leading to the noticeable capacity fading. Our results provide deeper insights into the intrinsic cationic/anionic redox mechanism of P2-type materials, which is vital for the rational design and optimization of advanced cathode materials for SIBs.

25 ENERGY STORAGE↗
DOE OSTI2020

Grain Refinement Effect on the Hot-Tearing Resistance of Higher-Temperature Al–Cu–Mn–Zr Alloys

The hot-tearing resistance of Al-Cu-Mn-Zr (ACMZ) alloys was investigated as a step toward introducing these new cast alloys for severe duty, higher-temperature applications, such as cylinder heads for down-sized, turbocharged automotive engines. Alloy Cu compositions were varied from 5 to 8 wt.%. Targeted Ti levels were 0.02, 0.1, and 0.2 wt.% via additions of the Al–5Ti–1B master alloy. Hot-tearing resistance was assessed by visual examination and ranking of the cracking severity in a multi-arm permanent mold casting. It was found that at high impurity contents (Fe and Si of 0.2 wt.% each), the Al–Cu–Mn–Zr alloy with 4.95 wt.% Cu exhibited the poorest hot-tearing resistance, irrespective of the grain refining amount. Microstructural analysis indicated an effective reduction in the grain size, as the Ti additions were increased to 0.02 and 0.1 wt.% Ti via the Al–Ti–B grain refiner. The finest grain size was attained with a 0.1 wt.% Ti. Based on the hot-tearing evaluation, it was found that the additional grain refining via the Al–5Ti–1B master alloy at 0.1 wt.% Ti significantly reduces the hot-tearing susceptibility at Cu contents greater than 7.3 wt.% for ACMZ alloys with low Fe and Si. These findings indicate that the best hot-tearing resistance was observed at a grain refiner level of 0.1 wt.% Ti and high Cu content (greater than 7.3 wt.%). This study to indicates that these Al–Cu–Mn–Zr alloys, which possess excellent microstructural stability and mechanical properties at elevated temperatures, can also possess excellent hot-tearing resistance.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Coexisting Multiple Martensites in Ni 57-x Mn 21+x Ga 22 Ferromagnetic Shape Memory Alloys: Crystal Structure and Phase Transition

A comprehensive study of the crystal structure and phase transition as a function of temperature and composition in Ni 57–x Mn 21+x Ga 22 (x = 0, 2, 4, 5.5, 7, 8) (at. %) magnetic shape memory alloys was performed by a temperature-dependent synchrotron X-ray diffraction technique and transmission electron microscopy. A phase diagram of this Ni 57–x Mn 21+x Ga 22 alloy system was constructed. The transition between coexisting multiple martensites with monoclinic and tetragonal structures during cooling was observed in the Ni 51.5 Mn 26.5 Ga 22 (x = 5.5) alloy, and it was found that 5M + 7M multiple martensites coexist from 300 K to 160 K and that 5M + 7M + NM multiple martensites coexist between 150 K and 100 K. The magnetic-field-induced transformation from 7M martensite to NM martensite at 140 K where 5M + 7M + NM multiple martensites coexist before applying the magnetic field was observed by in situ neutron diffraction experiments. The present study is instructive for understanding the phase transition between coexisting multiple martensites under external fields and may shed light on the design of novel functional properties based on such phase transitions.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Inhomogeneous Enrichment of Radioactive Nuclei in the Galaxy: Deposition of Live 53 Mn, 60 Fe, 182 Hf, and 244 Pu into Deep-sea Archives. Surfing the Wave?

Abstract While modeling the galactic chemical evolution (GCE) of stable elements provides insights to the formation history of the Galaxy and the relative contributions of nucleosynthesis sites, modeling the evolution of short-lived radioisotopes (SLRs) can provide supplementary timing information on recent nucleosynthesis. To study the evolution of SLRs, we need to understand their spatial distribution. Using a three-dimensional GCE model, we investigated the evolution of four SLRs: 53 Mn, 60 Fe, 182 Hf, and 244 Pu with the aim of explaining detections of recent (within the last ≈1–20 Myr) deposition of live 53 Mn, 60 Fe, and 244 Pu of extrasolar origin into deep-sea reservoirs. We find that core-collapse supernovae are the dominant propagation mechanism of SLRs in the Galaxy. This results in the simultaneous arrival of these four SLRs on Earth, although they could have been produced in different astrophysical sites, which can explain why live extrasolar 53 Mn, 60 Fe, and 244 Pu are found within the same, or similar, layers of deep-sea sediments. We predict that 182 Hf should also be found in such sediments at similar depths.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Piezocatalytic ZnS:Mn 2+ Nanocrystals for Enhanced Organic Dye Degradation

Piezocatalysis, an emerging approach that harnesses mechanical energy to drive chemical reactions, has garnered significant attention due to its potential applications in diverse fields, particularly in environmental remediation. Its broader application, however, is often hindered by the low efficiency of existing piezocatalytic materials. Here, we report the synthesis of Mn 2+ -doped ZnS nanocrystals with improved piezoelectric properties using an emulsion-based colloidal assembly technique. Through well-controlled Mn 2+ doping, these nanocrystals demonstrate high piezocatalytic activity for degrading organic dyes under ultrasonic vibration. The optimal performance is achieved with 3% Mn 2+ doping, outperforming many existing piezocatalysts. Mechanistic studies reveal the generation of reactive oxygen species as the primary driving force for degradation. Notably, pre-excitation with UV light further boosts the piezocatalytic efficiency of these metal ion-doped ZnS nanocrystals by filling electron trap states, leading to improved overall performance. This research paves the way for developing high-performance piezocatalysts, expanding the potential of piezocatalysis for a wide range of applications.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Assessment of UTP A 2133 Mn as a Matching Filler Metal for Alloy 800H in Section III, Division 5 Applications

Six alloys are qualified in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) for elevated-temperature nuclear components. Due to reactor design alloy restrictions and motivation to improve operational efficiency and plant lifetimes, it is necessary to maximize the usefulness of qualified alloys. One of these alloys is Alloy 800H, which is qualified for a maximum temperature of 760°C and a maximum 300,000-hour service life. However, the welding filler metals qualified to join Alloy 800H have stress rupture factors that reduce the allowable weldment strength by factors as low as 0.59 times the Alloy 800H base metal. In an effort to improve the weldment creep-rupture performance, or to increase the stress reduction factor, non-code qualified filler metals are under investigation by the Department of Energy?s Advanced Reactor Technologies program. For this investigation, UTP A 2133 Mn filler metal (Fe-Cr-Ni-Mn-Nb) was used to join 0.5 in. thick Alloy 800H plate to demonstrate passing an ASME BPVC Section IX weld qualification. The multi-pass, pulsed GTAW process showed successful weld qualification results, and additional property measurements were conducted to compare previous analyses of Alloy 82 and Alloy 617 filler metals. Future work will evaluate the cross-weld creep-rupture performance of the UTP A 2133 Mn in comparison to Alloy 82 and Alloy 617 filler metals.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Mn(BW)2 by Materials Project

Mn(WB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. W2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.34 Å) and four longer (2.35 Å) W–B bond lengths. Mn2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Mn–B bond lengths are 2.34 Å. B3- is bonded in a 9-coordinate geometry to six equivalent W2+, two equivalent Mn2+, and one B3- atom. The B–B bond length is 1.87 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(PO3)4 by Materials Project

Mn(PO3)4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Mn–O bond distances ranging from 1.89–1.96 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–50°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of P–O bond distances ranging from 1.46–1.67 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent P5+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent P5+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(PO3)4 by Materials Project

Mn(PO3)4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Mn–O bond distances ranging from 1.90–1.97 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of P–O bond distances ranging from 1.46–1.67 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of P–O bond distances ranging from 1.46–1.65 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–49°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MnO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–50°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn4+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn4+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn4+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(NbS2)4 by Materials Project

Mn(NbS2)4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six S2- atoms to form distorted NbS6 pentagonal pyramids that share corners with four equivalent MnS6 octahedra and edges with six NbS6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 48°. There are two shorter (2.47 Å) and four longer (2.51 Å) Nb–S bond lengths. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six equivalent S2- atoms to form distorted NbS6 pentagonal pyramids that share edges with six equivalent NbS6 pentagonal pyramids and faces with two equivalent MnS6 octahedra. All Nb–S bond lengths are 2.50 Å. Mn2+ is bonded to six equivalent S2- atoms to form MnS6 octahedra that share corners with twelve equivalent NbS6 pentagonal pyramids and faces with two equivalent NbS6 pentagonal pyramids. All Mn–S bond lengths are 2.48 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Nb+3.50+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(PO3)3 by Materials Project

Mn(PO3)3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mn3+ is bonded to five O2- atoms to form MnO5 trigonal bipyramids that share corners with five PO4 tetrahedra. There are a spread of Mn–O bond distances ranging from 1.91–2.08 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and corners with two equivalent MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and a cornercorner with one MnO5 trigonal bipyramid. There are a spread of P–O bond distances ranging from 1.46–1.64 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and corners with two equivalent MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(PO3)3 by Materials Project

Mn(PO3)3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mn3+ is bonded to five O2- atoms to form distorted MnO5 trigonal bipyramids that share corners with five PO4 tetrahedra. There are a spread of Mn–O bond distances ranging from 1.95–2.11 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and corners with two equivalent MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and corners with two equivalent MnO5 trigonal bipyramids. There are a spread of P–O bond distances ranging from 1.48–1.63 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two PO4 tetrahedra and a cornercorner with one MnO5 trigonal bipyramid. There are a spread of P–O bond distances ranging from 1.47–1.65 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mn3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mn3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a distorted linear geometry to one Mn3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(CoO2)4 by Materials Project

Mn(CoO2)4 is beta indium sulfide-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mn7+ is bonded to six O2- atoms to form MnO6 octahedra that share edges with eight CoO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–1.94 Å. There are four inequivalent Co+2.25+ sites. In the first Co+2.25+ site, Co+2.25+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, edges with two equivalent MnO6 octahedra, and edges with four CoO6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Co–O bond distances ranging from 2.04–2.16 Å. In the second Co+2.25+ site, Co+2.25+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, edges with two equivalent MnO6 octahedra, and edges with four CoO6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are two shorter (2.02 Å) and four longer (2.05 Å) Co–O bond lengths. In the third Co+2.25+ site, Co+2.25+ is bonded to six O2- atoms to form CoO6 octahedra that share edges with two equivalent MnO6 octahedra and edges with six CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.88–1.91 Å. In the fourth Co+2.25+ site, Co+2.25+ is bonded to six O2- atoms to form CoO6 octahedra that share edges with two equivalent MnO6 octahedra and edges with six CoO6 octahedra. There is two shorter (1.91 Å) and four longer (1.92 Å) Co–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to one Mn7+ and two Co+2.25+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn7+ and three Co+2.25+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn7+ and three Co+2.25+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Co+2.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(CrSe2)2 by Materials Project

Mn(CrSe2)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six equivalent MnSe6 octahedra, edges with six equivalent CrSe6 octahedra, and a faceface with one MnSe6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are a spread of Cr–Se bond distances ranging from 2.52–2.62 Å. Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with twelve equivalent CrSe6 octahedra, edges with two equivalent MnSe6 octahedra, and faces with two equivalent CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are two shorter (2.63 Å) and four longer (2.69 Å) Mn–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cr3+ and two equivalent Mn2+ atoms to form a mixture of distorted corner and edge-sharing SeMn2Cr3 trigonal bipyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three equivalent Cr3+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(AlTe2)2 by Materials Project

Mn(AlTe2)2 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. Mn2+ is bonded to four equivalent Te2- atoms to form MnTe4 tetrahedra that share corners with eight equivalent AlTe4 tetrahedra. All Mn–Te bond lengths are 2.73 Å. Al3+ is bonded to four equivalent Te2- atoms to form AlTe4 tetrahedra that share corners with four equivalent MnTe4 tetrahedra and corners with four equivalent AlTe4 tetrahedra. All Al–Te bond lengths are 2.67 Å. Te2- is bonded in a trigonal non-coplanar geometry to one Mn2+ and two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(NbSe2)4 by Materials Project

Mn(NbSe2)4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share edges with six equivalent NbSe6 pentagonal pyramids and faces with two equivalent MnSe6 octahedra. All Nb–Se bond lengths are 2.64 Å. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with four equivalent MnSe6 octahedra and edges with six NbSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 49°. There are two shorter (2.59 Å) and four longer (2.64 Å) Nb–Se bond lengths. Mn2+ is bonded to six equivalent Se2- atoms to form MnSe6 octahedra that share corners with twelve equivalent NbSe6 pentagonal pyramids and faces with two equivalent NbSe6 pentagonal pyramids. All Mn–Se bond lengths are 2.60 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Nb+3.50+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗