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All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Mn-Cr isotopic systematics of Chainpur chondrules and bulk ordinary chondrites

We report on ongoing study of the Mn-Cr systematics of individual Chainpur (LL3.4) chondrules and compare the results to those for bulk ordinary chondrites. Twenty-eight chondrules were surveyed for abundances of Mn, Cr, Na, Fe, Sc, Hf, Ir, and Zn by INAA. Twelve were chosen for SEM/EDX and high-precision Cr-isotopic studies on the basis of LL-chondrite-normalized Mn(LL), Sc(LL), (Mn/Fe)(LL), and (Sc/Fe)(LL) as well as their Mn/Cr ratios. Classification into textural types follows from SEM/EDX examination of interior surfaces.

Nyquist, L.↗
NASA NTRS1994

Mn-Cr isotopic systematics of individual Chainpur chondrules

Twenty-eight chondrules separated from Chainpur (LL3.4) were surveyed for abundances of Mn, Cr, Na, Fe, Sc, Hf, Ir, and Zn by Instrumental Neutron Activation Analysis (INAA). Six, weighting 0.6-1.5 mg each, were chosen for Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray (EDX) and high-precision Ce-isotopic studies. LL-chondrite-normalized (Mn/Fe)(sub LL) and (Sc/Fe)(sub LL) were found to be useful in categorizing them. Five chondrules (CH-16, -17, -18, -23, and -28) were in the range 0.5 less than (Mn/Fe)(sub LL) less than 1. 4 and 0.5 less than (Sc/Fe)(sub LL) less than 1.4. The sixth (CH-25) had (Mn/Fe)(sub LL) and (Sc/Fe)(sub LL) ratios of 0.40 and 8.1, respectively, and was enriched in the refractory lithophile elements Sc and Hf and the refractory siderophile element Ir by 2.7 and 4.4x LL abundances respectively. SEM/EDX of exterior surfaces of the chondrules showed they consisted of varying proportions of low- and high-Ca pyroxenes, olivine, glass, kamacite/taenite, and Fe-sulfides. Chromium-53/chromium-52 for the six chondrules and bulk Chainpur (WR) are presented. Chromium-54/chromium-52 is close to terrestrial and does not correlate with Mn/Cr. We provisionally ignore the possibility of initial Cr isotopic heterogeneities among the chondrules. Omitting both the CH-25 and WR data, a linear regression gives initial (Mn-53/Mn-55)(sub I) = 8 +/- 4 x 10(exp -6), corresponding to chondrule formation at Delta(t)(sub LEW) = -9 +/- 4 Ma prior to igneous crystallization of the LEW 86010 angrite. If initial (Mn-53/Mn-55)(sub 0) in the solar system were as high as approximately 4.4 x 10(exp -5) when Allende CAI formed, our data suggest Chainpur chondrules formed approximately 9 Ma later, in qualitative agreement with 'late' I-Xe formation ages for most Chainpur chondrules.

Nyquist, L.↗
NASA NTRS1998

Directional Solidification and Characterization of Hg(0.89) Mn(0.11)Te

Two boules of Hg(0.89)Mn(0.11)Te(MMT) were solidified using the vertical Bridgman-Stockbarger method. Translation rates of 0.09 and 0. 18 microns/s were used. The influence of growth rate on axial compositional homogeneity in the MMT boules was evaluated experimentally by conducting precision density measurements on radial slices taken from each boule. In addition, Plane Front Solidification theory and segregation coefficient (k) data for the Hg(1-x)Mn(x)Te system were used to fit theoretical composition profiles to the measured MMT axial composition profiles. The strong correlation between the measured and calculated MMT axial composition profiles indicates diffusion dominated axial solute redistribution in the boules under the applied growth conditions. The analysis of the MMT axial composition profiles by Plane Front Solidification theory allowed the calculation of the effective diffusion coefficient (D(eff) = 3.5 x l0(exp -5) sq cm/s). The k-values for the Hg(1-x)Mn(x)Te system and the D(sub eff) - value were then used to verify that both boules were solidified under conditions which did not exceed the Constitutional Supercooling Criteria under ideal conditions. Finally, a preliminary examination of the radial compositional variation in each MMT was made using Fourier Transform Infra-Red Spectroscopy (FTIR). The radial homogeneity in the MMT boules was found to be comparable for both translation rates.

Price, M. W.↗
NASA NTRS2004

Elevated Temperature Deformation of Fe-39.8Al and Fe-15.6Mn-39.4Al

The elevated temperature compressive properties of binary Fe-39.8 at % Al and Fe-15.6Mn-39.4Al have been measured between 1000 and 1300 K at strain rates between 10(exp 7) and 10(exp 3)/ s. Although the Mn addition to iron aluminide did not change the basic deformation characteristics, the Mn-modified alloy was slightly weaker. In the regime where deformation of FeAl occurs by a high stress exponent mechanism (n = 6), strength increases as the grain size decreases at least for diameters between approx. 200 and approx. 10 microns. Due to the limitation in the grain size-flow stress-temperature-strain rate database, the influence of further reductions of the grain size on strength is uncertain. Based on the appearance of subgrains in deformed iron aluminide, the comparison of grain diameters to expected subgrain sizes, and the grain size exponent and stress exponent calculated from deformation experiments, it is believed that grain size strengthening is the result of an artificial limitation on subgrain size as proposed by Sherby, Klundt and Miller.

Whittenberger, J. Daniel↗
NASA NTRS2006

Mn-53-Cr-53 Systematics of R-Chondrite NWA 753

Chondrules and chondrites are interpreted as objects formed in the early solar system, and it is important to study them in order to elucidate its evolution. Here, we report the study of the Mn-Cr systematics of the R-Chondrite NWA753 and compare the results to other chondrite data. The goal was to determine Cr isotopic and age variations among chondrite groups with different O-isotope signatures. The Mn-53-Cr-53 method as applied to individual chondrules [1] or bulk chondrites [2] is based on the assumption that 53Mn was initially homogeneously distributed in that portion the solar nebula where the chondrules and/or chondrites formed. However, different groups of chondrites formed from regions of different O-isotope compositions. So, different types of chondrites also may have had different initial Mn-53 abundances and/or Cr isotopic compositions. Thus, it is important to determine the Cr isotopic systematics among chondrites from various chondrite groups. We are studying CO-chondrite ALH83108 and Tagish Lake in addition to R-Chondrite NWA753. These meteorites have very distinct O-isotope compositions (Figure 1).

Jogo, K.↗
NASA NTRS2004

Direct Electrolytic Deposition of Mats of Mn(x)O(y) Nanowires

Mats of free-standing manganese oxide (MnxOy) nanowires have been fabricated as experimental electrode materials for rechargeable electrochemical power cells and capacitors. Because they are free-standing, the wires in these mats are electrochemically accessible. The advantage of the mat-of-nanowires configuration, relative to other configurations of electrode materials, arises from the combination of narrowness and high areal number density of the wires. This combination offers both high surface areas for contact with electrolytes and short paths for diffusion of ions into and out of the electrodes, thereby making it possible to charge and discharge at rates higher than would otherwise be possible and, consequently, to achieve greater power densities. The nanowires are fabricated in an electrolytic process in which there is no need for an electrode binder material. Moreover, there is no need to incorporate an electrically conductive additive into the electrode material; the only electrically conductive material that must be added is a thin substrate contact film at the anchored ends of the nanowires. Hence, the mass fraction of active electrode material is close to 100 percent, as compared with about 85 percent in conventional electrodes made from a slurry of active electrode material, binder, and conductive additive pressed onto a metal foil. The locations and sizes of the nanowires are defined by holes in templates in the form of commercially available porous alumina membranes. In experiments to demonstrate the present process, alumina membranes of various pore sizes and degrees of porosity were used. First, a film of Au was sputtered onto one side of each membrane. The membranes were then attached, variously, to carbon tape or a gold substrate by use of silver or carbon paste. Once thus attached, the membranes were immersed in a plating solution comprising 0.01 M MnSO4 + 0.03 M (NH4)2SO4. The pH of the solution was kept constant at 8 by addition of H2SO4 or NH4OH as needed. Mn(x)O(y) nanowires were potentiostatically electrodeposited in the pores in the alumina templates. Depending on the anodic deposition potentials, Mn(x)O(y) was deposited in various oxidation states [divalent (Mn3O4), trivalent (Mn2O3), or tetravalent (MnO2)]. The Mn(x)O(y) wires were made free-standing (see figure) by dissolving the alumina templates, variously, in KOH or NaOH at a concentration of 20 volume percent.

Myung, Nosang↗
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↗