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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Impact of Mg Substitution on the Structure, Stability, and Properties of the Na 2 Fe 2 F 7 Weberite Cathode

Of the few weberite-type Na-ion cathodes explored to date, Na 2 Fe 2 F 7 exhibits the best performance, with capacities up to 184 mAh/g and energy densities up to 550 Wh/kg reported for this material. However, the development of robust structure–property relationships for this material is complicated by its tendency to form as a mixture of metastable polymorphs, and transform to a lower-energy Na y FeF 3 perovskite compound during electrochemical cycling. Our first-principles-guided exploration of Fe-based weberite solid solutions with redox-inactive Mg 2+ and Al 3+ predicts an enhanced thermodynamic stability of Na 2 Mg x Fe 2–x F 7 as the Mg content is increased, and the x = 0.125 composition is selected for further exploration. We demonstrate that the monoclinic polymorph (space group C2/c) of Na 2 Fe 2 F 7 (Mg0) and of a new Mg-substituted weberite composition, Na 2 Mg 0.125 Fe 1.875 F 7 (Mg0.125), can be isolated using an optimized synthesis protocol. The impact of Mg substitution on the stability of the weberite phase during electrochemical cycling, and on the extent and rate of Na (de)intercalation, is examined. Irrespective of the Mg content, we find that the weberite phase is retained when cycling over a narrow voltage window (2.8–4.0 V vs Na/Na+). Over a wider voltage range (1.9–4.0 V), Mg0 shows steady capacity fade due to its transformation to the NayFeF3 perovskite phase, while Mg0.125 displays more reversible cycling and a reduced phase transformation. Yet, Mg incorporation also leads to kinetically limited Na extraction and a reduced overall capacity. These findings highlight the need for the continued compositional optimization of weberite cathodes to improve their structural stability while maximizing their energy density.

25 ENERGY STORAGE↗
DOE OSTI2025

Ultraselective sequestration of Li + and Mg 2+ from brines via a reusable polyoxoniobate-based ion sponge

Lithium (Li) and magnesium (Mg) are designated as critical mineral materials (CMM) due to their essential roles in clean energy technologies. However, extracting high-purity Li + from brine remains a formidable challenge owing to the presence of Mg 2+ , a physicochemical similar ion that often exists in excess. Here, we introduce a polyoxoniobate-based “Mg-PONb sponge” that enables ultraselective and rapid Li + /Mg 2+ separation across an exceptionally broad range of Mg/Li ratios (0.02 to 200.63). This framework achieves >99.9% Mg 2+ removal with negligible Li + loss in under 1 min, yielding Li + /Mg 2+ selectivity values exceeding 5000. The sponge demonstrates excellent recyclability, maintaining >99% Mg 2+ rejection and Li + permeability across five regeneration cycles without structural degradation. Mechanistic investigations reveal that selective Mg 2+ capture originates from strong coordination with terminal oxygens on the PONb cluster, driving rapid formation of porous Mg-PONb frameworks. This work presents a generalizable, scalable strategy for Li + /Mg 2+ separation and offers a sustainable path toward enhanced Li and Mg recovery from complex brine sources.

Chen, Linfeng [Lawrence Berkeley National Laborato↗
DOE OSTI2023

Proton branching ratios in 22 Mg for X-ray bursts

Here, decay protons from 22 Mg energy levels populated through a previously reported 24 Mg(p, t) 22 Mg transfer reaction (Chae et al. in Phys Rev C 79:055804, 2009) have been analyzed for proton branching ratios as a follow-up analysis. The measurement was performed at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory by utilizing 41-MeV proton beams and 24 Mg solid targets. Decay protons and reaction tritons were simultaneously detected with a silicon detector array. By investigating the 24 Mg(p, t) 22 Mg*(p) 21 Na channels, the proton branching ratios of five 22 Mg excited states were obtained. The measured branching ratios provide constraints on the proton partial widths of the populated 22 Mg levels, which have implications for X-ray burst nucleosynthesis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Demonstration of MgCr 2– x Mn x O 4 Spinel Oxide Cathodes in High-Voltage Mg Batteries

Solid-solution oxide spinels with high redox voltages and facile Mg 2+ mobility have been identified as promising candidates for practical, high-voltage cathodes in Mg batteries. In this work, we discuss the development of MgCr 2-x Mn x O 4 [x = 0.5, 1, 1.2] solid-solution spinel oxides as a cathode material and their electrochemical performance paired with an Mg anode in a full cell. This work presents the first demonstration of full cells with these materials. Mg-Cr-Mn spinel oxides with varying Cr and Mn contents were synthesized using alternative synthetic routes for optimal electrochemical performance. High-resolution synchrotron powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (NMR) spectroscopy, and electron microscopy showed that these different synthetic routes resulted in changes in structures and particle morphologies, which in turn affect the electrochemical performance. Particularly, the urea coprecipitation synthetic route resulted in high-surface-area particles that enabled lower overpotentials and increased discharge capacity. The high surface area also resulted in expedited structural degradation caused by the irreversible migration of Mg 2+ into normally vacant 16c sites in the spinel lattice. This structural degradation was lessened by using a hydrosauna-urea synthesis method, which decreased the Mg/Mn inversion ratio while retaining high-surface-area particles with good cycling performance. Furthermore, our findings highlight the necessity for high surface area or nanostructured spinel oxide cathodes with minimized Mg-Mn inversion to enable spinel oxide cathodes in Mg full cells.

Mg anode↗
DOE OSTI2021

Synthesis of High-Quality Mg-MOF-74 Thin Films via Vapor-Assisted Crystallization

The unique features of metal-organic frameworks (MOFs), such as their large surface areas and diversity of structures, makes them suitable to a broad range of applications. One of the most critical enabling technologies for implementing MOF films is the preparation of dense and continuous films that would maximize the performance of the configurations. While formation of crystalline Mg-MOF-74 thin films presents significant challenges, demonstrating large-scale coatings of the MOF, which exhibits the highest CO2 uptake among MOFs at 1 bar and 25 °C, would be particularly beneficial for CO2- related sensing applications. In this work, we demonstrate for the first time high-quality Mg-MOF-74 films synthesized via a vapor-assisted crystallization (VAC) process. The VAC process described herein produces dense and highly crystalline layers of Mg-MOF-74 with a low coefficient of variation (COV) of film thickness below 7%. We first optimized a precursor solution for the VAC process, and then investigated the effects of synthesis temperature, time and droplet volume on the growth, crystallinity and thickness of Mg-MOF-74 films. The porosity of the film was assessed by measuring the CO2 uptake at room temperature and 1 bar. The obtained Mg-MOF-74 films possess a well-defined microporosity, as deduced from CO2 adsorption studies via quartz crystal microbalance (QCM) and comparison with bulk Mg MOF-74 reference data. Furthermore, CO2 cyclic adsorption-desorption experiments on the Mg-MOF-74

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

Materials Data on Mg(CoGe)6 by Materials Project

Mg(CoGe)6 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Mg is bonded in a 8-coordinate geometry to twelve equivalent Co and eight Ge atoms. All Mg–Co bond lengths are 3.19 Å. There are two shorter (2.60 Å) and six longer (2.93 Å) Mg–Ge bond lengths. Co is bonded in a 12-coordinate geometry to two equivalent Mg, four equivalent Co, and six Ge atoms. All Co–Co bond lengths are 2.54 Å. There are four shorter (2.42 Å) and two longer (2.62 Å) Co–Ge bond lengths. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 6-coordinate geometry to six equivalent Co atoms. In the second Ge site, Ge is bonded in a 12-coordinate geometry to three equivalent Mg and six equivalent Co atoms. In the third Ge site, Ge is bonded in a 8-coordinate geometry to one Mg, six equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.51 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(AgO2)2 by Materials Project

Mg(AgO2)2 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 50–62°. There are a spread of Mg–O bond distances ranging from 2.04–2.09 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six AgO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.09–2.15 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.10–2.15 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six AgO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.10–2.14 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six AgO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AgO6 octahedra. There are four shorter (2.09 Å) and two longer (2.13 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.15 Å. There are twelve inequivalent Ag3+ sites. In the first Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AgO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.23 Å. In the second Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six MgO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 57–65°. There are three shorter (2.18 Å) and one longer (2.23 Å) Ag–O bond lengths. In the third Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AgO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.10–2.25 Å. In the fourth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AgO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.24 Å. In the fifth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with six AgO4 tetrahedra, edges with two equivalent AgO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.07–2.15 Å. In the sixth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six MgO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Ag–O bond distances ranging from 2.16–2.19 Å. In the seventh Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with six AgO4 tetrahedra, edges with two equivalent AgO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.07–2.15 Å. In the eighth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AgO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.21 Å. In the ninth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six MgO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 57–64°. There are a spread of Ag–O bond distances ranging from 2.13–2.19 Å. In the tenth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AgO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.20 Å. In the eleventh Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six MgO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Ag–O bond distances ranging from 2.17–2.19 Å. In the twelfth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 58–63°. There are a spread of Ag–O bond distances ranging from 2.12–2.21 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ag3+ atoms. In the second O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 tetrahedra that share corners with six OMg2Ag2 tetrahedra and corners with six OMgAg3 trigonal pyramids. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ag3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Ag3+ atoms. In the fifth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with seven OMg2Ag2 tetrahedra, corners with five OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the sixth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMgAg3 tetrahedra, corners with two OMgAg3 trigonal pyramids, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the seventh O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the eighth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with five OMgAg3 tetrahedra, corners with three OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the ninth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with seven OMg2Ag2 tetrahedra, corners with five OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the tenth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with five OMgAg3 tetrahedra, a cornercorner with one OAg4 trigonal pyramid, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with seven OMg2Ag2 tetrahedra, corners with five OMgAg3 trigonal pyramids, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the twelfth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with five OMgAg3 tetrahedra, corners with three OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the fifteenth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Ag3+ atoms. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, edges with two OMg2Ag2 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the nineteenth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMg2Ag2 tetrahedra, corners with six OAg4 trigonal pyramids, and edges with two OMg2Ag2 tetrahedra. In the twentieth O2- site, O2- is bonded to two Mg2+ and two Ag3+ atoms to form distorted OMg2Ag2 tetrahedra that share corners with six OMg2Ag2 tetrahedra, corners with six OMgAg3 trigonal pyramids, an edgeedge with one OMg2Ag2 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the twenty-first O2- site, O2- is bonded to four Ag3+ atoms to form distorted OAg4 trigonal pyramids that share corners with four OMg2Ag2 tetrahedra, corners with three OMgAg3 trigonal pyramids, edges with two OMgAg3 tetrahedra, and an edgeedge with one OMgAg3 trigonal pyramid. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 tetrahedra that share corners with four OMg2Ag2 tetrahedra, corners with three OMgAg3 trigonal pyramids, an edgeedge with one OMgAg3 tetrahedra, and edges with two OMgAg3 trigonal pyramids. In the twenty-third O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 trigonal pyramids that share corners with six OMg2Ag2 tetrahedra, corners with three OMgAg3 trigonal pyramids, edges with two OMgAg3 tetrahedra, and an edgeedge with one OAg4 trigonal pyramid. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three Ag3+ atoms to form distorted OMgAg3 tetrahedra that share corners with four OMg2Ag2 tetrahedra, corners with three OMgAg3 trigonal pyramids, an edgeedge with one OMgAg3 tetrahedra, and edges with two OMgAg3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(SnO2)2 by Materials Project

Mg(SnO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Mg–O bond distances ranging from 2.03–2.46 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six SnO4 tetrahedra, edges with two MgO6 octahedra, and edges with four SnO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.23–2.27 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with three SnO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.30 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six SnO4 tetrahedra, edges with two MgO6 octahedra, and edges with four SnO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.18–2.25 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SnO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent SnO6 octahedra. There are two shorter (2.10 Å) and four longer (2.23 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with three SnO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.11–2.37 Å. There are nine inequivalent Sn3+ sites. In the first Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with three SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with three MgO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.07–2.21 Å. In the second Sn3+ site, Sn3+ is bonded to four O2- atoms to form SnO4 tetrahedra that share corners with six MgO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 56–68°. There are a spread of Sn–O bond distances ranging from 2.19–2.63 Å. In the third Sn3+ site, Sn3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sn–O bond distances ranging from 2.31–2.75 Å. In the fourth Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with six SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.09–2.15 Å. In the fifth Sn3+ site, Sn3+ is bonded to four O2- atoms to form SnO4 tetrahedra that share corners with six MgO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 59–66°. There are a spread of Sn–O bond distances ranging from 2.22–2.57 Å. In the sixth Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with three SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with three MgO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.07–2.18 Å. In the seventh Sn3+ site, Sn3+ is bonded to four O2- atoms to form SnO4 tetrahedra that share corners with six MgO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 56–69°. There are a spread of Sn–O bond distances ranging from 2.20–2.52 Å. In the eighth Sn3+ site, Sn3+ is bonded to four O2- atoms to form SnO4 tetrahedra that share corners with six MgO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 57–69°. There are a spread of Sn–O bond distances ranging from 2.20–2.48 Å. In the ninth Sn3+ site, Sn3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Sn–O bond distances ranging from 2.12–2.75 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Sn3+ atoms. In the second O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form distorted corner-sharing OMgSn3 tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Sn3+ atoms. In the fourth O2- site, O2- is bonded to two Mg2+ and two Sn3+ atoms to form OMg2Sn2 tetrahedra that share corners with twelve OMgSn3 tetrahedra and edges with three OMg2Sn2 tetrahedra. In the fifth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form OMgSn3 tetrahedra that share corners with eight OMgSn3 tetrahedra and edges with two equivalent OMg2Sn2 tetrahedra. In the sixth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form a mixture of distorted edge and corner-sharing OMgSn3 tetrahedra. In the seventh O2- site, O2- is bonded to two Mg2+ and two Sn3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sn2 tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+ and three Sn3+ atoms. In the ninth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form distorted OMgSn3 tetrahedra that share corners with twelve OMgSn3 tetrahedra and edges with three OMg2Sn2 tetrahedra. In the tenth O2- site, O2- is bonded to two Mg2+ and two Sn3+ atoms to form distorted OMg2Sn2 tetrahedra that share corners with eight OMgSn3 tetrahedra, a cornercorner with one OSn4 trigonal pyramid, and edges with two OMg2Sn2 tetrahedra. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form a mixture of edge and corner-sharing OMgSn3 tetrahedra. In the twelfth O2- site, O2- is bonded to two Mg2+ and two Sn3+ atoms to form distorted OMg2Sn2 tetrahedra that share corners with twelve OMg2Sn2 tetrahedra and edges with three OMgSn3 tetrahedra. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Sn3+ atoms. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form distorted OMgSn3 tetrahedra that share corners with twelve OMg2Sn2 tetrahedra and edges with three OMgSn3 tetrahedra. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form OMgSn3 tetrahedra that share corners with eight OMgSn3 tetrahedra, corners with two equivalent OSn4 trigonal pyramids, and edges with two equivalent OMg2Sn2 tetrahedra. In the sixteenth O2- site, O2- is bonded to four Sn3+ atoms to form distorted OSn4 trigonal pyramids that share corners with four OMg2Sn2 tetrahedra and an edgeedge with one OMgSn3 tetrahedra. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and three Sn3+ atoms. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Sn3+ atoms to form distorted OMgSn3 tetrahedra that share corners with nine OMg2Sn2 tetrahedra and an edgeedge with one OSn4 trigonal pyramid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(WO2)2 by Materials Project

Mg(WO2)2 is Ilmenite-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are three shorter (2.04 Å) and one longer (2.13 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six WO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.10–2.21 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four WO4 trigonal pyramids, an edgeedge with one MgO6 octahedra, and edges with five WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.12–2.16 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share edges with two MgO6 octahedra and edges with four WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.11–2.18 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three WO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four equivalent WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.09–2.17 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, an edgeedge with one MgO6 octahedra, and edges with five WO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.24 Å. There are nine inequivalent W3+ sites. In the first W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four WO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.17–2.22 Å. In the second W3+ site, W3+ is bonded to four O2- atoms to form WO4 trigonal pyramids that share corners with six MgO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 39–69°. There are a spread of W–O bond distances ranging from 2.01–2.55 Å. In the third W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent WO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four WO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.18 Å. In the fourth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three WO4 trigonal pyramids, edges with two equivalent WO6 octahedra, and edges with four MgO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.25 Å. In the fifth W3+ site, W3+ is bonded in a trigonal planar geometry to three O2- atoms. All W–O bond lengths are 2.02 Å. In the sixth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with two equivalent WO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.23 Å. In the seventh W3+ site, W3+ is bonded to four O2- atoms to form WO4 trigonal pyramids that share corners with six MgO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 39–69°. There are a spread of W–O bond distances ranging from 2.01–2.47 Å. In the eighth W3+ site, W3+ is bonded in a trigonal planar geometry to three O2- atoms. All W–O bond lengths are 2.02 Å. In the ninth W3+ site, W3+ is bonded to four O2- atoms to form WO4 trigonal pyramids that share corners with three MgO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 45–67°. There are a spread of W–O bond distances ranging from 2.00–2.38 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two W3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two W3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent W3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two W3+ atoms. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+ and three W3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two W3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two W3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent W3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four W3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three W3+ atoms. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent W3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(MoO2)2 by Materials Project

Mg(MoO2)2 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 52–61°. There are a spread of Mg–O bond distances ranging from 2.02–2.10 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MoO4 tetrahedra, corners with three equivalent MoO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.10–2.14 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with two equivalent MoO4 tetrahedra, corners with two MoO4 trigonal pyramids, an edgeedge with one MgO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.14–2.16 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MoO4 tetrahedra, corners with three equivalent MoO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.16 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MoO4 tetrahedra, corners with three MoO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.20 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, a cornercorner with one MoO4 tetrahedra, corners with four MoO4 trigonal pyramids, an edgeedge with one MgO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.19 Å. There are twelve inequivalent Mo3+ sites. In the first Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with two equivalent MoO4 tetrahedra, corners with two MoO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.17–2.22 Å. In the second Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 trigonal pyramids that share corners with six MgO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 43–67°. There are a spread of Mo–O bond distances ranging from 2.01–2.35 Å. In the third Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent MoO4 trigonal pyramids, edges with two MgO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.11–2.21 Å. In the fourth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with two equivalent MoO4 tetrahedra, corners with two MoO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.05–2.16 Å. In the fifth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three MoO4 tetrahedra, corners with three MoO4 trigonal pyramids, edges with two equivalent MoO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.11–2.22 Å. In the sixth Mo3+ site, Mo3+ is bonded to four O2- atoms to form distorted MoO4 trigonal pyramids that share corners with six MgO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 37–72°. There are a spread of Mo–O bond distances ranging from 1.99–2.65 Å. In the seventh Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three MoO4 tetrahedra, corners with three MoO4 trigonal pyramids, edges with two equivalent MoO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.11–2.24 Å. In the eighth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share a cornercorner with one MgO4 tetrahedra, a cornercorner with one MoO4 tetrahedra, corners with four MoO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.17–2.19 Å. In the ninth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six MgO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 48–67°. There are a spread of Mo–O bond distances ranging from 2.02–2.30 Å. In the tenth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share a cornercorner with one MgO4 tetrahedra, a cornercorner with one MoO4 tetrahedra, corners with four MoO4 trigonal pyramids, edges with three MgO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.14–2.21 Å. In the eleventh Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six MgO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 50–70°. There are a spread of Mo–O bond distances ranging from 2.09–2.15 Å. In the twelfth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 trigonal pyramids that share corners with three MgO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 47–72°. There are a spread of Mo–O bond distances ranging from 2.08–2.40 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the second O2- site, O2- is bonded to one Mg2+ and three Mo3+ atoms to form distorted corner-sharing OMgMo3 trigonal pyramids. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+ and three Mo3+ atoms. In the eighth O2- site, O2- is bonded to two Mg2+ and two Mo3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Mo2 trigonal pyramids. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three Mo3+ atoms to form distorted OMgMo3 trigonal pyramids that share corners with two OMgMo3 tetrahedra, corners with four OMo4 trigonal pyramids, and an edgeedge with one OMg2Mo2 trigonal pyramid. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Mo3+ atoms. In the twenty-first O2- site, O2- is bonded to four Mo3+ atoms to form a mixture of distorted corner and edge-sharing OMo4 trigonal pyramids. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three Mo3+ atoms to form distorted OMgMo3 tetrahedra that share a cornercorner with one OMgMo3 tetrahedra, corners with two OMo4 trigonal pyramids, an edgeedge with one OMgMo3 tetrahedra, and an edgeedge with one OMo4 trigonal pyramid. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Mo3+ atoms. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three Mo3+ atoms to form distorted OMgMo3 tetrahedra that share a cornercorner with one OMgMo3 tetrahedra, corners with two OMo4 trigonal pyramids, an edgeedge with one OMgMo3 tetrahedra, and an edgeedge with one OMo4 trigonal pyramid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(Co2Ge3)2 by Materials Project

Mg(Co2Ge3)2 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. Mg is bonded to four equivalent Co and eight Ge atoms to form distorted corner-sharing MgCo4Ge8 cuboctahedra. All Mg–Co bond lengths are 2.89 Å. There are four shorter (2.95 Å) and four longer (3.09 Å) Mg–Ge bond lengths. Co is bonded in a 7-coordinate geometry to one Mg and six Ge atoms. There are a spread of Co–Ge bond distances ranging from 2.29–2.48 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 5-coordinate geometry to one Mg and four equivalent Co atoms. In the second Ge site, Ge is bonded in a 6-coordinate geometry to two equivalent Mg and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(NO4)2 by Materials Project

Mg(NO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Mg(NO4)2 sheet oriented in the (1, 0, 0) direction. Mg is bonded in an octahedral geometry to six O atoms. There are a spread of Mg–O bond distances ranging from 2.09–2.16 Å. N is bonded in a trigonal planar geometry to three O atoms. There are a spread of N–O bond distances ranging from 1.23–1.30 Å. There are four inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Mg and one N atom. In the second O site, O is bonded in a single-bond geometry to one N atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Mg and one N atom. In the fourth O site, O is bonded in a single-bond geometry to one Mg atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BO4)4 by Materials Project

(MgB4O15)2O2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four water molecules and one MgB4O15 framework. In the MgB4O15 framework, Mg is bonded to five O atoms to form distorted MgO5 trigonal bipyramids that share a cornercorner with one BO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.28 Å. There are four inequivalent B sites. In the first B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.55 Å. In the second B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.37–1.39 Å. In the third B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one BO4 tetrahedra and a cornercorner with one MgO5 trigonal bipyramid. There are a spread of B–O bond distances ranging from 1.44–1.50 Å. In the fourth B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.24 Å. In the second O site, O is bonded in a single-bond geometry to one Mg atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Mg and one O atom. In the fourth O site, O is bonded in a single-bond geometry to one B atom. In the fifth O site, O is bonded in a single-bond geometry to one Mg atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to two B atoms. In the seventh O site, O is bonded in a single-bond geometry to one B atom. In the eighth O site, O is bonded in a single-bond geometry to one Mg atom. In the ninth O site, O is bonded in a bent 120 degrees geometry to two B and one O atom. The O–O bond length is 1.69 Å. In the tenth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the eleventh O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the twelfth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the thirteenth O site, O is bonded in a linear geometry to two equivalent O atoms. In the fourteenth O site, O is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There is two shorter (1.87 Å) and two longer (1.89 Å) O–O bond length. In the fifteenth O site, O is bonded in a single-bond geometry to one B and one O atom. In the sixteenth O site, O is bonded in a distorted bent 120 degrees geometry to one Mg, one B, and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BO2)12 by Materials Project

Mg(BO2)12 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Mg(BO2)12 sheet oriented in the (0, 0, 1) direction. Mg is bonded to six O atoms to form MgO6 octahedra that share corners with eight BO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.18 Å. There are six inequivalent B sites. In the first B site, B is bonded in a trigonal planar geometry to three O atoms. There are a spread of B–O bond distances ranging from 1.37–1.39 Å. In the second B site, B is bonded in a trigonal planar geometry to three O atoms. All B–O bond lengths are 1.38 Å. In the third B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one MgO6 octahedra and a cornercorner with one BO4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. There is two shorter (1.45 Å) and two longer (1.47 Å) B–O bond length. In the fourth B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with three BO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of B–O bond distances ranging from 1.45–1.49 Å. In the fifth B site, B is bonded to four O atoms to form BO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with two equivalent BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–63°. There are a spread of B–O bond distances ranging from 1.45–1.50 Å. In the sixth B site, B is bonded in a trigonal planar geometry to three O atoms. There is two shorter (1.37 Å) and one longer (1.41 Å) B–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Mg and one B atom. In the second O site, O is bonded in a trigonal planar geometry to one Mg and two B atoms. In the third O site, O is bonded in a distorted trigonal planar geometry to one Mg and two B atoms. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to two B atoms. In the fifth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the seventh O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the eighth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the ninth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the tenth O site, O is bonded in a bent 120 degrees geometry to two B atoms. In the eleventh O site, O is bonded in a single-bond geometry to one B atom. In the twelfth O site, O is bonded in a single-bond geometry to one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(IO8)2 by Materials Project

Mg(O6I)2(O2)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four hydrogen peroxide molecules and two Mg(O6I)2 clusters. In each Mg(O6I)2 cluster, Mg is bonded in a square co-planar geometry to four O atoms. There are two shorter (1.89 Å) and two longer (2.30 Å) Mg–O bond lengths. There are six inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å. In the second O site, O is bonded in a single-bond geometry to one I atom. The O–I bond length is 1.79 Å. In the third O site, O is bonded in a single-bond geometry to one I atom. The O–I bond length is 1.79 Å. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Mg and one I atom. The O–I bond length is 1.85 Å. In the fifth O site, O is bonded in a single-bond geometry to one I atom. The O–I bond length is 1.78 Å. In the sixth O site, O is bonded in a distorted bent 120 degrees geometry to one Mg and one O atom. I is bonded in a tetrahedral geometry to four O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BrO)2 by Materials Project

Mg(OBr)2 crystallizes in the monoclinic C2/m space group. The structure is one-dimensional and consists of two Mg(OBr)2 ribbons oriented in the (0, 0, 1) direction. Mg is bonded to two equivalent O and four equivalent Br atoms to form distorted edge-sharing MgBr4O2 octahedra. Both Mg–O bond lengths are 2.01 Å. There are two shorter (2.65 Å) and two longer (2.66 Å) Mg–Br bond lengths. O is bonded in a single-bond geometry to one Mg atom. Br is bonded in an L-shaped geometry to two equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Utilizing integrated neutron diffraction and elastoplastic self-consistent crystal plasticity model to quantitatively assess the strengthening mechanism in Al–12.5Ce and Al–12.5Ce–0.4Mg alloys

An integrated in-situ neutron diffraction and elastic plastic self-consistent crystal plasticity (EPSC-CP) modeling scheme is performed on a binary Al–12Ce alloy and a ternary Al–12Ce–0.4Mg alloys. Using this scheme, the constitutive parameters, i.e. elastic constants and slip system parameters of individual phases can be calibrated which can be used in microstructure-based CP models to predict materials performance. From this study, it is shown that the elastic constants of Al 11 Ce 3 intermetallics calculated from density function theory calculation in the literature are rather accurate. When applied to the EPSC-CP model, the lattice strains of both the binary and ternary alloys are correctly predicted as compared with experiments, and large lattice strain differences between Al (100) plane and Al 11 Ce 3 (010) plane are demonstrated. The slip system parameters calibrated by the scheme shows that the addition of 0.4 wt% Mg in the alloy has little influence on the critical resolved shear stress of initial dislocation glide in the Al matrix which caused plastic yield in the material. This can be explained by the very dilute Mg solute content in the Al solid solution, causing large spacing of Al–Mg lattice misfit sites and little impact on resistance of dislocation glide at initial yield. The 0.4 wt% Mg addition, on the other hand, has a large influence on the hardening term in the slip system parameters, indicating those Al–Mg misfit sites do help dislocation accumulation during the deformation. The impact of dilute Mg addition on the Al slip system parameters is also reflected in the flow behavior of the ternary alloy: little impact on the yield stress, but a large impact on working hardening and tensile strength of the materials which is consistent with the literature.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Stabilizing magnesium plating by a low-cost inorganic surface membrane for high-voltage and high-power Mg batteries

Mg batteries with halide-free electrolytes suffer from poor stability of the Mg metal anode due to electrolyte decomposition. Here, we report a low-cost zeolite membrane supported on Mg to address this challenge. It vastly reduces the population (hence decomposition) of free diglyme at the Mg/electrolyte interface, while allowing facile transport of Mg 2+ cations through the membrane. We demonstrate dendrite-free Mg plating/stripping performance in a magnesium tetrakis(hexafluoroisopropyloxy)borate/diglyme electrolyte with a 750-fold extended lifetime (over 6,000 h) and a high coulombic efficiency of ~98%. The prototype Mo 3 S 4 cathode paired with the protected Mg anode shows 91% capacity retention over 200 cycles. Importantly, this membrane protects soluble species in a high-voltage organic polymer cathode from being reduced at the anode via shuttling, achieving a full cell with a 3.5 V cutoff voltage. This results in a high specific energy density of 320 Wh kg –1 and a power density of 1,320 W kg –1 based on cathode mass.

25 ENERGY STORAGE↗