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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

The role of Ca-bridged organic matter in an alkaline soil, as revealed by multimodal chemical imaging

Mineral–organic matter (OM) studies have predominantly focused on acidic soils that are abundant in iron (Fe) oxides and aluminum (Al) oxides. We have probed mineral–OM interactions in an alkaline or calcareous soil of the Aridisols class. Unlike the role of Fe and Al, the role of Ca-minerals (particularly calcite), which are ubiquitous in alkaline soils, in OM sequestration is not well understood. Multiple recent model studies with aqueous Ca2+ or synthetic calcite and a suite of OM compounds have shown Ca-OM assemblages to be spatially correlated with calcite at the microscale. To study the chemical state of both Ca and Fe and their competing role in soil organic matter (SOM) stabilization, we performed laboratory characterization using x-ray diffraction, Mössbauer spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and scanning transmission electron microscopy, alongside synchrotron-based microscale chemical imaging using scanning transmission x-ray microscopy combined with near-edge x-ray absorption fine structure. Ca mineral–organic associations were found to be ubiquitous in this system and are likely critical for understanding SOM stabilization/degradation in alkaline soils. From our findings on mineralogy, speciation, and the nature of Ca-OM bridging, we identified differences in C and Ca chemistry based on the relative location of OM to Ca minerals. The OM near the calcite crystal was enriched in lipid and protein moieties, Ca-OM next to Fe minerals displayed a strong contribution from aromatic compounds, while on the surface of microbes, the carbonate was believed to be of microbial in origin, as also suggested by preliminary works reporting on the formation of amorphous calcite or nano-calcite. In Ca-OM admixed with carbonate, it was difficult to distinguish Ca-associated OM from amorphous calcite or nano-calcite.

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

Coupling of Ca 2+ and voltage activation in BK channels through the αB helix/voltage sensor interface

Large-conductance Ca 2+ and voltage-activated K + (BK) channels control membrane excitability in many cell types. BK channels are tetrameric. Each subunit is composed of a voltage sensor domain (VSD), a central pore-gate domain, and a large cytoplasmic domain (CTD) that contains the Ca 2+ sensors. While it is known that BK channels are activated by voltage and Ca 2+ , and that voltage and Ca 2+ activations interact, less is known about the mechanisms involved. In this work we explore these mechanisms by examining the gating contribution of an interface formed between the VSDs and the αB helices located at the top of the CTDs. Proline mutations in the αB helix greatly decreased voltage activation while having negligible effects on gating currents. Analysis with the Horrigan, Cui, and Aldrich model indicated a decreased coupling between voltage sensors and pore gate. Proline mutations decreased Ca 2+ activation for both Ca 2+ bowl and RCK1 Ca 2+ sites, suggesting that both high-affinity Ca 2+ sites transduce their effect, at least in part, through the αB helix. Mg 2+ activation also decreased. The crystal structure of the CTD with proline mutation L390P showed a flattening of the first helical turn in the αB helix compared to wild type, without other notable differences in the CTD, indicating that structural changes from the mutation were confined to the αB helix. These findings indicate that an intact αB helix/VSD interface is required for effective coupling of Ca 2+ binding and voltage depolarization to pore opening and that shared Ca 2+ and voltage transduction pathways involving the αB helix may be involved.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

The Timing of Potential Last Nucleosynthetic Injections into the Protosolar Molecular Cloud Inferred from 41 Ca– 26 Al Systematics of Bulk CAIs

Short-lived radionuclides (SLRs) provide important information about the chronology of the early solar system. Among them, 41 Ca, due to its decay to 41 K with a half-life of only 0.1 Ma, is particularly valuable in constraining the timescales and origins of both SLRs and the formation of the oldest solar system materials, the Ca–Al-rich inclusions (CAIs). The initial abundance of 41Ca in the solar system, expressed as the ( 41 Ca/ 40 Ca)I ratio, is the key to unveiling the origin of this nuclide. Here, we report a new solar system ( 41 Ca/ 40 Ca)I ratio of 2.0 × 10 −8 derived from the K isotope compositions of two CAIs. This new ratio is about four times higher than the previous value inferred from a mineral isochron. Such a high ( 41 Ca/ 40 Ca)I ratio in the CAIs exceeds that expected for the protosolar molecular cloud by ∼1000×, implying very late injection of the 41 Ca (and possibly other SLRs) into the protosolar molecular cloud. The correlated enrichments of 41 Ca and 26 Al in the bulk CAI samples hint at a common stellar origin of both SLRs. The injection time estimated from our new data depends on the stellar source—it ranges from 0.6 Ma for a Wolf–Rayet wind to 1.0 Ma for a TP-AGB star ejecta.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on Ca(Al4Co)2 by Materials Project

CaCo2Al8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ca is bonded in a 11-coordinate geometry to thirteen Al atoms. There are a spread of Ca–Al bond distances ranging from 3.11–3.36 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Co–Al bond distances ranging from 2.35–2.56 Å. In the second Co site, Co is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Co–Al bond distances ranging from 2.34–2.56 Å. There are nine inequivalent Al sites. In the first Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ca, two equivalent Co, and three Al atoms. There are two shorter (2.69 Å) and one longer (2.75 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a distorted linear geometry to two equivalent Ca, two Co, and six Al atoms. There are a spread of Al–Al bond distances ranging from 2.79–2.84 Å. In the third Al site, Al is bonded in a 3-coordinate geometry to three Co and two equivalent Al atoms. Both Al–Al bond lengths are 3.00 Å. In the fourth Al site, Al is bonded in a 4-coordinate geometry to two equivalent Ca, two equivalent Co, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–3.03 Å. In the fifth Al site, Al is bonded in a distorted linear geometry to two equivalent Ca, two equivalent Co, and eight Al atoms. All Al–Al bond lengths are 2.89 Å. In the sixth Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ca, two equivalent Co, and six Al atoms. There are one shorter (2.67 Å) and one longer (2.75 Å) Al–Al bond lengths. In the seventh Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ca, two equivalent Co, and eight Al atoms. The Al–Al bond length is 2.68 Å. In the eighth Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ca, two equivalent Co, and five Al atoms. The Al–Al bond length is 2.64 Å. In the ninth Al site, Al is bonded in a 12-coordinate geometry to four equivalent Co and four Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(AgO2)2 by Materials Project

Ca(AgO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 52–63°. There are a spread of Ca–O bond distances ranging from 2.24–2.31 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three CaO4 tetrahedra, corners with three AgO4 tetrahedra, and edges with six AgO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.37 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Ca–O bond distances ranging from 2.24–2.33 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four AgO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five AgO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.38 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six AgO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent AgO6 octahedra. There are four shorter (2.30 Å) and two longer (2.36 Å) Ca–O bond lengths. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six AgO4 tetrahedra, edges with two CaO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.43 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five AgO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five AgO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.36 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six AgO4 tetrahedra, edges with two CaO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.39 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 three CaO4 tetrahedra, corners with three AgO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.10–2.37 Å. In the second Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent AgO4 tetrahedra, edges with two CaO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.10–2.37 Å. In the third Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six CaO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Ag–O bond distances ranging from 2.19–2.27 Å. In the fourth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four AgO4 tetrahedra, edges with three CaO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.04–2.22 Å. In the fifth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 54–66°. There are a spread of Ag–O bond distances ranging from 2.10–2.28 Å. In the sixth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six CaO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are one shorter (2.14 Å) and three longer (2.19 Å) Ag–O bond lengths. 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 CaO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.19 Å. In the eighth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six CaO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 53–66°. There are a spread of Ag–O bond distances ranging from 2.18–2.23 Å. In the ninth Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five AgO4 tetrahedra, edges with three CaO6 octahedra, and edges with three AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.06–2.33 Å. In the tenth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with six CaO6 octahedra and corners with six AgO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Ag–O bond distances ranging from 2.19–2.35 Å. In the eleventh Ag3+ site, Ag3+ is bonded to six O2- atoms to form AgO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent AgO4 tetrahedra, edges with two CaO6 octahedra, and edges with four AgO6 octahedra. There are a spread of Ag–O bond distances ranging from 2.11–2.20 Å. In the twelfth Ag3+ site, Ag3+ is bonded to four O2- atoms to form AgO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine AgO6 octahedra. The corner-sharing octahedra tilt angles range from 51–68°. There are a spread of Ag–O bond distances ranging from 2.16–2.35 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Ag3+ atoms to form distorted OCa2Ag2 tetrahedra that share corners with two OCa2Ag2 tetrahedra, corners with seven OCaAg3 trigonal pyramids, an edgeedge with one OCa2Ag2 tetrahedra, and an edgeedge with one OCa2Ag2 trigonal pyramid. In the second O2- site, O2- is bonded to two Ca2+ and two equivalent Ag3+ atoms to form distorted OCa2Ag2 trigonal pyramids that share corners with two equivalent OCa2Ag2 tetrahedra, corners with seven OCaAg3 trigonal pyramids, and edges with two equivalent OCa2Ag2 tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ag3+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two Ag3+ atoms to form distorted OCa2Ag2 tetrahedra that share a cornercorner with one OCa2Ag2 tetrahedra, corners with five OCaAg3 trigonal pyramids, and an edgeedge with one OCa2Ag2 tetrahedra. In the sixth O2- site, O2- is bonded to one Ca2+ and three Ag3+ atoms to form distorted OCaAg3 trigonal pyramids that share corners with five OCa2Ag2 tetrahedra, corners with four OCaAg3 trigonal pyramids, and edges with two OCaAg3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Ag3+ atoms to form distorted OCaAg3 trigonal pyramids that share corners with four equivalent OCa2Ag2 tetrahedra, corners with five OCaAg3 trigonal pyramids, and edges with two equivalent OCaAg3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Ag3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Ag3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the fourteenth O2- site, O2- is bonded to one Ca2+ and three Ag3+ atoms to form distorted OCaAg3 trigonal pyramids that share corners with four equivalent OCa2Ag2 tetrahedra and corners with two equivalent OCaAg3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ag3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Ag3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Ag3+ atoms to form distorted OCa2Ag2 tetrahedra that share corners with two equivalent OCa2Ag2 tetrahedra and corners with seven OCaAg3 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ag3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ag3+ atoms. In the twenty-third O2- site, O2- is bonded to one Ca2+ and three Ag3+ atoms to form distorted OCaAg3 trigonal pyramids that share corners with four OCa2Ag2 tetrahedra, corners with two OCaAg3 trigonal pyramids, and edges with two OCaAg3 trigonal pyramids. In the twenty-fourth O2- site, O2- is bonded to one Ca2+ and three Ag3+ atoms to form distorted OCaAg3 trigonal pyramids that share corners with three equivalent OCa2Ag2 tetrahedra and edges with two equivalent OCaAg3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(SnO2)2 by Materials Project

Ca(SnO2)2 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–65°. There are a spread of Ca–O bond distances ranging from 2.26–2.56 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three CaO4 tetrahedra and edges with four equivalent SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.41 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–67°. There are a spread of Ca–O bond distances ranging from 2.25–2.52 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with three SnO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.41 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with five SnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.43 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with six SnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.41–2.47 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, a cornercorner with one SnO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with four equivalent SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.32–2.40 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three equivalent SnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four SnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.37–2.47 Å. There are twelve inequivalent Sn3+ sites. In the first Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with three CaO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with two equivalent SnO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.07–2.19 Å. In the second Sn3+ site, Sn3+ is bonded in a 6-coordinate geometry to three O2- atoms. There are two shorter (2.24 Å) and one longer (2.32 Å) Sn–O bond lengths. In the third Sn3+ site, Sn3+ is bonded to four O2- atoms to form distorted SnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–74°. There are a spread of Sn–O bond distances ranging from 2.14–2.80 Å. In the fourth Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with three SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with three CaO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.08–2.22 Å. In the fifth Sn3+ site, Sn3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are two shorter (2.09 Å) and one longer (2.32 Å) Sn–O bond lengths. In the sixth Sn3+ site, Sn3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are two shorter (2.13 Å) and one longer (2.59 Å) Sn–O bond lengths. In the seventh Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with five SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.10–2.15 Å. In the eighth Sn3+ site, Sn3+ is bonded to four O2- atoms to form distorted SnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–74°. There are a spread of Sn–O bond distances ranging from 2.15–2.74 Å. In the ninth Sn3+ site, Sn3+ is bonded to six O2- atoms to form SnO6 octahedra that share a cornercorner with one CaO4 tetrahedra, a cornercorner with one SnO4 tetrahedra, edges with two equivalent SnO6 octahedra, and edges with three CaO6 octahedra. There are a spread of Sn–O bond distances ranging from 2.10–2.19 Å. In the tenth Sn3+ site, Sn3+ is bonded to four O2- atoms to form distorted SnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six SnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–75°. There are a spread of Sn–O bond distances ranging from 2.15–2.76 Å. In the eleventh Sn3+ site, Sn3+ is bonded in a 6-coordinate geometry to three O2- atoms. There are two shorter (2.24 Å) and one longer (2.28 Å) Sn–O bond lengths. In the twelfth Sn3+ site, Sn3+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are two shorter (2.09 Å) and one longer (2.34 Å) Sn–O bond lengths. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Sn3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Sn2 tetrahedra. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two equivalent Sn3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Sn3+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to three Sn3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Sn3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two Sn3+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and three Sn3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Sn3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Sn3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Sn3+ atoms. In the eleventh O2- site, O2- is bonded to one Ca2+ and three Sn3+ atoms to form distorted OCaSn3 trigonal pyramids that share corners with three OCaSn3 tetrahedra and edges with two equivalent OCa2Sn2 tetrahedra. In the twelfth O2- site, O2- is bonded to two Ca2+ and two Sn3+ atoms to form distorted OCa2Sn2 tetrahedra that share corners with two OCaSn3 tetrahedra, a cornercorner with one OCaSn3 trigonal pyramid, an edgeedge with one OCa2Sn2 tetrahedra, and an edgeedge with one OCaSn3 trigonal pyramid. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Sn3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Sn3+ atoms. In the fifteenth O2- site, O2- is bonded to one Ca2+ and three Sn3+ atoms to form distorted corner-sharing OCaSn3 tetrahedra. In the sixteenth O2- site, O2- is bonded to one Ca2+ and three Sn3+ atoms to form distorted OCaSn3 tetrahedra that share corners with seven OCaSn3 tetrahedra and edges with two equivalent OCa2Sn2 tetrahedra. In the seventeenth O2- site, O2- is bonded to two Ca2+ and two Sn3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Sn2 tetrahedra. In the eighteenth O2- site, O2- is bonded to two Ca2+ and two Sn3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Sn2 tetrahedra. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two equivalent Sn3+ atoms. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Sn3+ atoms. In the twenty-first O2- site, O2- is bonded to one Ca2+ and three Sn3+ atoms to form distorted OCaSn3 tetrahedra that share corners with five OCaSn3 tetrahedra and edges with two equivalent OCa2Sn2 tetrahedra. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to three Sn3+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two Sn3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Sn3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(NiO2)2 by Materials Project

Ca(NiO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–75°. There are a spread of Ca–O bond distances ranging from 2.15–2.26 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three CaO4 tetrahedra, corners with three NiO4 tetrahedra, and edges with six NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.27 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 54–72°. There are a spread of Ca–O bond distances ranging from 2.14–2.26 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four NiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.22–2.30 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.23–2.29 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.33 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five NiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.27 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.31 Å. There are twelve inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three CaO4 tetrahedra, corners with three NiO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.88–2.24 Å. In the second Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.87–2.18 Å. In the third Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of Ni–O bond distances ranging from 1.87–1.90 Å. In the fourth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four NiO4 tetrahedra, edges with three CaO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.87–2.15 Å. In the fifth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–65°. There are a spread of Ni–O bond distances ranging from 1.90–2.01 Å. In the sixth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 48–65°. There are a spread of Ni–O bond distances ranging from 1.84–1.92 Å. In the seventh Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six NiO4 tetrahedra, edges with two equivalent NiO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.92–2.19 Å. In the eighth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 51–68°. There are a spread of Ni–O bond distances ranging from 1.90–2.09 Å. In the ninth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five NiO4 tetrahedra, edges with three CaO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.90–2.31 Å. In the tenth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 50–69°. There are a spread of Ni–O bond distances ranging from 1.89–2.08 Å. In the eleventh Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.85–1.94 Å. In the twelfth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 46–68°. There are a spread of Ni–O bond distances ranging from 1.99–2.21 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Ni3+ atoms to form distorted OCa2Ni2 tetrahedra that share corners with two OCa2Ni2 tetrahedra, corners with five OCaNi3 trigonal pyramids, an edgeedge with one OCa2Ni2 tetrahedra, and an edgeedge with one OCa2Ni2 trigonal pyramid. In the second O2- site, O2- is bonded to two Ca2+ and two equivalent Ni3+ atoms to form distorted OCa2Ni2 trigonal pyramids that share corners with two equivalent OCa2Ni2 tetrahedra, corners with eight OCaNi3 trigonal pyramids, and edges with two equivalent OCa2Ni2 tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ni3+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two Ni3+ atoms to form distorted OCa2Ni2 tetrahedra that share a cornercorner with one OCa2Ni2 tetrahedra, corners with five OCa2Ni2 trigonal pyramids, an edgeedge with one OCa2Ni2 tetrahedra, and an edgeedge with one OCaNi3 trigonal pyramid. In the sixth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with five OCa2Ni2 tetrahedra, corners with four OCa2Ni2 trigonal pyramids, and edges with two OCaNi3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four equivalent OCa2Ni2 tetrahedra, corners with three equivalent OCa2Ni2 trigonal pyramids, and edges with two equivalent OCaNi3 trigonal pyramids. In the ninth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form a mixture of distorted edge and corner-sharing OCaNi3 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the eleventh O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with two equivalent OCa2Ni2 tetrahedra and corners with two equivalent OCaNi3 trigonal pyramids. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Ni3+ atoms to form distorted corner-sharing OCa2Ni2 tetrahedra. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ni3+ atoms. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CuO2)2 by Materials Project

Ca(CuO2)2 is Hausmannite-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with seven CuO6 octahedra. The corner-sharing octahedra tilt angles range from 39–75°. There are three shorter (2.19 Å) and one longer (2.26 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.25–2.35 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with nine CuO6 octahedra. The corner-sharing octahedra tilt angles range from 57–72°. There are a spread of Ca–O bond distances ranging from 2.19–2.30 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with two CuO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five CuO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.34 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three CuO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent CuO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.32 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent CuO4 tetrahedra, edges with two CaO6 octahedra, and edges with four CuO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.35 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with four CuO4 tetrahedra, an edgeedge with one CaO6 octahedra, and an edgeedge with one CuO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.21–2.38 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three equivalent CuO4 tetrahedra, edges with two CaO6 octahedra, and edges with two equivalent CuO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.32 Å. There are twelve inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with three CaO4 tetrahedra, corners with three CuO4 tetrahedra, and edges with four CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.84–2.46 Å. In the second Cu3+ site, Cu3+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent CuO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with four CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.88–2.35 Å. In the third Cu3+ site, Cu3+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with six CaO6 octahedra and corners with six CuO6 octahedra. The corner-sharing octahedra tilt angles range from 45–64°. There are a spread of Cu–O bond distances ranging from 1.85–1.94 Å. In the fourth Cu3+ site, Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with two CuO4 tetrahedra, edges with three CaO6 octahedra, and edges with three CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.88–2.38 Å. In the fifth Cu3+ site, Cu3+ is bonded to four O2- atoms to form CuO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with nine CuO6 octahedra. The corner-sharing octahedra tilt angles range from 47–60°. There are a spread of Cu–O bond distances ranging from 1.83–2.06 Å. In the sixth Cu3+ site, Cu3+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with two equivalent CuO6 octahedra and corners with six CaO6 octahedra. The corner-sharing octahedra tilt angles range from 31–69°. There are a spread of Cu–O bond distances ranging from 1.80–2.10 Å. In the seventh Cu3+ site, Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with three CuO4 tetrahedra, edges with two equivalent CuO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.88–2.28 Å. In the eighth Cu3+ site, Cu3+ is bonded in a trigonal planar geometry to three O2- atoms. All Cu–O bond lengths are 1.86 Å. In the ninth Cu3+ site, Cu3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.83–1.92 Å. In the tenth Cu3+ site, Cu3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.78 Å) and two longer (1.85 Å) Cu–O bond length. In the eleventh Cu3+ site, Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent CuO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with two equivalent CuO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.91–2.04 Å. In the twelfth Cu3+ site, Cu3+ is bonded to four O2- atoms to form CuO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with five CuO6 octahedra. The corner-sharing octahedra tilt angles range from 22–68°. There are a spread of Cu–O bond distances ranging from 1.89–2.17 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Cu3+ atoms to form distorted OCa2Cu2 tetrahedra that share corners with two OCa2Cu2 tetrahedra, corners with seven OCaCu3 trigonal pyramids, an edgeedge with one OCa2Cu2 tetrahedra, and an edgeedge with one OCa2Cu2 trigonal pyramid. In the second O2- site, O2- is bonded to two Ca2+ and two equivalent Cu3+ atoms to form distorted OCa2Cu2 trigonal pyramids that share corners with two equivalent OCa2Cu2 tetrahedra, corners with seven OCaCu3 trigonal pyramids, and edges with two equivalent OCa2Cu2 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Cu3+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to four Cu3+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two Cu3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Cu2 tetrahedra. In the sixth O2- site, O2- is bonded to one Ca2+ and three Cu3+ atoms to form distorted OCaCu3 trigonal pyramids that share corners with five OCa2Cu2 tetrahedra, corners with three OCa2Cu2 trigonal pyramids, and edges with two OCaCu3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Cu3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Cu3+ atoms to form distorted OCaCu3 trigonal pyramids that share corners with four equivalent OCa2Cu2 tetrahedra, corners with five OCaCu3 trigonal pyramids, and edges with two equivalent OCaCu3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Cu3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Cu3+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Cu3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Cu3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to one Ca2+ and three Cu3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Cu3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Cu3+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Cu3+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Cu3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Cu3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Cu3+ atoms to form OCa2Cu2 tetrahedra that share corners with two equivalent OCa2Cu2 tetrahedra and corners with four equivalent OCaCu3 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Cu3+ atoms. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Cu3+ atom. In the twenty-second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cu3+ atoms. In the twenty-third O2- site, O2- is bonded to one Ca2+ and three Cu3+ atoms to form distorted OCaCu3 trigonal pyramids that share corners with four OCa2Cu2 tetrahedra, corners with two OCaCu3 trigonal pyramids, and an edgeedge with one OCaCu3 trigonal pyramid. In the twenty-fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Cu3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(MoO2)2 by Materials Project

Ca(MoO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 55–71°. There are a spread of Ca–O bond distances ranging from 2.21–2.32 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three CaO4 tetrahedra, corners with three MoO4 tetrahedra, and edges with six MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.38 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–70°. There are a spread of Ca–O bond distances ranging from 2.20–2.32 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.29–2.37 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.35 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.38 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.38 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.37 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 three CaO4 tetrahedra, corners with three MoO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.12–2.24 Å. In the second Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.12–2.25 Å. In the third Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 51–72°. There are a spread of Mo–O bond distances ranging from 2.05–2.23 Å. In the fourth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.13–2.21 Å. In the fifth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–71°. There are a spread of Mo–O bond distances ranging from 2.06–2.33 Å. In the sixth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 51–73°. There are a spread of Mo–O bond distances ranging from 2.05–2.19 Å. In the seventh Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with six MoO4 tetrahedra, edges with two equivalent MoO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.19–2.21 Å. In the eighth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 52–72°. There are a spread of Mo–O bond distances ranging from 2.04–2.20 Å. In the ninth Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.15–2.23 Å. In the tenth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MoO6 octahedra. The corner-sharing octahedra tilt angles range from 52–72°. There are a spread of Mo–O bond distances ranging from 2.04–2.23 Å. In the eleventh Mo3+ site, Mo3+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent MoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MoO6 octahedra. There are a spread of Mo–O bond distances ranging from 2.13–2.23 Å. In the twelfth Mo3+ site, Mo3+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–69°. There are a spread of Mo–O bond distances ranging from 2.05–2.45 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 Ca2+ and two Mo3+ atoms. In the second O2- site, O2- is bonded to two Ca2+ and two equivalent Mo3+ atoms to form distorted corner-sharing OCa2Mo2 trigonal pyramids. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the fourth O2- site, O2- is bonded to four Mo3+ atoms to form distorted corner-sharing OMo4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the ninth O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form distorted corner-sharing OCaMo3 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the eleventh O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form a mixture of edge and corner-sharing OCaMo3 trigonal pyramids. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the fourteenth O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form OCaMo3 trigonal pyramids that share corners with three OMo4 trigonal pyramids and an edgeedge with one OCaMo3 trigonal pyramid. In the fifteenth O2- site, O2- is bonded to one Ca2+ and three Mo3+ atoms to form corner-sharing OCaMo3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mo3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Mo3+ atoms to form distorted corner-sharing OCa2Mo2 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twenty-second O2- site, O2- is bonded to four Mo3+ atoms to form distorted corner-sharing OMo4 trigonal pyramids. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mo3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(WO2)2 by Materials Project

Ca(WO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 58–61°. There are a spread of Ca–O bond distances ranging from 2.20–2.32 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with three CaO4 tetrahedra, corners with three WO4 tetrahedra, and edges with six WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.36 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 56–65°. There are a spread of Ca–O bond distances ranging from 2.22–2.32 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four WO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.29–2.44 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.35–2.39 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.42 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five WO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.38 Å. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.41 Å. There are twelve inequivalent W3+ sites. In the first W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three CaO4 tetrahedra, corners with three WO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.26 Å. In the second W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.29 Å. In the third W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 49–67°. There are a spread of W–O bond distances ranging from 2.02–2.07 Å. In the fourth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four WO4 tetrahedra, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.26 Å. In the fifth W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 52–66°. There are a spread of W–O bond distances ranging from 2.08–2.16 Å. In the sixth W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 52–73°. There are a spread of W–O bond distances ranging from 2.14–2.19 Å. In the seventh W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with six WO4 tetrahedra, edges with two equivalent WO6 octahedra, and edges with four CaO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.24 Å. In the eighth W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 53–70°. There are a spread of W–O bond distances ranging from 2.12–2.20 Å. In the ninth W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five WO4 tetrahedra, edges with three CaO6 octahedra, and edges with three WO6 octahedra. There are a spread of W–O bond distances ranging from 2.15–2.24 Å. In the tenth W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with six CaO6 octahedra and corners with six WO6 octahedra. The corner-sharing octahedra tilt angles range from 48–70°. There are one shorter (2.04 Å) and three longer (2.09 Å) W–O bond lengths. In the eleventh W3+ site, W3+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent WO4 tetrahedra, edges with two CaO6 octahedra, and edges with four WO6 octahedra. There are a spread of W–O bond distances ranging from 2.14–2.23 Å. In the twelfth W3+ site, W3+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine WO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of W–O bond distances ranging from 2.07–2.38 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 Ca2+ and two W3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two equivalent W3+ atoms. In the third O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form distorted OCaW3 trigonal pyramids that share a cornercorner with one OW4 tetrahedra and a cornercorner with one OCa2W2 trigonal pyramid. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four W3+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two W3+ atoms to form distorted OCa2W2 trigonal pyramids that share a cornercorner with one OCaW3 tetrahedra, a cornercorner with one OCa2W2 trigonal pyramid, an edgeedge with one OCaW3 tetrahedra, and an edgeedge with one OCa2W2 trigonal pyramid. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the ninth O2- site, O2- is bonded to one Ca2+ and three W3+ atoms to form a mixture of distorted corner and edge-sharing OCaW3 tetrahedra. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the thirteenth O2- site, O2- is bonded in a trigonal pyramidal geometry to one Ca2+ and three W3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two W3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent W3+ atoms to form distorted OCa2W2 trigonal pyramids that share corners with two equivalent OW4 tetrahedra and a cornercorner with one OCaW3 trigonal pyramid. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twenty-second O2- site, O2- is bonded to four W3+ atoms to form distorted corner-sharing OW4 tetrahedra. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three W3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO5)2 by Materials Project

Ca(BO4)2O2 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of four oxygen molecules and two Ca(BO4)2 sheets oriented in the (1, 0, 0) direction. In each Ca(BO4)2 sheet, Ca is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of Ca–O bond distances ranging from 2.39–2.80 Å. B is bonded in a tetrahedral geometry to four O atoms. There are a spread of B–O bond distances ranging from 1.41–1.47 Å. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to two equivalent Ca and one B atom. In the second O site, O is bonded in a distorted single-bond geometry to one Ca and one B atom. In the third O site, O is bonded in a distorted single-bond geometry to one Ca and one B atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Ca and one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(InCu)6 by Materials Project

Ca(CuIn)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to twelve Cu and eight In atoms. There are four shorter (3.54 Å) and eight longer (3.56 Å) Ca–Cu bond lengths. There are a spread of Ca–In bond distances ranging from 3.12–3.27 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to two equivalent Ca, four Cu, and six In atoms to form a mixture of distorted face, edge, and corner-sharing CuCa2In6Cu4 cuboctahedra. There are two shorter (2.71 Å) and two longer (2.78 Å) Cu–Cu bond lengths. There are two shorter (2.76 Å) and four longer (2.83 Å) Cu–In bond lengths. In the second Cu site, Cu is bonded to two equivalent Ca, four equivalent Cu, and six In atoms to form a mixture of distorted face, edge, and corner-sharing CuCa2In6Cu4 cuboctahedra. There are a spread of Cu–In bond distances ranging from 2.77–2.94 Å. There are three inequivalent In sites. In the first In site, In is bonded in a 8-coordinate geometry to one Ca, six Cu, and one In atom. The In–In bond length is 2.98 Å. In the second In site, In is bonded in a 10-coordinate geometry to one Ca and six Cu atoms. In the third In site, In is bonded in a 8-coordinate geometry to two equivalent Ca and six Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO2)3 by Materials Project

Ca(BO2)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Ca–O bond distances ranging from 2.42–2.68 Å. There are three 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 1.45–1.49 Å. In the second B site, B is bonded to four O atoms to form corner-sharing BO4 tetrahedra. There is one shorter (1.47 Å) and three longer (1.48 Å) B–O bond length. In the third 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. There are six inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the third O site, O is bonded in a distorted single-bond geometry to two equivalent Ca and one B atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to one Ca and two B atoms. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent Ca and two B atoms. In the sixth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(MnAl3)3 by Materials Project

Ca(MnAl3)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca is bonded in a 4-coordinate geometry to six Mn and fourteen Al atoms. There are two shorter (3.41 Å) and four longer (3.44 Å) Ca–Mn bond lengths. There are a spread of Ca–Al bond distances ranging from 3.05–3.37 Å. There are two inequivalent Mn sites. In the first Mn site, Mn is bonded to two equivalent Ca and ten Al atoms to form distorted MnCa2Al10 cuboctahedra that share corners with two equivalent AlCa2Mn2Al8 cuboctahedra, corners with eight MnCa2Al10 cuboctahedra, edges with four equivalent MnCa2Mn2Al8 cuboctahedra, faces with two equivalent AlCa2Mn2Al8 cuboctahedra, and faces with four equivalent MnCa2Mn2Al8 cuboctahedra. There are a spread of Mn–Al bond distances ranging from 2.58–2.76 Å. In the second Mn site, Mn is bonded to two equivalent Ca, two equivalent Mn, and eight Al atoms to form distorted MnCa2Mn2Al8 cuboctahedra that share corners with two equivalent AlCa2Mn2Al8 cuboctahedra, corners with eight MnCa2Al10 cuboctahedra, edges with two equivalent MnCa2Al10 cuboctahedra, edges with two equivalent AlCa2Mn2Al8 cuboctahedra, faces with two equivalent AlCa2Mn2Al8 cuboctahedra, and faces with four MnCa2Al10 cuboctahedra. Both Mn–Mn bond lengths are 2.58 Å. There are a spread of Mn–Al bond distances ranging from 2.53–2.68 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ca, three Mn, and seven Al atoms. There are a spread of Al–Al bond distances ranging from 2.67–2.96 Å. In the second Al site, Al is bonded in a 10-coordinate geometry to one Ca, three Mn, and six Al atoms. There are one shorter (2.78 Å) and one longer (2.83 Å) Al–Al bond lengths. In the third Al site, Al is bonded to two equivalent Ca, two equivalent Mn, and eight Al atoms to form distorted AlCa2Mn2Al8 cuboctahedra that share corners with four equivalent AlCa2Mn2Al8 cuboctahedra, corners with six MnCa2Al10 cuboctahedra, edges with four equivalent MnCa2Mn2Al8 cuboctahedra, and faces with six MnCa2Al10 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(CdAu2)2 by Materials Project

Ca(Au2Cd)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ca is bonded to twelve Au atoms to form a mixture of distorted edge and face-sharing CaAu12 cuboctahedra. There are four shorter (3.11 Å) and eight longer (3.45 Å) Ca–Au bond lengths. There are six inequivalent Au sites. In the first Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. There are two shorter (2.85 Å) and two longer (3.01 Å) Au–Au bond lengths. All Au–Cd bond lengths are 2.97 Å. In the second Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. Both Au–Au bond lengths are 2.85 Å. All Au–Cd bond lengths are 2.97 Å. In the third Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. There are one shorter (2.85 Å) and two longer (3.01 Å) Au–Au bond lengths. All Au–Cd bond lengths are 2.97 Å. In the fourth Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. The Au–Au bond length is 2.85 Å. All Au–Cd bond lengths are 2.97 Å. In the fifth Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. There are one shorter (2.85 Å) and two longer (3.01 Å) Au–Au bond lengths. All Au–Cd bond lengths are 2.97 Å. In the sixth Au site, Au is bonded in a 11-coordinate geometry to three equivalent Ca, four Au, and four equivalent Cd atoms. All Au–Cd bond lengths are 2.97 Å. Cd is bonded in a 10-coordinate geometry to eight Au and two equivalent Cd atoms. Both Cd–Cd bond lengths are 2.81 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(BO2)3 by Materials Project

Ca(BO2)3 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. Ca is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.67 Å. There are three inequivalent B sites. In the first 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 second 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 1.45–1.51 Å. In the third 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 1.44–1.51 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Ca and two B atoms. In the second O site, O is bonded in a 1-coordinate geometry to two equivalent Ca and one B atom. In the third O site, O is bonded in a distorted trigonal planar geometry to one Ca and two B atoms. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two B atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to one Ca and two B atoms. In the sixth O site, O is bonded in a 2-coordinate geometry to one Ca and two B atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Structure and thermodynamics of calcium rare earth silicate oxyapatites, Ca 2 RE 8 (SiO 4 ) 6 O 2 (RE = Pr, Tb, Ho, Tm)

Calcium rare earth silicate oxyapatites, (Ca 2 RE 8 (SiO 4 ) 6 O 2 ), are of interest as components of glass-ceramic nuclear waste forms. To assess their long-term behavior in a geologic repository, it is essential to determine their structure and thermodynamic stability at relevant conditions. Here, in this work, we performed detailed structural and thermodynamic investigations on Ca 2 Pr 8 (SiO 4 ) 6 O 2 , Ca 2 Tb 8 (SiO 4 ) 6 O 2 , Ca 2 Ho 8 (SiO 4 ) 6 O 2 , and Ca 2 Tm 8 (SiO 4 ) 6 O 2 by high energy synchrotron powder X-ray diffraction combined with Rietveld analysis and high temperature oxide melt drop solution calorimetry. Enthalpies of formation from constituent oxides (ΔH f,ox ) were determined to be -765.1 ± 22.8 kJ/mol for Ca 2 Pr 8 (SiO 4 ) 6 O 2 ; -638.9 ± 20.5 kJ/mol for Ca 2 Tb 8 (SiO 4 ) 6 O 2 ; -643.3 ± 10.3 kJ/mol for Ca 2 Ho 8 (SiO 4 ) 6 O 2 ; and -403.2 ± 5.1 kJ/mol for Ca 2 Tm 8 (SiO 4 ) 6 O 2 . These thermodynamic parameters were used in assessing the thermochemical stability of these phases in the presence of water vapor from room temperature to 600 K, as encountered in the subsurface environments of a geological repository.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Exploring Ca–Ce–M–O (M = 3d Transition Metal) Oxide Perovskites for Solar Thermochemical Applications

Solar thermochemical (STC) processes hold promise as efficient ways to generate renewable fuels, fuel precursors, or chemical feedstocks using concentrated sunlight. Specifically, one actively researched approach is the two-step STC cycle, which uses a redox-active, off-stoichiometric, transition-metal oxide material to split water and/or CO 2 , generating H 2 and/or CO, respectively, or syngas (a combination of H 2 and CO). Identifying novel metal oxides that yield larger reduction extents (practically achievable off-stoichiometries) than the state-of-the-art CeO 2 is critical. Here, we explore the chemical space of Ca–Ce–M–O (M = 3d transition metal, except Cu and Zn) metal oxide perovskites, with Ca and/or Ce occupying the A site and M occupying the B site within an ABO 3 framework, as potential STC candidates. We use density functional theory (DFT)-based calculations and systematically evaluate the oxygen vacancy (VaO) formation energy (≈ enthalpy of reduction in an STC cycle), electronic properties, thermodynamic stability of CaMO 3 , CeMO 3 , and Ca 0.5 Ce 0.5 MO 3 perovskites, and the VaO formation energy within Ca 0.5 Ce 0.5 Ti 0.5 Mg 0.5 O 3 perovskite. We consider only Ca and/or Ce on the A site because of their similar size and the potential redox activity of Ce 4+ . If both Ce and M exhibit simultaneous reduction with Va O formation, the resulting perovskite could exhibit a larger entropy of reduction than a single cation reduction. The increased entropy produces increased reduction for fixed temperature, partial pressure of oxygen, and reduction enthalpy, and therefore increased STC efficiency. Importantly, we identify Ca 0.5 Ce 0.5 MnO 3 , Ca 0.5 Ce 0.5 FeO 3 , and Ca 0.5 Ce 0.5 VO 3 to be promising candidates based on their Va O formation energy and thermodynamic (meta)stability. Moreover, based on our calculated on-site magnetic moments, electron density of states, and electron density differences between pristine and defective structures, we find Ca 0.5 Ce 0.5 MnO 3 to exhibit simultaneous reduction of both Ce 4+ (A-site) and Mn 3+ (B-site), highlighting a particularly promising candidate for STC applications with a predicted higher entropy of reduction than CeO 2 . Lastly, we extract metrics that govern the trends in Va O formation energies, such as standard reduction potentials, and provide pointers for further experimental and theoretical studies, which will enable the design of improved materials for the STC cycle.

14 SOLAR ENERGY↗