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DOE OSTI2020

Materials Data on Zn(FeO2)2 by Materials Project

ZnFe2O4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are eight inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–64°. There are two shorter (1.94 Å) and four longer (2.08 Å) Fe–O bond lengths. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Fe–O bond distances ranging from 1.93–2.03 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Fe–O bond distances ranging from 1.93–2.02 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of Fe–O bond distances ranging from 1.94–2.14 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–60°. There are a spread of Fe–O bond distances ranging from 1.94–2.13 Å. In the sixth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–60°. There are a spread of Fe–O bond distances ranging from 1.93–2.12 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Fe–O bond distances ranging from 1.99–2.06 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–62°. There are a spread of Fe–O bond distances ranging from 1.94–2.01 Å. There are four inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Zn–O bond distances ranging from 2.18–2.70 Å. In the second Zn2+ site, Zn2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zn–O bond distances ranging from 2.22–2.63 Å. In the third Zn2+ site, Zn2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zn–O bond distances ranging from 2.22–2.60 Å. In the fourth Zn2+ site, Zn2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Zn–O bond distances ranging from 2.20–2.35 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms. In the third O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing OZn2Fe3 trigonal bipyramids. In the fourth O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing OZn2Fe3 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two Zn2+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Fe3+ and two Zn2+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Fe3+ and one Zn2+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Fe3+ and two Zn2+ atoms. In the ninth O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form distorted edge-sharing OZn2Fe3 trigonal bipyramids. In the tenth O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form distorted edge-sharing OZn2Fe3 trigonal bipyramids. In the eleventh O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing OZn2Fe3 trigonal bipyramids. In the twelfth O2- site, O2- is bonded to three Fe3+ and two equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing OZn2Fe3 trigonal bipyramids. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms. In the fourteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms. In the fifteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms. In the sixteenth O2- site, O2- is bonded in a 5-coordinate geometry to three Fe3+ and two equivalent Zn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(FeO2)2 by Materials Project

CaFe2O4 is Spinel structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedra tilt angles range from 60–61°. All Ca–O bond lengths are 2.20 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. There are four shorter (2.08 Å) and two longer (2.09 Å) Fe–O bond lengths. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CaO4 tetrahedra and edges with six FeO6 octahedra. All Fe–O bond lengths are 2.08 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the second O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(FeO2)2 by Materials Project

MgFe2O4 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.23–2.60 Å. In the second Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.22–2.53 Å. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–63°. There are a spread of Fe–O bond distances ranging from 1.92–2.02 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–65°. There are a spread of Fe–O bond distances ranging from 1.96–2.09 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–63°. There are a spread of Fe–O bond distances ranging from 1.98–2.10 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–65°. There are a spread of Fe–O bond distances ranging from 1.98–2.09 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Fe3 trigonal bipyramids. In the second O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Fe3 trigonal bipyramids. In the third O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Fe3+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Fe3+ atoms. In the fifth O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Fe3 trigonal bipyramids. In the sixth O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Fe3 square pyramids. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Fe3+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Fe3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(FeO2)2 by Materials Project

MgFe2O4 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.19–2.53 Å. In the second Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.20–2.53 Å. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of Fe–O bond distances ranging from 1.90–2.00 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of Fe–O bond distances ranging from 1.90–2.00 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of Fe–O bond distances ranging from 1.90–2.01 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of Fe–O bond distances ranging from 1.91–2.01 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the second O2- site, O2- is bonded to two equivalent Mg2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the third O2- site, O2- is bonded to two equivalent Mg2+ and three equivalent Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fourth O2- site, O2- is bonded to two equivalent Mg2+ and three equivalent Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to two Mg2+ and three Fe3+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to two Mg2+ and three Fe3+ atoms. In the seventh O2- site, O2- is bonded to two equivalent Mg2+ and three equivalent Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the eighth O2- site, O2- is bonded to two equivalent Mg2+ and three equivalent Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y(FeO2)2 by Materials Project

YFe2O4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Y3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.39–2.44 Å. There are two inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.95 Å) and two longer (2.02 Å) Fe–O bond length. In the second Fe+2.50+ site, Fe+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.95 Å) and two longer (2.03 Å) Fe–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Y3+ and two Fe+2.50+ atoms to form a mixture of distorted edge and corner-sharing OY2Fe2 tetrahedra. In the second O2- site, O2- is bonded to two equivalent Y3+ and two Fe+2.50+ atoms to form a mixture of distorted edge and corner-sharing OY2Fe2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zn(FeO2)2 by Materials Project

ZnFe2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.08 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Fe–O bond distances ranging from 1.92–1.96 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent FeO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.09 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.09 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.07 Å. In the sixth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Fe–O bond distances ranging from 1.91–1.96 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.03–2.07 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.08 Å. In the ninth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Fe–O bond distances ranging from 1.92–1.97 Å. In the tenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.08 Å. In the eleventh Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six FeO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Fe–O bond distances ranging from 1.92–1.97 Å. In the twelfth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Fe–O bond distances ranging from 1.88–2.07 Å. There are six inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Zn–O bond distances ranging from 1.99–2.03 Å. In the second Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six FeO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.16 Å. In the third Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four FeO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.09–2.18 Å. In the fourth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six FeO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.16 Å. In the fifth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six FeO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.10–2.15 Å. In the sixth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five FeO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.09–2.16 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 Fe3+ and two Zn2+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe3+ and two Zn2+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to four Fe3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe3+ and one Zn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(FeO2)2 by Materials Project

CaFe2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six 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 FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–68°. There are a spread of Ca–O bond distances ranging from 2.18–2.26 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six FeO4 tetrahedra, edges with two CaO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.34 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four FeO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.22–2.33 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six FeO4 tetrahedra, edges with two CaO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.28–2.33 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six FeO4 tetrahedra, edges with two CaO6 octahedra, and edges with four FeO6 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 a cornercorner with one CaO4 tetrahedra, corners with five FeO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.31 Å. There are twelve inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four FeO4 tetrahedra, edges with three CaO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.95–2.17 Å. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six CaO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Fe–O bond distances ranging from 1.91–2.05 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent FeO4 tetrahedra, edges with two CaO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.96–2.20 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four FeO4 tetrahedra, edges with three CaO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.95–2.25 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.18 Å. In the sixth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six CaO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 48–60°. There are a spread of Fe–O bond distances ranging from 1.90–2.02 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.16 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five FeO4 tetrahedra, edges with three CaO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.22 Å. In the ninth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six CaO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–61°. There are a spread of Fe–O bond distances ranging from 1.90–2.04 Å. In the tenth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five FeO4 tetrahedra, edges with three CaO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.97–2.34 Å. In the eleventh Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six CaO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 50–61°. There are a spread of Fe–O bond distances ranging from 1.90–2.04 Å. In the twelfth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Fe–O bond distances ranging from 1.94–2.13 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Fe2 trigonal pyramids. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the third O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form a mixture of distorted edge and corner-sharing OCa2Fe2 trigonal pyramids. In the fourth O2- site, O2- is bonded to one Ca2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OCaFe3 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the seventeenth O2- site, O2- is bonded to two Ca2+ and two Fe3+ atoms to form corner-sharing OCa2Fe2 tetrahedra. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Fe3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V(FeO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al(FeO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li(FeO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(FeO2)2 by Materials Project

TmFe2O4 is Aluminum carbonitride-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent O2- atoms to form TmO6 octahedra that share corners with six equivalent FeO5 trigonal bipyramids and edges with six equivalent TmO6 octahedra. All Tm–O bond lengths are 2.26 Å. Fe+2.50+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with three equivalent TmO6 octahedra, corners with six equivalent FeO5 trigonal bipyramids, and edges with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. There are a spread of Fe–O bond distances ranging from 1.99–2.18 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Fe+2.50+ atoms to form OFe4 trigonal pyramids that share corners with four equivalent OTm3Fe tetrahedra, corners with six equivalent OFe4 trigonal pyramids, and edges with three equivalent OFe4 trigonal pyramids. In the second O2- site, O2- is bonded to three equivalent Tm3+ and one Fe+2.50+ atom to form OTm3Fe tetrahedra that share corners with nine equivalent OTm3Fe tetrahedra, corners with four equivalent OFe4 trigonal pyramids, and edges with three equivalent OTm3Fe tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li(FeO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiZn(FeO2)4 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(FeO2)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
NASA NTRS2018

Reliability of the Danish Aerospace Corporation Portable Pulmonary Function System

Metabolic gas analysis is a critical component of investigations that measure cardio-pulmonary exercise responses during and after long-duration spaceflight. The primary purpose of the current study was to determine the reliability and intra-subject repeatability of a metabolic gas analysis device, the Portable Pulmonary Function System (PPFS), designed for use on the International Space Station (ISS). The second objective of this study was to directly compare PPFS measurements of expired oxygen and carbon dioxide (FEO2 and FECO2) to values obtained from a well-validated clinical metabolic gas analysis system (ParvoMedics TrueOne (c) [PM]). Eight subjects performed four peak cycle tests to maximal exertion. The first test was used to prescribe work rates for the subsequent test sessions. Metabolic gas analysis for this test was performed by the PM, but samples of FEO2 and FECO2 also were simultaneously collected for analysis by the PPFS. Subjects then performed three additional peak cycle tests, consisting of three 5-min stages designed to elicit 25%, 50%, and 75% maximal oxygen consumption (VO2max) followed by stepwise increases of 25 W/min until subjects reached volitional exhaustion. Metabolic gas analysis was performed using the PPFS for these tests. Intraclass correlation coefficients (ICC), within-subject standard deviations (WS SD), and coefficients of variation (CV%) were calculated for the repeated exercise tests. Mixed model regression analysis was used to compare paired FEO2 and FECO2 values obtained from the PPFS and the PM during the initial test. The ICC values for oxygen consumption (VO2), carbon dioxide production (VCO2), and ventilation (VE) indicate that the PPFS is highly reliable (0.79 to 0.99) for all exercise levels tested; however, ICCs for respiratory exchange ratio (RER) were low ( 0.11 - 0.51), indicating poor agreement between trials during submaximal and maximal exercise. Overall, CVs ranged from 1.6% to 6.7% for all measurements, a finding consistent with reported values that were obtained using other metabolic gas analysis techniques. The PPFS and PM produced comparable FEO2 data; however, there was less agreement between measures of FECO2 obtained from the two devices, particularly at lower CO2 concentrations. The PPFS appears, in practically all respects, to yield highly reliable metabolic gas analysis data. Lower reliability of RER measurements reported in the literature and likely is not a function of the PPFS device. Further examination of PPFS CO2 data is warranted to better understand the limitations of these PPFS measurements. Overall, the PPFS when used for repeated measures of cardio-pulmonary exercise should provide accurate and reliable data for studies of human adaptation to spaceflight.

Portable Pulmonary Function System (PPFS)↗
NASA NTRSDate not supplied

Gaseous By-Product of Thermal Vacuum Processing of Lunar Highland Simulant

Scientists at Kennedy Space Center are advancing technologies to achieve oxygen extraction on the Lunar surface. One such technology is Molten Regolith Electrolysis (MRE) in which regolith simulant is melted under high temperatures to perform oxygen extraction through electrolysis of the melt pool. A study was conducted to understand the molten formation and proper-ties of Lunar Highlands Simulants (LHS-1) under high vacuum environments ranging between 10-6 Torr. These studies include investigating the regolith melt behavior and by-product gas analysis systems to prepare for pilot plant development and operations. The off-gassing rates and pressure build-up, gaseous compounds, and material compatibility may be a risk to MRE systems. The KSC findings are reported here for inclusion into future mis-sion architecture and operational planning. The four stages of the experiment were vacuum, resistive heating, regolith melt and gas detection. The regolith mass of 70 g was melted in a 40 cm tall x 50 cm diameter vacuum chamber at temperature increase rate 47 ℃ /min and ramp rate of 1 ampere/3 min up to an 18-amp maximum. The test is conducted for about 60 minutes and the constituent gases produced during heating of regolith is monitored with a re-sidual gas analyzer. During the molten formation, primary off-gassing volatiles included water vapor (18 amu), a peak at 44 amu (FeO2 – expected), and atomic oxygen (16 amu), among a series of other compounds that could create compatibility issues such as magnesium, chlorine, and silicon oxide. These results add to the knowledge required for successful oxygen extraction on the moon.

Molten Regolith Electrolysis↗