DOE OSTI2020
BaMn2Fe4O11 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, edges with two FeO6 octahedra, edges with four MnO6 octahedra, edges with three equivalent FeO5 trigonal bipyramids, and faces with six FeO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.82–2.96 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, edges with two FeO6 octahedra, edges with four MnO6 octahedra, edges with three equivalent FeO5 trigonal bipyramids, and faces with six FeO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.82–2.96 Å. There are four inequivalent Mn+4.50+ sites. In the first Mn+4.50+ site, Mn+4.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, edges with two equivalent MnO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Mn–O bond distances ranging from 1.93–2.00 Å. In the second Mn+4.50+ site, Mn+4.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, edges with two equivalent MnO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Mn–O bond distances ranging from 1.93–1.99 Å. In the third Mn+4.50+ site, Mn+4.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, edges with two equivalent MnO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Mn–O bond distances ranging from 1.93–2.00 Å. In the fourth Mn+4.50+ site, Mn+4.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, edges with two equivalent MnO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Mn–O bond distances ranging from 1.93–1.99 Å. There are eight inequivalent Fe+2.75+ sites. In the first Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four MnO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent BaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the second Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four MnO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent BaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Fe–O bond distances ranging from 1.99–2.10 Å. In the third Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four MnO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent BaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Fe–O bond distances ranging from 1.98–2.13 Å. In the fourth Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four MnO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent BaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Fe–O bond distances ranging from 1.99–2.11 Å. In the fifth Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Fe–O bond distances ranging from 2.01–2.08 Å. In the sixth Fe+2.75+ site, Fe+2.75+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four FeO6 octahedra, corners with two FeO5 trigonal bipyramids, edges with two BaO12 cuboctahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Fe–O bond distances ranging from 2.01–2.09 Å. In the seventh Fe+2.75+ site, Fe+2.75+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with four MnO6 octahedra, corners with eight FeO6 octahedra, and edges with three equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 34–62°. There are a spread of Fe–O bond distances ranging from 1.88–2.62 Å. In the eighth Fe+2.75+ site, Fe+2.75+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with four MnO6 octahedra, corners with eight FeO6 octahedra, and edges with three equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 34–62°. There are a spread of Fe–O bond distances ranging from 1.88–2.63 Å. There are twenty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, two Mn+4.50+, and one Fe+2.75+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, two Mn+4.50+, and one Fe+2.75+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, two Mn+4.50+, and one Fe+2.75+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, two Mn+4.50+, and one Fe+2.75+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Mn+4.50+, and two Fe+2.75+ atoms. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mn+4.50+ and two Fe+2.75+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mn+4.50+ and two Fe+2.75+ atoms. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mn+4.50+ and two Fe+2.75+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mn+4.50+ and two Fe+2.75+ atoms. In the seventeenth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms. In the eighteenth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms. In the nineteenth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms. In the twentieth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms. In the twenty-first O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms. In the twenty-second O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe+2.75+ atoms.