DOE OSTI2020
Sr4Mn5O15 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with five SrO12 cuboctahedra, and faces with eight MnO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.59–2.83 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with ten SrO12 cuboctahedra, faces with four SrO12 cuboctahedra, and faces with eight MnO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.59–2.89 Å. In the third Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with ten SrO12 cuboctahedra, faces with four SrO12 cuboctahedra, and faces with eight MnO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.61–2.85 Å. In the fourth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with five SrO12 cuboctahedra, and faces with eight MnO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.55–2.90 Å. There are six inequivalent Mn+4.40+ sites. In the first Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–15°. There are a spread of Mn–O bond distances ranging from 1.91–1.97 Å. In the second Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–13°. There is two shorter (1.93 Å) and four longer (1.94 Å) Mn–O bond length. In the third Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–14°. There are a spread of Mn–O bond distances ranging from 1.91–1.98 Å. In the fourth Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–14°. There is four shorter (1.93 Å) and two longer (1.94 Å) Mn–O bond length. In the fifth Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–15°. There are a spread of Mn–O bond distances ranging from 1.86–2.00 Å. In the sixth Mn+4.40+ site, Mn+4.40+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO6 octahedra and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–13°. There are a spread of Mn–O bond distances ranging from 1.91–1.97 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Sr2+ and two Mn+4.40+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Mn+4.40+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+ and two Mn+4.40+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+ and two Mn+4.40+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Mn+4.40+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Sr2+ and two Mn+4.40+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Mn+4.40+ atoms. In the eighth O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Mn+4.40+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Mn+4.40+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+ and two Mn+4.40+ atoms. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Mn+4.40+ atoms. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Mn+4.40+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Mn+4.40+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Mn+4.40+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted linear geometry to three Sr2+ and two Mn+4.40+ atoms.