DOE OSTI2020
Mg9Fe3Al8(SiO4)12 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.22–2.38 Å. In the second Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.21–2.38 Å. In the third Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.22 Å) and four longer (2.37 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.22–2.38 Å. In the fifth Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.22–2.38 Å. In the sixth Mg2+ site, Mg2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.21–2.38 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Fe–O bond distances ranging from 2.25–2.39 Å. In the second Fe2+ site, Fe2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Fe–O bond distances ranging from 2.25–2.39 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra. There is two shorter (1.90 Å) and four longer (1.91 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra. There is two shorter (1.90 Å) and four longer (1.91 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra. There is three shorter (1.90 Å) and three longer (1.91 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra. There is two shorter (1.90 Å) and four longer (1.91 Å) Al–O bond length. There are eight inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. All Si–O bond lengths are 1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Si–O bond lengths are 1.65 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Si–O bond lengths are 1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. All Si–O bond lengths are 1.65 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Si–O bond lengths are 1.65 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. All Si–O bond lengths are 1.65 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–49°. All Si–O bond lengths are 1.65 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. All Si–O bond lengths are 1.65 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Fe2+, one Al3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, one Fe2+, one Al3+, and one Si4+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Fe2+, one Al3+, and one Si4+ atom. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+, one Al3+, and one Si4+ atom.