DOE OSTI2020
Ba5Si8O21 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are ten inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.67–3.12 Å. In the second Ba2+ site, Ba2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.09 Å. In the third Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.65–3.13 Å. In the fourth Ba2+ site, Ba2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.06 Å. In the fifth Ba2+ site, Ba2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.09 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to six O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–2.89 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.66–3.14 Å. In the eighth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to six O2- atoms. There are a spread of Ba–O bond distances ranging from 2.85–2.87 Å. In the ninth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.66–3.16 Å. In the tenth Ba2+ site, Ba2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.09 Å. There are sixteen inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.68 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.68 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the ninth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the tenth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.68 Å) Si–O bond length. In the eleventh Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the twelfth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the thirteenth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fourteenth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fifteenth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.60 Å) and three longer (1.66 Å) Si–O bond length. In the sixteenth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.62 Å) and two longer (1.68 Å) Si–O bond length. There are forty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Si4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the twenty-seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Si4+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the twenty-ninth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirtieth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Si4+ atoms. In the thirty-second O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-third O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-fifth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the thirty-seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-eighth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the thirty-ninth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the fortieth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Si4+ atoms. In the forty-first O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two Si4+ atoms. In the forty-second O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom.