DOE OSTI2020
BaSi2O5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.24 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 2.79–3.04 Å. There are three inequivalent Si4+ sites. In the first 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 second 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 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 1.59–1.66 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Si4+ atoms.