Materials Data on SiO2 by Materials Project

Abstract

SiO2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of four trioxidane molecules and two Si14O25 sheets oriented in the (1, 0, 0) direction. In each Si14O25 sheet, there are seven 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 1.62–1.64 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded in a water-like geometry to two O2- atoms. There is one shorter (1.64 Å) and one longer (1.65 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Si–O bond distances ranging from 1.66–2.09 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is three shorter (1.63 Å) and one longer (1.64 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.62 Å) and two longer (1.65 Å) Si–O bond length. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form a mixture of corner and edge-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in an L-shaped geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in an L-shaped geometry to two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Si4+ and one O2- atom. The O–O bond length is 1.52 Å. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Si4+ atoms.