SiO2 crystallizes in the orthorhombic Ccce space group. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(5) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing SiO4 tetrahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(3) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom.
SiO2 crystallizes in the orthorhombic Ccce space group. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(5) atoms to form corner-sharing SiO4 tetrahedra. Both Si(1)-O(1) bond lengths are 1.66 Å. Both Si(1)-O(5) bond lengths are 1.63 Å. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. Both Si(2)-O(1) bond lengths are 1.65 Å. Both Si(2)-O(4) bond lengths are 1.64 Å. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing SiO4 tetrahedra. The Si(3)-O(2) bond length is 1.62 Å. The Si(3)-O(3) bond length is 1.61 Å. The Si(3)-O(4) bond length is 1.66 Å. The Si(3)-O(5) bond length is 1.66 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(3) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom.