SiO2 crystallizes in the orthorhombic I2_12_12_1 space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(2) 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(3) atoms to form corner-sharing SiO4 tetrahedra. There are three 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 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms.
SiO2 crystallizes in the orthorhombic I2_12_12_1 space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. Both Si(1)-O(1) bond lengths are 1.64 Å. Both Si(1)-O(2) bond lengths are 1.67 Å. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. Both Si(2)-O(1) bond lengths are 1.65 Å. Both Si(2)-O(3) bond lengths are 1.63 Å. There are three 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 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms.