SiO2 crystallizes in the orthorhombic Imm2 space group. There are four inequivalent Si sites. In the first Si site, Si(1,4) is bonded to one O(11), one O(7), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(10), one O(12), one O(2), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(5,6) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5,6) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Si(1,4) and one Si(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5,6) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(6) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. In the seventh O site, O(7) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(1,4) and one Si(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to two equivalent Si(3) atoms. In the eleventh O site, O(11) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to two equivalent Si(3) atoms.
SiO2 crystallizes in the orthorhombic Imm2 space group. There are four inequivalent Si sites. In the first Si site, Si(1,4) is bonded to one O(11), one O(7), and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. The Si(1,4)-O(11) bond length is 1.67 Å. The Si(1,4)-O(7) bond length is 1.67 Å. Both Si(1,4)-O(8) bond lengths are 1.65 Å. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form corner-sharing SiO4 tetrahedra. The Si(2)-O(1) bond length is 1.64 Å. The Si(2)-O(3) bond length is 1.64 Å. The Si(2)-O(5) bond length is 1.65 Å. The Si(2)-O(9) bond length is 1.65 Å. In the third Si site, Si(3) is bonded to one O(10), one O(12), one O(2), and one O(8) atom to form corner-sharing SiO4 tetrahedra. The Si(3)-O(10) bond length is 1.65 Å. The Si(3)-O(12) bond length is 1.65 Å. The Si(3)-O(2) bond length is 1.64 Å. The Si(3)-O(8) bond length is 1.64 Å. In the fourth Si site, Si(5,6) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. The Si(5,6)-O(4) bond length is 1.67 Å. The Si(5,6)-O(6) bond length is 1.68 Å. Both Si(5,6)-O(1) bond lengths are 1.65 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5,6) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Si(1,4) and one Si(3) atom. The O(2)-Si(1,4) bond length is 1.65 Å. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5,6) atom. The O(3)-Si(5,6) bond length is 1.65 Å. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. The O(4)-Si(1,4) bond length is 1.67 Å. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(6) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. The O(6)-Si(1,4) bond length is 1.67 Å. In the seventh O site, O(7) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. The O(7)-Si(5,6) bond length is 1.67 Å. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(1,4) and one Si(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to two equivalent Si(3) atoms. In the eleventh O site, O(11) is bonded in an L-shaped geometry to one Si(1,4) and one Si(5,6) atom. The O(11)-Si(5,6) bond length is 1.68 Å. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to two equivalent Si(3) atoms.