Zr2Si2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. In the second Zr site, Zr(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form distorted ZrO12 cuboctahedra that share corners with four equivalent Zr(2)O12 cuboctahedra, faces with four equivalent Zr(2)O12 cuboctahedra, and faces with eight equivalent Si(1)O5 square pyramids. Si(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted SiO5 square pyramids that share corners with five equivalent Si(1)O5 square pyramids and faces with four equivalent Zr(2)O12 cuboctahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Zr(1), two equivalent Zr(2), and two equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing OZr4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Zr(2) and two equivalent Si(1) atoms.
Zr2Si2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Zr(1)-O(1) bond lengths are 2.43 Å. In the second Zr site, Zr(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form distorted ZrO12 cuboctahedra that share corners with four equivalent Zr(2)O12 cuboctahedra, faces with four equivalent Zr(2)O12 cuboctahedra, and faces with eight equivalent Si(1)O5 square pyramids. All Zr(2)-O(2) bond lengths are 2.75 Å. All Zr(2)-O(1) bond lengths are 2.48 Å. Si(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted SiO5 square pyramids that share corners with five equivalent Si(1)O5 square pyramids and faces with four equivalent Zr(2)O12 cuboctahedra. The Si(1)-O(2) bond length is 1.77 Å. All Si(1)-O(1) bond lengths are 1.96 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Zr(1), two equivalent Zr(2), and two equivalent Si(1) atoms to form a mixture of distorted face, corner, and edge-sharing OZr4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-69°. In the second O site, O(2) is bonded in a linear geometry to four equivalent Zr(2) and two equivalent Si(1) atoms.