Cs5YO4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Cs site, Cs(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted CsO4 tetrahedra that share corners with four equivalent Y(1)O4 tetrahedra. Y(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form YO4 tetrahedra that share corners with four equivalent Cs(2)O4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Cs(2), four equivalent Cs(1), and one Y(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Cs(2), four equivalent Cs(1), and one Y(1) atom.
Cs5YO4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.93 Å) and one longer (2.94 Å) Cs(1)-O(1) bond length. There is one shorter (3.11 Å) and one longer (3.22 Å) Cs(1)-O(2) bond length. In the second Cs site, Cs(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form distorted CsO4 tetrahedra that share corners with four equivalent Y(1)O4 tetrahedra. Both Cs(2)-O(1) bond lengths are 3.42 Å. Both Cs(2)-O(2) bond lengths are 2.85 Å. Y(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form YO4 tetrahedra that share corners with four equivalent Cs(2)O4 tetrahedra. Both Y(1)-O(1) bond lengths are 2.18 Å. Both Y(1)-O(2) bond lengths are 2.17 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Cs(2), four equivalent Cs(1), and one Y(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Cs(2), four equivalent Cs(1), and one Y(1) atom.