Sc20O19 crystallizes in the tetragonal I4/m space group. There are five inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(3), one O(4), and three equivalent O(2) atoms to form ScO6 octahedra that share corners with five equivalent Sc(1)O6 octahedra,  a cornercorner with one Sc(4)O5 square pyramid, edges with two equivalent Sc(5)O6 octahedra, edges with three equivalent Sc(1)O6 octahedra, edges with three equivalent Sc(3)O6 octahedra,  an edgeedge with one Sc(4)O5 square pyramid, and edges with three equivalent Sc(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-4°. In the second Sc site, Sc(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form ScO5 square pyramids that share  a cornercorner with one Sc(5)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra, corners with two equivalent Sc(2)O5 square pyramids, corners with two equivalent Sc(4)O5 square pyramids,  an edgeedge with one Sc(3)O6 octahedra,  an edgeedge with one Sc(5)O6 octahedra, and edges with six equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third Sc site, Sc(3) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form ScO6 octahedra that share  a cornercorner with one Sc(3)O6 octahedra,  a cornercorner with one Sc(5)O6 octahedra, corners with four equivalent Sc(2)O5 square pyramids,  an edgeedge with one Sc(5)O6 octahedra, edges with two equivalent Sc(3)O6 octahedra, edges with six equivalent Sc(1)O6 octahedra,  an edgeedge with one Sc(2)O5 square pyramid, and edges with two equivalent Sc(4)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth Sc site, Sc(4) is bonded to one O(5) and four equivalent O(2) atoms to form ScO5 square pyramids that share corners with four equivalent Sc(1)O6 octahedra,  a cornercorner with one Sc(4)O5 square pyramid, corners with four equivalent Sc(2)O5 square pyramids, edges with four equivalent Sc(1)O6 octahedra, and edges with four equivalent Sc(3)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth Sc site, Sc(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with two equivalent Sc(3)O6 octahedra, corners with two equivalent Sc(5)O6 octahedra, corners with two equivalent Sc(2)O5 square pyramids, edges with two equivalent Sc(3)O6 octahedra, edges with eight equivalent Sc(1)O6 octahedra, and edges with two equivalent Sc(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sc(2), one Sc(5), two equivalent Sc(1), and two equivalent Sc(3) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Sc(2), one Sc(3), one Sc(4), and three equivalent Sc(1) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. In the third O site, O(3) is bonded to one Sc(3), one Sc(5), two equivalent Sc(1), and two equivalent Sc(2) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the fourth O site, O(4) is bonded to two equivalent Sc(5) and four equivalent Sc(1) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded to two equivalent Sc(4) and four equivalent Sc(3) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles are 2°.
Sc20O19 crystallizes in the tetragonal I4/m space group. There are five inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(3), one O(4), and three equivalent O(2) atoms to form ScO6 octahedra that share corners with five equivalent Sc(1)O6 octahedra,  a cornercorner with one Sc(4)O5 square pyramid, edges with two equivalent Sc(5)O6 octahedra, edges with three equivalent Sc(1)O6 octahedra, edges with three equivalent Sc(3)O6 octahedra,  an edgeedge with one Sc(4)O5 square pyramid, and edges with three equivalent Sc(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-4°. The Sc(1)-O(1) bond length is 2.25 Å. The Sc(1)-O(3) bond length is 2.23 Å. The Sc(1)-O(4) bond length is 2.27 Å. There are a spread of Sc(1)-O(2) bond distances ranging from 2.21-2.24 Å. In the second Sc site, Sc(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form ScO5 square pyramids that share  a cornercorner with one Sc(5)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra, corners with two equivalent Sc(2)O5 square pyramids, corners with two equivalent Sc(4)O5 square pyramids,  an edgeedge with one Sc(3)O6 octahedra,  an edgeedge with one Sc(5)O6 octahedra, and edges with six equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Sc(2)-O(1) bond length is 2.25 Å. Both Sc(2)-O(2) bond lengths are 2.25 Å. There is one shorter (2.25 Å) and one longer (2.27 Å) Sc(2)-O(3) bond length. In the third Sc site, Sc(3) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form ScO6 octahedra that share  a cornercorner with one Sc(3)O6 octahedra,  a cornercorner with one Sc(5)O6 octahedra, corners with four equivalent Sc(2)O5 square pyramids,  an edgeedge with one Sc(5)O6 octahedra, edges with two equivalent Sc(3)O6 octahedra, edges with six equivalent Sc(1)O6 octahedra,  an edgeedge with one Sc(2)O5 square pyramid, and edges with two equivalent Sc(4)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. The Sc(3)-O(3) bond length is 2.24 Å. The Sc(3)-O(5) bond length is 2.24 Å. There is one shorter (2.22 Å) and one longer (2.24 Å) Sc(3)-O(1) bond length. Both Sc(3)-O(2) bond lengths are 2.23 Å. In the fourth Sc site, Sc(4) is bonded to one O(5) and four equivalent O(2) atoms to form ScO5 square pyramids that share corners with four equivalent Sc(1)O6 octahedra,  a cornercorner with one Sc(4)O5 square pyramid, corners with four equivalent Sc(2)O5 square pyramids, edges with four equivalent Sc(1)O6 octahedra, and edges with four equivalent Sc(3)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. The Sc(4)-O(5) bond length is 2.24 Å. All Sc(4)-O(2) bond lengths are 2.26 Å. In the fifth Sc site, Sc(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form ScO6 octahedra that share corners with two equivalent Sc(3)O6 octahedra, corners with two equivalent Sc(5)O6 octahedra, corners with two equivalent Sc(2)O5 square pyramids, edges with two equivalent Sc(3)O6 octahedra, edges with eight equivalent Sc(1)O6 octahedra, and edges with two equivalent Sc(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. Both Sc(5)-O(1) bond lengths are 2.25 Å. Both Sc(5)-O(3) bond lengths are 2.21 Å. Both Sc(5)-O(4) bond lengths are 2.24 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sc(2), one Sc(5), two equivalent Sc(1), and two equivalent Sc(3) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Sc(2), one Sc(3), one Sc(4), and three equivalent Sc(1) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. In the third O site, O(3) is bonded to one Sc(3), one Sc(5), two equivalent Sc(1), and two equivalent Sc(2) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the fourth O site, O(4) is bonded to two equivalent Sc(5) and four equivalent Sc(1) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded to two equivalent Sc(4) and four equivalent Sc(3) atoms to form a mixture of corner and edge-sharing OSc6 octahedra. The corner-sharing octahedral tilt angles are 2°.