Sc2O3 crystallizes in the orthorhombic Pna2_1 space group. There are four inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(6) atoms to form ScO6 octahedra that share corners with two equivalent Sc(4)O6 octahedra, corners with three equivalent Sc(2)O4 tetrahedra, edges with two equivalent Sc(1)O6 octahedra, edges with two equivalent Sc(4)O6 octahedra, and edges with three equivalent Sc(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-49°. In the second Sc site, Sc(2) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form ScO4 tetrahedra that share  a cornercorner with one Sc(4)O6 octahedra, corners with three equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra, and corners with two equivalent Sc(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-69°. In the third Sc site, Sc(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted ScO6 octahedra that share corners with four equivalent Sc(4)O6 octahedra, corners with four equivalent Sc(2)O4 tetrahedra,  an edgeedge with one Sc(4)O6 octahedra, and edges with three equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-57°. In the fourth Sc site, Sc(4) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form distorted ScO6 octahedra that share corners with two equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra,  a cornercorner with one Sc(2)O4 tetrahedra,  an edgeedge with one Sc(3)O6 octahedra, edges with two equivalent Sc(1)O6 octahedra, and edges with two equivalent Sc(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-57°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Sc(1), one Sc(2), one Sc(3), and one Sc(4) atom to form OSc4 tetrahedra that share  a cornercorner with one O(2)Sc5 square pyramid, corners with two equivalent O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, and  an edgeedge with one O(6)Sc4 tetrahedra. In the second O site, O(2) is bonded to one Sc(3), two equivalent Sc(1), and two equivalent Sc(4) atoms to form OSc5 square pyramids that share  a cornercorner with one O(1)Sc4 tetrahedra,  a cornercorner with one O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, edges with two equivalent O(1)Sc4 tetrahedra, and edges with two equivalent O(6)Sc4 tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to one Sc(3) and two equivalent Sc(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Sc(3) and two equivalent Sc(4) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Sc(1), one Sc(3), and one Sc(4) atom. In the sixth O site, O(6) is bonded to one Sc(2), one Sc(3), and two equivalent Sc(1) atoms to form OSc4 tetrahedra that share  a cornercorner with one O(2)Sc5 square pyramid, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, and  an edgeedge with one O(1)Sc4 tetrahedra.
Sc2O3 crystallizes in the orthorhombic Pna2_1 space group. There are four inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(6) atoms to form ScO6 octahedra that share corners with two equivalent Sc(4)O6 octahedra, corners with three equivalent Sc(2)O4 tetrahedra, edges with two equivalent Sc(1)O6 octahedra, edges with two equivalent Sc(4)O6 octahedra, and edges with three equivalent Sc(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-49°. The Sc(1)-O(1) bond length is 2.16 Å. The Sc(1)-O(5) bond length is 2.04 Å. There is one shorter (2.15 Å) and one longer (2.16 Å) Sc(1)-O(2) bond length. There is one shorter (2.15 Å) and one longer (2.17 Å) Sc(1)-O(6) bond length. In the second Sc site, Sc(2) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form ScO4 tetrahedra that share  a cornercorner with one Sc(4)O6 octahedra, corners with three equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra, and corners with two equivalent Sc(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-69°. The Sc(2)-O(1) bond length is 2.01 Å. The Sc(2)-O(6) bond length is 2.02 Å. There is one shorter (1.97 Å) and one longer (1.98 Å) Sc(2)-O(3) bond length. In the third Sc site, Sc(3) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted ScO6 octahedra that share corners with four equivalent Sc(4)O6 octahedra, corners with four equivalent Sc(2)O4 tetrahedra,  an edgeedge with one Sc(4)O6 octahedra, and edges with three equivalent Sc(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-57°. The Sc(3)-O(1) bond length is 2.15 Å. The Sc(3)-O(2) bond length is 2.47 Å. The Sc(3)-O(3) bond length is 2.09 Å. The Sc(3)-O(4) bond length is 2.02 Å. The Sc(3)-O(5) bond length is 2.05 Å. The Sc(3)-O(6) bond length is 2.24 Å. In the fourth Sc site, Sc(4) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form distorted ScO6 octahedra that share corners with two equivalent Sc(1)O6 octahedra, corners with four equivalent Sc(3)O6 octahedra,  a cornercorner with one Sc(2)O4 tetrahedra,  an edgeedge with one Sc(3)O6 octahedra, edges with two equivalent Sc(1)O6 octahedra, and edges with two equivalent Sc(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-57°. The Sc(4)-O(1) bond length is 2.16 Å. The Sc(4)-O(5) bond length is 2.03 Å. There is one shorter (2.29 Å) and one longer (2.45 Å) Sc(4)-O(2) bond length. There is one shorter (2.06 Å) and one longer (2.07 Å) Sc(4)-O(4) bond length. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Sc(1), one Sc(2), one Sc(3), and one Sc(4) atom to form OSc4 tetrahedra that share  a cornercorner with one O(2)Sc5 square pyramid, corners with two equivalent O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, and  an edgeedge with one O(6)Sc4 tetrahedra. In the second O site, O(2) is bonded to one Sc(3), two equivalent Sc(1), and two equivalent Sc(4) atoms to form OSc5 square pyramids that share  a cornercorner with one O(1)Sc4 tetrahedra,  a cornercorner with one O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, edges with two equivalent O(1)Sc4 tetrahedra, and edges with two equivalent O(6)Sc4 tetrahedra. In the third O site, O(3) is bonded in a trigonal planar geometry to one Sc(3) and two equivalent Sc(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Sc(3) and two equivalent Sc(4) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Sc(1), one Sc(3), and one Sc(4) atom. In the sixth O site, O(6) is bonded to one Sc(2), one Sc(3), and two equivalent Sc(1) atoms to form OSc4 tetrahedra that share  a cornercorner with one O(2)Sc5 square pyramid, corners with two equivalent O(1)Sc4 tetrahedra, corners with two equivalent O(6)Sc4 tetrahedra, edges with two equivalent O(2)Sc5 square pyramids, and  an edgeedge with one O(1)Sc4 tetrahedra.