SmZr4O9 crystallizes in the orthorhombic Imm2 space group. Sm(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one O(2), one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of distorted edge and corner-sharing ZrO7 hexagonal pyramids. In the second Zr site, Zr(2) is bonded in a body-centered cubic geometry to one O(1), one O(4), three equivalent O(3), and three equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sm(1), one Zr(2), and two equivalent Zr(1) atoms to form OSmZr3 tetrahedra that share  a cornercorner with one O(5)Zr4 tetrahedra, corners with three equivalent O(1)SmZr3 tetrahedra, corners with three equivalent O(4)SmZr3 tetrahedra, corners with five equivalent O(3)Zr4 tetrahedra, edges with two equivalent O(4)SmZr3 tetrahedra, and edges with two equivalent O(5)Zr4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Zr(1) atoms. In the third O site, O(3) is bonded to one Zr(1) and three equivalent Zr(2) atoms to form OZr4 tetrahedra that share  a cornercorner with one O(4)SmZr3 tetrahedra, corners with two equivalent O(5)Zr4 tetrahedra, corners with five equivalent O(1)SmZr3 tetrahedra, corners with six equivalent O(3)Zr4 tetrahedra, edges with two equivalent O(4)SmZr3 tetrahedra, and edges with four equivalent O(5)Zr4 tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), one Zr(2), and two equivalent Zr(1) atoms to form OSmZr3 tetrahedra that share  a cornercorner with one O(3)Zr4 tetrahedra, corners with three equivalent O(1)SmZr3 tetrahedra, corners with three equivalent O(4)SmZr3 tetrahedra, corners with five equivalent O(5)Zr4 tetrahedra, edges with two equivalent O(1)SmZr3 tetrahedra, and edges with two equivalent O(3)Zr4 tetrahedra. In the fifth O site, O(5) is bonded to one Zr(1) and three equivalent Zr(2) atoms to form OZr4 tetrahedra that share  a cornercorner with one O(1)SmZr3 tetrahedra, corners with two equivalent O(3)Zr4 tetrahedra, corners with five equivalent O(4)SmZr3 tetrahedra, corners with six equivalent O(5)Zr4 tetrahedra, edges with two equivalent O(1)SmZr3 tetrahedra, and edges with four equivalent O(3)Zr4 tetrahedra.
SmZr4O9 crystallizes in the orthorhombic Imm2 space group. Sm(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Both Sm(1)-O(1) bond lengths are 2.33 Å. Both Sm(1)-O(2) bond lengths are 2.68 Å. Both Sm(1)-O(4) bond lengths are 2.35 Å. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to one O(2), one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of distorted edge and corner-sharing ZrO7 hexagonal pyramids. The Zr(1)-O(2) bond length is 2.11 Å. The Zr(1)-O(3) bond length is 2.18 Å. The Zr(1)-O(5) bond length is 2.18 Å. Both Zr(1)-O(1) bond lengths are 2.20 Å. Both Zr(1)-O(4) bond lengths are 2.23 Å. In the second Zr site, Zr(2) is bonded in a body-centered cubic geometry to one O(1), one O(4), three equivalent O(3), and three equivalent O(5) atoms. The Zr(2)-O(1) bond length is 2.15 Å. The Zr(2)-O(4) bond length is 2.30 Å. There are two shorter (2.21 Å) and one longer (2.33 Å) Zr(2)-O(3) bond length. There are two shorter (2.22 Å) and one longer (2.28 Å) Zr(2)-O(5) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sm(1), one Zr(2), and two equivalent Zr(1) atoms to form OSmZr3 tetrahedra that share  a cornercorner with one O(5)Zr4 tetrahedra, corners with three equivalent O(1)SmZr3 tetrahedra, corners with three equivalent O(4)SmZr3 tetrahedra, corners with five equivalent O(3)Zr4 tetrahedra, edges with two equivalent O(4)SmZr3 tetrahedra, and edges with two equivalent O(5)Zr4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Zr(1) atoms. In the third O site, O(3) is bonded to one Zr(1) and three equivalent Zr(2) atoms to form OZr4 tetrahedra that share  a cornercorner with one O(4)SmZr3 tetrahedra, corners with two equivalent O(5)Zr4 tetrahedra, corners with five equivalent O(1)SmZr3 tetrahedra, corners with six equivalent O(3)Zr4 tetrahedra, edges with two equivalent O(4)SmZr3 tetrahedra, and edges with four equivalent O(5)Zr4 tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), one Zr(2), and two equivalent Zr(1) atoms to form OSmZr3 tetrahedra that share  a cornercorner with one O(3)Zr4 tetrahedra, corners with three equivalent O(1)SmZr3 tetrahedra, corners with three equivalent O(4)SmZr3 tetrahedra, corners with five equivalent O(5)Zr4 tetrahedra, edges with two equivalent O(1)SmZr3 tetrahedra, and edges with two equivalent O(3)Zr4 tetrahedra. In the fifth O site, O(5) is bonded to one Zr(1) and three equivalent Zr(2) atoms to form OZr4 tetrahedra that share  a cornercorner with one O(1)SmZr3 tetrahedra, corners with two equivalent O(3)Zr4 tetrahedra, corners with five equivalent O(4)SmZr3 tetrahedra, corners with six equivalent O(5)Zr4 tetrahedra, edges with two equivalent O(1)SmZr3 tetrahedra, and edges with four equivalent O(3)Zr4 tetrahedra.