Sm2Mo2O7 crystallizes in the orthorhombic Pmn2_1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a distorted hexagonal planar geometry to one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. In the second Sm site, Sm(2) is bonded in a distorted hexagonal planar geometry to one O(10), one O(2), one O(3), one O(5), one O(6), and one O(9) atom. In the third Sm site, Sm(3) is bonded in a distorted hexagonal planar geometry to one O(7), one O(8), two equivalent O(2), and two equivalent O(9) atoms. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 7-coordinate geometry to one O(10), one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms. In the second Mo site, Mo(2) is bonded in a body-centered cubic geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. In the third Mo site, Mo(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(3), two equivalent O(2), and two equivalent O(9) atoms. There are ten inequivalent O sites. In the first O site, O(10) is bonded to two equivalent Sm(2), one Mo(1), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mo(3) and two equivalent Mo(2) atoms. In the third O site, O(2) is bonded to one Sm(2), one Sm(3), one Mo(2), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the fourth O site, O(3) is bonded to two equivalent Sm(2), one Mo(1), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the fifth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mo(1) and two equivalent Mo(2) atoms. In the sixth O site, O(5) is bonded to one Sm(1), one Sm(2), one Mo(1), and one Mo(2) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the seventh O site, O(6) is bonded to one Sm(1), one Sm(2), one Mo(1), and one Mo(2) atom to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the eighth O site, O(7) is bonded to one Sm(1), one Sm(3), and two equivalent Mo(2) atoms to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the ninth O site, O(8) is bonded to one Sm(1), one Sm(3), and two equivalent Mo(2) atoms to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the tenth O site, O(9) is bonded to one Sm(2), one Sm(3), one Mo(2), and one Mo(3) atom to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra.
Sm2Mo2O7 crystallizes in the orthorhombic Pmn2_1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a distorted hexagonal planar geometry to one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. The Sm(1)-O(7) bond length is 2.40 Å. The Sm(1)-O(8) bond length is 2.27 Å. Both Sm(1)-O(5) bond lengths are 2.47 Å. Both Sm(1)-O(6) bond lengths are 2.28 Å. In the second Sm site, Sm(2) is bonded in a distorted hexagonal planar geometry to one O(10), one O(2), one O(3), one O(5), one O(6), and one O(9) atom. The Sm(2)-O(10) bond length is 2.37 Å. The Sm(2)-O(2) bond length is 2.45 Å. The Sm(2)-O(3) bond length is 2.42 Å. The Sm(2)-O(5) bond length is 2.45 Å. The Sm(2)-O(6) bond length is 2.34 Å. The Sm(2)-O(9) bond length is 2.33 Å. In the third Sm site, Sm(3) is bonded in a distorted hexagonal planar geometry to one O(7), one O(8), two equivalent O(2), and two equivalent O(9) atoms. The Sm(3)-O(7) bond length is 2.29 Å. The Sm(3)-O(8) bond length is 2.38 Å. Both Sm(3)-O(2) bond lengths are 2.48 Å. Both Sm(3)-O(9) bond lengths are 2.30 Å. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 7-coordinate geometry to one O(10), one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms. The Mo(1)-O(10) bond length is 2.03 Å. The Mo(1)-O(3) bond length is 2.32 Å. The Mo(1)-O(4) bond length is 1.95 Å. Both Mo(1)-O(5) bond lengths are 2.09 Å. Both Mo(1)-O(6) bond lengths are 2.16 Å. In the second Mo site, Mo(2) is bonded in a body-centered cubic geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Mo(2)-O(1) bond length is 2.17 Å. The Mo(2)-O(2) bond length is 2.29 Å. The Mo(2)-O(4) bond length is 2.16 Å. The Mo(2)-O(5) bond length is 2.26 Å. The Mo(2)-O(6) bond length is 2.22 Å. The Mo(2)-O(7) bond length is 2.20 Å. The Mo(2)-O(8) bond length is 2.21 Å. The Mo(2)-O(9) bond length is 2.20 Å. In the third Mo site, Mo(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(3), two equivalent O(2), and two equivalent O(9) atoms. The Mo(3)-O(1) bond length is 1.96 Å. The Mo(3)-O(10) bond length is 2.35 Å. The Mo(3)-O(3) bond length is 2.01 Å. Both Mo(3)-O(2) bond lengths are 2.06 Å. Both Mo(3)-O(9) bond lengths are 2.16 Å. There are ten inequivalent O sites. In the first O site, O(10) is bonded to two equivalent Sm(2), one Mo(1), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the second O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Mo(3) and two equivalent Mo(2) atoms. In the third O site, O(2) is bonded to one Sm(2), one Sm(3), one Mo(2), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the fourth O site, O(3) is bonded to two equivalent Sm(2), one Mo(1), and one Mo(3) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the fifth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mo(1) and two equivalent Mo(2) atoms. In the sixth O site, O(5) is bonded to one Sm(1), one Sm(2), one Mo(1), and one Mo(2) atom to form a mixture of distorted corner and edge-sharing OSm2Mo2 tetrahedra. In the seventh O site, O(6) is bonded to one Sm(1), one Sm(2), one Mo(1), and one Mo(2) atom to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the eighth O site, O(7) is bonded to one Sm(1), one Sm(3), and two equivalent Mo(2) atoms to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the ninth O site, O(8) is bonded to one Sm(1), one Sm(3), and two equivalent Mo(2) atoms to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra. In the tenth O site, O(9) is bonded to one Sm(2), one Sm(3), one Mo(2), and one Mo(3) atom to form a mixture of corner and edge-sharing OSm2Mo2 tetrahedra.