Mo2Ni3SeO11 crystallizes in the triclinic P-1 space group. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(5), one O(7), and two equivalent O(8) atoms. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(10), one O(4), one O(5), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. In the second Ni site, Ni(2) is bonded to one O(10), one O(6), one O(7), one O(9), and two equivalent O(2) atoms to form edge-sharing NiO6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(11), one O(2), one O(3), one O(4), and one O(6) atom to form edge-sharing NiO6 octahedra. Se(1) is bonded in a trigonal non-coplanar geometry to one O(10), one O(11), and one O(6) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mo(1) and one Ni(1) atom. In the second O site, O(2) is bonded to one Mo(2), one Ni(3), and two equivalent Ni(2) atoms to form distorted ONi3Mo tetrahedra that share  a cornercorner with one O(10)Ni3Se trigonal pyramid,  an edgeedge with one O(2)Ni3Mo tetrahedra, and  an edgeedge with one O(10)Ni3Se trigonal pyramid. In the third O site, O(3) is bonded in a linear geometry to one Mo(2) and one Ni(3) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mo(1), one Mo(2), one Ni(1), and one Ni(3) atom. In the fifth O site, O(5) is bonded in a linear geometry to one Mo(1) and one Ni(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ni(2), one Ni(3), and one Se(1) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Mo(1), one Mo(2), one Ni(1), and one Ni(2) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Mo(2), two equivalent Mo(1), and one Ni(1) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Mo(2) and one Ni(2) atom. In the tenth O site, O(10) is bonded to one Ni(1), one Ni(2), one Ni(3), and one Se(1) atom to form a mixture of corner and edge-sharing ONi3Se trigonal pyramids. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Ni(3) and one Se(1) atom.
Mo2Ni3SeO11 crystallizes in the triclinic P-1 space group. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(5), one O(7), and two equivalent O(8) atoms. The Mo(1)-O(1) bond length is 1.76 Å. The Mo(1)-O(4) bond length is 1.95 Å. The Mo(1)-O(5) bond length is 1.76 Å. The Mo(1)-O(7) bond length is 1.95 Å. There is one shorter (2.30 Å) and one longer (2.32 Å) Mo(1)-O(8) bond length. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. The Mo(2)-O(2) bond length is 1.92 Å. The Mo(2)-O(3) bond length is 1.75 Å. The Mo(2)-O(4) bond length is 2.31 Å. The Mo(2)-O(7) bond length is 2.33 Å. The Mo(2)-O(8) bond length is 1.99 Å. The Mo(2)-O(9) bond length is 1.75 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(10), one O(4), one O(5), one O(7), and one O(8) atom to form edge-sharing NiO6 octahedra. The Ni(1)-O(1) bond length is 2.03 Å. The Ni(1)-O(10) bond length is 2.07 Å. The Ni(1)-O(4) bond length is 2.11 Å. The Ni(1)-O(5) bond length is 2.02 Å. The Ni(1)-O(7) bond length is 2.12 Å. The Ni(1)-O(8) bond length is 2.05 Å. In the second Ni site, Ni(2) is bonded to one O(10), one O(6), one O(7), one O(9), and two equivalent O(2) atoms to form edge-sharing NiO6 octahedra. The Ni(2)-O(10) bond length is 2.14 Å. The Ni(2)-O(6) bond length is 2.12 Å. The Ni(2)-O(7) bond length is 2.14 Å. The Ni(2)-O(9) bond length is 2.00 Å. There is one shorter (2.10 Å) and one longer (2.11 Å) Ni(2)-O(2) bond length. In the third Ni site, Ni(3) is bonded to one O(10), one O(11), one O(2), one O(3), one O(4), and one O(6) atom to form edge-sharing NiO6 octahedra. The Ni(3)-O(10) bond length is 2.17 Å. The Ni(3)-O(11) bond length is 2.06 Å. The Ni(3)-O(2) bond length is 2.13 Å. The Ni(3)-O(3) bond length is 2.00 Å. The Ni(3)-O(4) bond length is 2.12 Å. The Ni(3)-O(6) bond length is 2.03 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one O(10), one O(11), and one O(6) atom. The Se(1)-O(10) bond length is 1.83 Å. The Se(1)-O(11) bond length is 1.68 Å. The Se(1)-O(6) bond length is 1.74 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Mo(1) and one Ni(1) atom. In the second O site, O(2) is bonded to one Mo(2), one Ni(3), and two equivalent Ni(2) atoms to form distorted ONi3Mo tetrahedra that share  a cornercorner with one O(10)Ni3Se trigonal pyramid,  an edgeedge with one O(2)Ni3Mo tetrahedra, and  an edgeedge with one O(10)Ni3Se trigonal pyramid. In the third O site, O(3) is bonded in a linear geometry to one Mo(2) and one Ni(3) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mo(1), one Mo(2), one Ni(1), and one Ni(3) atom. In the fifth O site, O(5) is bonded in a linear geometry to one Mo(1) and one Ni(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ni(2), one Ni(3), and one Se(1) atom. In the seventh O site, O(7) is bonded in a distorted see-saw-like geometry to one Mo(1), one Mo(2), one Ni(1), and one Ni(2) atom. In the eighth O site, O(8) is bonded in a distorted see-saw-like geometry to one Mo(2), two equivalent Mo(1), and one Ni(1) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Mo(2) and one Ni(2) atom. In the tenth O site, O(10) is bonded to one Ni(1), one Ni(2), one Ni(3), and one Se(1) atom to form a mixture of corner and edge-sharing ONi3Se trigonal pyramids. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Ni(3) and one Se(1) atom.