Er2Mo3H2Se2O17 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(10), one O(11), one O(12), one O(3), and four equivalent O(1) atoms to form distorted edge-sharing ErO8 hexagonal bipyramids. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(2), one O(5), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 37-50°. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(3), one O(9), and two equivalent O(8) atoms. H(1) is bonded in a single-bond geometry to one O(12) atom. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(2) and two equivalent O(1) atoms. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one O(3) and two equivalent O(4) atoms. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Er(2) and one Se(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one Mo(2), and one Se(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Er(2), one Mo(1), and one Se(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Er(2) and two equivalent Mo(1) atoms. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Er(2) and one Mo(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Er(2) and one Mo(1) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Mo(1) and one Mo(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Mo(2) and two equivalent Mo(1) atoms. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Er(1) and one Mo(2) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Er(1) and one Mo(2) atom. In the twelfth O site, O(12) is bonded in a distorted water-like geometry to one Er(1) and two equivalent H(1) atoms.
Er2Mo3H2Se2O17 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(10), one O(11), one O(12), one O(3), and four equivalent O(1) atoms to form distorted edge-sharing ErO8 hexagonal bipyramids. The Er(1)-O(10) bond length is 2.30 Å. The Er(1)-O(11) bond length is 2.43 Å. The Er(1)-O(12) bond length is 2.31 Å. The Er(1)-O(3) bond length is 2.39 Å. There are two shorter (2.37 Å) and two longer (2.43 Å) Er(1)-O(1) bond lengths. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(2), one O(5), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. The Er(2)-O(2) bond length is 2.16 Å. The Er(2)-O(5) bond length is 2.39 Å. Both Er(2)-O(4) bond lengths are 2.49 Å. Both Er(2)-O(6) bond lengths are 2.39 Å. Both Er(2)-O(7) bond lengths are 2.33 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 37-50°. The Mo(1)-O(4) bond length is 2.27 Å. The Mo(1)-O(5) bond length is 1.98 Å. The Mo(1)-O(6) bond length is 1.77 Å. The Mo(1)-O(7) bond length is 1.76 Å. The Mo(1)-O(8) bond length is 2.12 Å. The Mo(1)-O(9) bond length is 1.96 Å. In the second Mo site, Mo(2) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(3), one O(9), and two equivalent O(8) atoms. The Mo(2)-O(10) bond length is 1.78 Å. The Mo(2)-O(11) bond length is 1.77 Å. The Mo(2)-O(3) bond length is 2.37 Å. The Mo(2)-O(9) bond length is 2.22 Å. Both Mo(2)-O(8) bond lengths are 1.92 Å. H(1) is bonded in a single-bond geometry to one O(12) atom. The H(1)-O(12) bond length is 0.99 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(2) and two equivalent O(1) atoms. The Se(1)-O(2) bond length is 1.71 Å. Both Se(1)-O(1) bond lengths are 1.76 Å. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one O(3) and two equivalent O(4) atoms. The Se(2)-O(3) bond length is 1.71 Å. Both Se(2)-O(4) bond lengths are 1.75 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Er(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Er(2) and one Se(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Er(1), one Mo(2), and one Se(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Er(2), one Mo(1), and one Se(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Er(2) and two equivalent Mo(1) atoms. In the sixth O site, O(6) is bonded in a distorted linear geometry to one Er(2) and one Mo(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Er(2) and one Mo(1) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Mo(1) and one Mo(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Mo(2) and two equivalent Mo(1) atoms. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Er(1) and one Mo(2) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Er(1) and one Mo(2) atom. In the twelfth O site, O(12) is bonded in a distorted water-like geometry to one Er(1) and two equivalent H(1) atoms.