ErH(SO4)2 crystallizes in the monoclinic P2_1/c space group. Er(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form ErO7 pentagonal bipyramids that share corners with three equivalent S(1)O4 tetrahedra and corners with four equivalent S(2)O4 tetrahedra. H(1) is bonded in a single-bond geometry to one O(6) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form SO4 tetrahedra that share corners with three equivalent Er(1)O7 pentagonal bipyramids. In the second S site, S(2) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form SO4 tetrahedra that share corners with four equivalent Er(1)O7 pentagonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Er(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Er(1) and one S(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Er(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Er(1) and one S(2) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Er(1) and one S(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one H(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one S(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one S(2) atom.
ErH(SO4)2 crystallizes in the monoclinic P2_1/c space group. Er(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form ErO7 pentagonal bipyramids that share corners with three equivalent S(1)O4 tetrahedra and corners with four equivalent S(2)O4 tetrahedra. The Er(1)-O(1) bond length is 2.26 Å. The Er(1)-O(2) bond length is 2.30 Å. The Er(1)-O(3) bond length is 2.31 Å. The Er(1)-O(4) bond length is 2.29 Å. The Er(1)-O(5) bond length is 2.27 Å. The Er(1)-O(7) bond length is 2.35 Å. The Er(1)-O(8) bond length is 2.27 Å. H(1) is bonded in a single-bond geometry to one O(6) atom. The H(1)-O(6) bond length is 1.00 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form SO4 tetrahedra that share corners with three equivalent Er(1)O7 pentagonal bipyramids. The S(1)-O(1) bond length is 1.47 Å. The S(1)-O(3) bond length is 1.45 Å. The S(1)-O(6) bond length is 1.57 Å. The S(1)-O(7) bond length is 1.46 Å. In the second S site, S(2) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form SO4 tetrahedra that share corners with four equivalent Er(1)O7 pentagonal bipyramids. The S(2)-O(2) bond length is 1.47 Å. The S(2)-O(4) bond length is 1.48 Å. The S(2)-O(5) bond length is 1.47 Å. The S(2)-O(8) bond length is 1.52 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Er(1) and one S(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Er(1) and one S(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Er(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Er(1) and one S(2) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Er(1) and one S(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one H(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one S(1) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one S(2) atom.