Ho2Ni(B2O5)2 is Esseneite-like structured and crystallizes in the monoclinic P2_1/c space group. Ho(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent B(2)O4 tetrahedra, corners with four equivalent B(1)O4 tetrahedra, and edges with two equivalent B(2)O4 tetrahedra. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form BO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with three equivalent B(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 61-70°. In the second B site, B(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form BO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with three equivalent B(1)O4 tetrahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ho(1), one Ni(1), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ho(1), one Ni(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ho(1), one Ni(1), one B(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Ho(1), one B(1), and one B(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one B(1) atom.
Ho2Ni(B2O5)2 is Esseneite-like structured and crystallizes in the monoclinic P2_1/c space group. Ho(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms. The Ho(1)-O(2) bond length is 2.36 Å. The Ho(1)-O(3) bond length is 2.39 Å. There is one shorter (2.34 Å) and one longer (2.43 Å) Ho(1)-O(1) bond length. Both Ho(1)-O(4) bond lengths are 2.52 Å. There is one shorter (2.22 Å) and one longer (2.24 Å) Ho(1)-O(5) bond length. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent B(2)O4 tetrahedra, corners with four equivalent B(1)O4 tetrahedra, and edges with two equivalent B(2)O4 tetrahedra. Both Ni(1)-O(1) bond lengths are 2.01 Å. Both Ni(1)-O(2) bond lengths are 2.07 Å. Both Ni(1)-O(3) bond lengths are 2.16 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form BO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with three equivalent B(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 61-70°. The B(1)-O(2) bond length is 1.53 Å. The B(1)-O(3) bond length is 1.53 Å. The B(1)-O(4) bond length is 1.51 Å. The B(1)-O(5) bond length is 1.42 Å. In the second B site, B(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form BO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra, corners with three equivalent B(1)O4 tetrahedra, and  an edgeedge with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 61°. The B(2)-O(1) bond length is 1.42 Å. The B(2)-O(2) bond length is 1.52 Å. The B(2)-O(3) bond length is 1.53 Å. The B(2)-O(4) bond length is 1.52 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ho(1), one Ni(1), and one B(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ho(1), one Ni(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ho(1), one Ni(1), one B(1), and one B(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to two equivalent Ho(1), one B(1), and one B(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Ho(1) and one B(1) atom.