MgNi2(BiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MgO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Bi(1)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, and  a faceface with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-46°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NiO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-51°. In the second Ni site, Ni(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted BiO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with six equivalent Bi(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-66°. In the second Bi site, Bi(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted BiO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with six equivalent Bi(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, and  a faceface with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-66°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom.
MgNi2(BiO3)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MgO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Bi(1)O6 octahedra, edges with three equivalent Bi(2)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, and  a faceface with one Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-46°. The Mg(1)-O(1) bond length is 2.28 Å. The Mg(1)-O(2) bond length is 2.28 Å. The Mg(1)-O(3) bond length is 2.30 Å. The Mg(1)-O(4) bond length is 2.08 Å. The Mg(1)-O(5) bond length is 2.08 Å. The Mg(1)-O(6) bond length is 2.08 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NiO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Bi(2)O6 octahedra, edges with three equivalent Bi(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-51°. The Ni(1)-O(1) bond length is 2.26 Å. The Ni(1)-O(2) bond length is 2.27 Å. The Ni(1)-O(3) bond length is 2.25 Å. The Ni(1)-O(4) bond length is 2.12 Å. The Ni(1)-O(5) bond length is 2.13 Å. The Ni(1)-O(6) bond length is 2.12 Å. In the second Ni site, Ni(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The Ni(2)-O(1) bond length is 1.94 Å. The Ni(2)-O(2) bond length is 1.94 Å. The Ni(2)-O(3) bond length is 1.94 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted BiO6 octahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with six equivalent Bi(2)O6 octahedra, edges with three equivalent Ni(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-66°. The Bi(1)-O(1) bond length is 2.56 Å. The Bi(1)-O(2) bond length is 2.57 Å. The Bi(1)-O(3) bond length is 2.56 Å. The Bi(1)-O(4) bond length is 2.23 Å. The Bi(1)-O(5) bond length is 2.23 Å. The Bi(1)-O(6) bond length is 2.23 Å. In the second Bi site, Bi(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted BiO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with six equivalent Bi(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, and  a faceface with one Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-66°. The Bi(2)-O(1) bond length is 2.44 Å. The Bi(2)-O(2) bond length is 2.43 Å. The Bi(2)-O(3) bond length is 2.43 Å. The Bi(2)-O(4) bond length is 2.33 Å. The Bi(2)-O(5) bond length is 2.33 Å. The Bi(2)-O(6) bond length is 2.33 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), one Ni(1), one Ni(2), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(2) atom.