Ba2Ni3F10 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one F(5), two equivalent F(1), two equivalent F(6), three equivalent F(3), and four equivalent F(7) atoms. In the second Ba site, Ba(2) is bonded to one F(3), one F(4), two equivalent F(1), two equivalent F(2), two equivalent F(5), two equivalent F(6), and two equivalent F(7) atoms to form distorted BaF12 cuboctahedra that share corners with four equivalent Ba(2)F12 cuboctahedra, corners with two equivalent Ni(3)F6 octahedra,  an edgeedge with one Ba(2)F12 cuboctahedra, edges with two equivalent Ni(1)F6 octahedra, faces with two equivalent Ni(3)F6 octahedra, and faces with three equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent F(4), two equivalent F(6), and two equivalent F(8) atoms to form NiF6 octahedra that share corners with two equivalent Ni(2)F6 octahedra, corners with two equivalent Ni(3)F6 octahedra, edges with two equivalent Ba(2)F12 cuboctahedra, and edges with two equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. In the second Ni site, Ni(2) is bonded to one F(3), one F(5), two equivalent F(1), and two equivalent F(6) atoms to form NiF6 octahedra that share  a cornercorner with one Ni(3)F6 octahedra, corners with two equivalent Ni(1)F6 octahedra, corners with two equivalent Ni(2)F6 octahedra, and faces with three equivalent Ba(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the third Ni site, Ni(3) is bonded to one F(5), one F(8), two equivalent F(2), and two equivalent F(7) atoms to form NiF6 octahedra that share corners with two equivalent Ba(2)F12 cuboctahedra,  a cornercorner with one Ni(2)F6 octahedra, corners with two equivalent Ni(1)F6 octahedra,  an edgeedge with one Ni(3)F6 octahedra, and faces with two equivalent Ba(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-49°. There are eight inequivalent F sites. In the first F site, F(7) is bonded in a 4-coordinate geometry to one Ba(2), two equivalent Ba(1), and one Ni(3) atom. In the second F site, F(8) is bonded in a distorted trigonal planar geometry to one Ni(3) and two equivalent Ni(1) atoms. In the third F site, F(1) is bonded in a linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ni(2) atoms. In the fourth F site, F(2) is bonded in a 4-coordinate geometry to two equivalent Ba(2) and two equivalent Ni(3) atoms. In the fifth F site, F(3) is bonded in a distorted single-bond geometry to one Ba(2), three equivalent Ba(1), and one Ni(2) atom. In the sixth F site, F(4) is bonded in a distorted L-shaped geometry to one Ba(2) and two equivalent Ni(1) atoms. In the seventh F site, F(5) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Ni(2), and one Ni(3) atom. In the eighth F site, F(6) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one Ni(2) atom.
Ba2Ni3F10 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one F(5), two equivalent F(1), two equivalent F(6), three equivalent F(3), and four equivalent F(7) atoms. The Ba(1)-F(5) bond length is 2.99 Å. Both Ba(1)-F(1) bond lengths are 3.16 Å. Both Ba(1)-F(6) bond lengths are 2.80 Å. There is one shorter (3.02 Å) and two longer (3.06 Å) Ba(1)-F(3) bond lengths. There are two shorter (2.64 Å) and two longer (2.83 Å) Ba(1)-F(7) bond lengths. In the second Ba site, Ba(2) is bonded to one F(3), one F(4), two equivalent F(1), two equivalent F(2), two equivalent F(5), two equivalent F(6), and two equivalent F(7) atoms to form distorted BaF12 cuboctahedra that share corners with four equivalent Ba(2)F12 cuboctahedra, corners with two equivalent Ni(3)F6 octahedra,  an edgeedge with one Ba(2)F12 cuboctahedra, edges with two equivalent Ni(1)F6 octahedra, faces with two equivalent Ni(3)F6 octahedra, and faces with three equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 45°. The Ba(2)-F(3) bond length is 2.79 Å. The Ba(2)-F(4) bond length is 2.86 Å. Both Ba(2)-F(1) bond lengths are 3.08 Å. Both Ba(2)-F(2) bond lengths are 2.77 Å. Both Ba(2)-F(5) bond lengths are 3.03 Å. Both Ba(2)-F(6) bond lengths are 2.85 Å. Both Ba(2)-F(7) bond lengths are 2.77 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent F(4), two equivalent F(6), and two equivalent F(8) atoms to form NiF6 octahedra that share corners with two equivalent Ni(2)F6 octahedra, corners with two equivalent Ni(3)F6 octahedra, edges with two equivalent Ba(2)F12 cuboctahedra, and edges with two equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Both Ni(1)-F(4) bond lengths are 2.01 Å. Both Ni(1)-F(6) bond lengths are 2.03 Å. Both Ni(1)-F(8) bond lengths are 2.05 Å. In the second Ni site, Ni(2) is bonded to one F(3), one F(5), two equivalent F(1), and two equivalent F(6) atoms to form NiF6 octahedra that share  a cornercorner with one Ni(3)F6 octahedra, corners with two equivalent Ni(1)F6 octahedra, corners with two equivalent Ni(2)F6 octahedra, and faces with three equivalent Ba(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-53°. The Ni(2)-F(3) bond length is 1.97 Å. The Ni(2)-F(5) bond length is 2.02 Å. Both Ni(2)-F(1) bond lengths are 2.07 Å. Both Ni(2)-F(6) bond lengths are 2.01 Å. In the third Ni site, Ni(3) is bonded to one F(5), one F(8), two equivalent F(2), and two equivalent F(7) atoms to form NiF6 octahedra that share corners with two equivalent Ba(2)F12 cuboctahedra,  a cornercorner with one Ni(2)F6 octahedra, corners with two equivalent Ni(1)F6 octahedra,  an edgeedge with one Ni(3)F6 octahedra, and faces with two equivalent Ba(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-49°. The Ni(3)-F(5) bond length is 2.11 Å. The Ni(3)-F(8) bond length is 2.04 Å. Both Ni(3)-F(2) bond lengths are 2.06 Å. Both Ni(3)-F(7) bond lengths are 1.99 Å. There are eight inequivalent F sites. In the first F site, F(7) is bonded in a 4-coordinate geometry to one Ba(2), two equivalent Ba(1), and one Ni(3) atom. In the second F site, F(8) is bonded in a distorted trigonal planar geometry to one Ni(3) and two equivalent Ni(1) atoms. In the third F site, F(1) is bonded in a linear geometry to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Ni(2) atoms. In the fourth F site, F(2) is bonded in a 4-coordinate geometry to two equivalent Ba(2) and two equivalent Ni(3) atoms. In the fifth F site, F(3) is bonded in a distorted single-bond geometry to one Ba(2), three equivalent Ba(1), and one Ni(2) atom. In the sixth F site, F(4) is bonded in a distorted L-shaped geometry to one Ba(2) and two equivalent Ni(1) atoms. In the seventh F site, F(5) is bonded in a distorted linear geometry to one Ba(1), two equivalent Ba(2), one Ni(2), and one Ni(3) atom. In the eighth F site, F(6) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(2), one Ni(1), and one Ni(2) atom.