Cs5CaNi4F15 crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to three equivalent F(1) and nine equivalent F(2) atoms to form CsF12 cuboctahedra that share corners with three equivalent Cs(2)F12 cuboctahedra, corners with six equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Ni(2)F6 octahedra,  a faceface with one Cs(3)F12 cuboctahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Ca(1)F6 octahedra, and faces with four equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Cs site, Cs(2) is bonded to three equivalent F(2), three equivalent F(3), and six equivalent F(1) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with six equivalent Cs(2)F12 cuboctahedra, corners with three equivalent Ni(2)F6 octahedra,  a faceface with one Cs(2)F12 cuboctahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Cs(3)F12 cuboctahedra,  a faceface with one Ca(1)F6 octahedra, faces with three equivalent Ni(1)F6 octahedra, and faces with three equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 8°. In the third Cs site, Cs(3) is bonded to six equivalent F(1) and six equivalent F(3) atoms to form distorted CsF12 cuboctahedra that share corners with six equivalent Cs(3)F12 cuboctahedra, corners with six equivalent Ni(1)F6 octahedra, faces with two equivalent Cs(1)F12 cuboctahedra, faces with six equivalent Cs(2)F12 cuboctahedra, and faces with six equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 9°. Ca(1) is bonded to six equivalent F(2) atoms to form CaF6 octahedra that share corners with six equivalent Ni(1)F6 octahedra, faces with two equivalent Cs(2)F12 cuboctahedra, and faces with six equivalent Cs(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form NiF6 octahedra that share corners with three equivalent Cs(3)F12 cuboctahedra, corners with three equivalent Ca(1)F6 octahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with four equivalent Cs(1)F12 cuboctahedra, and  a faceface with one Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second Ni site, Ni(2) is bonded to three equivalent F(1) and three equivalent F(3) atoms to form NiF6 octahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Cs(3)F12 cuboctahedra,  a faceface with one Ni(1)F6 octahedra, and  a faceface with one Ni(2)F6 octahedra. There are three inequivalent F sites. In the first F site, F(1) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(3), two equivalent Cs(2), one Ni(1), and one Ni(2) atom. In the second F site, F(2) is bonded in a distorted linear geometry to one Cs(2), three equivalent Cs(1), one Ca(1), and one Ni(1) atom. In the third F site, F(3) is bonded in a distorted L-shaped geometry to two equivalent Cs(2), two equivalent Cs(3), and two equivalent Ni(2) atoms.
Cs5CaNi4F15 crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to three equivalent F(1) and nine equivalent F(2) atoms to form CsF12 cuboctahedra that share corners with three equivalent Cs(2)F12 cuboctahedra, corners with six equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Ni(2)F6 octahedra,  a faceface with one Cs(3)F12 cuboctahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Ca(1)F6 octahedra, and faces with four equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles are 7°. All Cs(1)-F(1) bond lengths are 3.08 Å. There are six shorter (3.17 Å) and three longer (3.25 Å) Cs(1)-F(2) bond lengths. In the second Cs site, Cs(2) is bonded to three equivalent F(2), three equivalent F(3), and six equivalent F(1) atoms to form distorted CsF12 cuboctahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with six equivalent Cs(2)F12 cuboctahedra, corners with three equivalent Ni(2)F6 octahedra,  a faceface with one Cs(2)F12 cuboctahedra, faces with three equivalent Cs(1)F12 cuboctahedra, faces with three equivalent Cs(3)F12 cuboctahedra,  a faceface with one Ca(1)F6 octahedra, faces with three equivalent Ni(1)F6 octahedra, and faces with three equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 8°. All Cs(2)-F(2) bond lengths are 3.31 Å. All Cs(2)-F(3) bond lengths are 3.21 Å. All Cs(2)-F(1) bond lengths are 3.18 Å. In the third Cs site, Cs(3) is bonded to six equivalent F(1) and six equivalent F(3) atoms to form distorted CsF12 cuboctahedra that share corners with six equivalent Cs(3)F12 cuboctahedra, corners with six equivalent Ni(1)F6 octahedra, faces with two equivalent Cs(1)F12 cuboctahedra, faces with six equivalent Cs(2)F12 cuboctahedra, and faces with six equivalent Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 9°. All Cs(3)-F(1) bond lengths are 3.39 Å. All Cs(3)-F(3) bond lengths are 3.17 Å. Ca(1) is bonded to six equivalent F(2) atoms to form CaF6 octahedra that share corners with six equivalent Ni(1)F6 octahedra, faces with two equivalent Cs(2)F12 cuboctahedra, and faces with six equivalent Cs(1)F12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Ca(1)-F(2) bond lengths are 2.29 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to three equivalent F(1) and three equivalent F(2) atoms to form NiF6 octahedra that share corners with three equivalent Cs(3)F12 cuboctahedra, corners with three equivalent Ca(1)F6 octahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with four equivalent Cs(1)F12 cuboctahedra, and  a faceface with one Ni(2)F6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Ni(1)-F(1) bond lengths are 2.09 Å. All Ni(1)-F(2) bond lengths are 2.03 Å. In the second Ni site, Ni(2) is bonded to three equivalent F(1) and three equivalent F(3) atoms to form NiF6 octahedra that share corners with three equivalent Cs(1)F12 cuboctahedra, corners with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Cs(2)F12 cuboctahedra, faces with three equivalent Cs(3)F12 cuboctahedra,  a faceface with one Ni(1)F6 octahedra, and  a faceface with one Ni(2)F6 octahedra. All Ni(2)-F(1) bond lengths are 2.02 Å. All Ni(2)-F(3) bond lengths are 2.05 Å. There are three inequivalent F sites. In the first F site, F(1) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(3), two equivalent Cs(2), one Ni(1), and one Ni(2) atom. In the second F site, F(2) is bonded in a distorted linear geometry to one Cs(2), three equivalent Cs(1), one Ca(1), and one Ni(1) atom. In the third F site, F(3) is bonded in a distorted L-shaped geometry to two equivalent Cs(2), two equivalent Cs(3), and two equivalent Ni(2) atoms.