Ba4Ca4Cu6Hg2O17 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(4), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to four equivalent O(3) atoms. Hg(1) is bonded in a linear geometry to two equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and one Hg(1) atom. In the second O site, O(2) is bonded to one Ba(1), one Ba(2), one Ca(1), one Ca(2), and two equivalent Cu(1) atoms to form distorted OBa2Ca2Cu2 octahedra that share corners with two equivalent O(2)Ba2Ca2Cu2 octahedra, corners with six equivalent O(3)Ca4Cu2 octahedra,  an edgeedge with one O(3)Ca4Cu2 octahedra, edges with two equivalent O(2)Ba2Ca2Cu2 octahedra, and faces with four equivalent O(2)Ba2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 2-67°. In the third O site, O(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), and two equivalent Cu(2) atoms to form OCa4Cu2 octahedra that share corners with two equivalent O(3)Ca4Cu2 octahedra, corners with twelve equivalent O(2)Ba2Ca2Cu2 octahedra, edges with two equivalent O(2)Ba2Ca2Cu2 octahedra, edges with two equivalent O(3)Ca4Cu2 octahedra, and faces with four equivalent O(3)Ca4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(2) atoms.
Ba4Ca4Cu6Hg2O17 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. All Ba(1)-O(1) bond lengths are 2.83 Å. All Ba(1)-O(2) bond lengths are 2.83 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(4), four equivalent O(1), and four equivalent O(2) atoms. The Ba(2)-O(4) bond length is 2.63 Å. All Ba(2)-O(1) bond lengths are 2.79 Å. All Ba(2)-O(2) bond lengths are 2.98 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All Ca(1)-O(2) bond lengths are 2.44 Å. All Ca(1)-O(3) bond lengths are 2.52 Å. In the second Ca site, Ca(2) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All Ca(2)-O(2) bond lengths are 2.44 Å. All Ca(2)-O(3) bond lengths are 2.54 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Cu(1)-O(2) bond lengths are 1.93 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to four equivalent O(3) atoms. All Cu(2)-O(3) bond lengths are 1.93 Å. Hg(1) is bonded in a linear geometry to two equivalent O(1) atoms. Both Hg(1)-O(1) bond lengths are 2.06 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), and one Hg(1) atom. In the second O site, O(2) is bonded to one Ba(1), one Ba(2), one Ca(1), one Ca(2), and two equivalent Cu(1) atoms to form distorted OBa2Ca2Cu2 octahedra that share corners with two equivalent O(2)Ba2Ca2Cu2 octahedra, corners with six equivalent O(3)Ca4Cu2 octahedra,  an edgeedge with one O(3)Ca4Cu2 octahedra, edges with two equivalent O(2)Ba2Ca2Cu2 octahedra, and faces with four equivalent O(2)Ba2Ca2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 2-67°. In the third O site, O(3) is bonded to two equivalent Ca(1), two equivalent Ca(2), and two equivalent Cu(2) atoms to form OCa4Cu2 octahedra that share corners with two equivalent O(3)Ca4Cu2 octahedra, corners with twelve equivalent O(2)Ba2Ca2Cu2 octahedra, edges with two equivalent O(2)Ba2Ca2Cu2 octahedra, edges with two equivalent O(3)Ca4Cu2 octahedra, and faces with four equivalent O(3)Ca4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-67°. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(2) atoms.