Ca2HoMn4BiO12 crystallizes in the monoclinic Pm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(6), and two equivalent O(8) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms. Ho(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(6), and two equivalent O(8) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with three equivalent Mn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-45°. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form distorted MnO5 trigonal bipyramids that share corners with three equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 37-43°. Bi(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(7) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), two equivalent Mn(2), and one Bi(1) atom to form a mixture of distorted edge and corner-sharing OCaMn2Bi tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Mn(1), and one Bi(1) atom. In the third O site, O(3) is bonded to one Ca(2), one Ho(1), and two equivalent Mn(2) atoms to form OCaHoMn2 trigonal pyramids that share corners with two equivalent O(4)CaHoMn2 tetrahedra, corners with two equivalent O(1)CaMn2Bi tetrahedra, and corners with four equivalent O(6)CaHoMn2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(2), one Ho(1), and two equivalent Mn(1) atoms to form a mixture of edge and corner-sharing OCaHoMn2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(2), one Mn(1), one Mn(2), and one Bi(1) atom. In the sixth O site, O(6) is bonded to one Ca(1), one Ho(1), one Mn(1), and one Mn(2) atom to form distorted OCaHoMn2 trigonal pyramids that share corners with two equivalent O(3)CaHoMn2 trigonal pyramids, corners with two equivalent O(6)CaHoMn2 trigonal pyramids,  an edgeedge with one O(4)CaHoMn2 tetrahedra, and  an edgeedge with one O(1)CaMn2Bi tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), one Mn(1), one Mn(2), and one Bi(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), one Ho(1), and one Mn(1) atom.
Ca2HoMn4BiO12 crystallizes in the monoclinic Pm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(6), and two equivalent O(8) atoms. The Ca(1)-O(1) bond length is 2.34 Å. The Ca(1)-O(2) bond length is 2.61 Å. Both Ca(1)-O(6) bond lengths are 2.57 Å. Both Ca(1)-O(8) bond lengths are 2.37 Å. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(3), one O(4), two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms. The Ca(2)-O(3) bond length is 2.42 Å. The Ca(2)-O(4) bond length is 2.25 Å. Both Ca(2)-O(5) bond lengths are 2.45 Å. Both Ca(2)-O(7) bond lengths are 2.54 Å. Both Ca(2)-O(8) bond lengths are 2.84 Å. Ho(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(6), and two equivalent O(8) atoms. The Ho(1)-O(3) bond length is 2.33 Å. The Ho(1)-O(4) bond length is 2.26 Å. Both Ho(1)-O(6) bond lengths are 2.28 Å. Both Ho(1)-O(8) bond lengths are 2.28 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra and corners with three equivalent Mn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-45°. The Mn(1)-O(2) bond length is 1.97 Å. The Mn(1)-O(4) bond length is 1.91 Å. The Mn(1)-O(5) bond length is 2.61 Å. The Mn(1)-O(6) bond length is 1.94 Å. The Mn(1)-O(7) bond length is 2.50 Å. The Mn(1)-O(8) bond length is 1.91 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form distorted MnO5 trigonal bipyramids that share corners with three equivalent Mn(1)O6 octahedra and corners with two equivalent Mn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 37-43°. The Mn(2)-O(1) bond length is 1.91 Å. The Mn(2)-O(3) bond length is 1.94 Å. The Mn(2)-O(5) bond length is 1.97 Å. The Mn(2)-O(6) bond length is 2.14 Å. The Mn(2)-O(7) bond length is 1.98 Å. Bi(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(5), and two equivalent O(7) atoms. The Bi(1)-O(1) bond length is 2.29 Å. The Bi(1)-O(2) bond length is 2.21 Å. Both Bi(1)-O(5) bond lengths are 2.23 Å. Both Bi(1)-O(7) bond lengths are 2.20 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), two equivalent Mn(2), and one Bi(1) atom to form a mixture of distorted edge and corner-sharing OCaMn2Bi tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Mn(1), and one Bi(1) atom. In the third O site, O(3) is bonded to one Ca(2), one Ho(1), and two equivalent Mn(2) atoms to form OCaHoMn2 trigonal pyramids that share corners with two equivalent O(4)CaHoMn2 tetrahedra, corners with two equivalent O(1)CaMn2Bi tetrahedra, and corners with four equivalent O(6)CaHoMn2 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(2), one Ho(1), and two equivalent Mn(1) atoms to form a mixture of edge and corner-sharing OCaHoMn2 tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(2), one Mn(1), one Mn(2), and one Bi(1) atom. In the sixth O site, O(6) is bonded to one Ca(1), one Ho(1), one Mn(1), and one Mn(2) atom to form distorted OCaHoMn2 trigonal pyramids that share corners with two equivalent O(3)CaHoMn2 trigonal pyramids, corners with two equivalent O(6)CaHoMn2 trigonal pyramids,  an edgeedge with one O(4)CaHoMn2 tetrahedra, and  an edgeedge with one O(1)CaMn2Bi tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Ca(2), one Mn(1), one Mn(2), and one Bi(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(2), one Ho(1), and one Mn(1) atom.