HoTiFe8Co3 crystallizes in the orthorhombic Imm2 space group. Ho(1) is bonded in a 20-coordinate geometry to one Ti(1), two equivalent Fe(1), two equivalent Fe(2), four equivalent Fe(3), eight equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms. Ti(1) is bonded in a 1-coordinate geometry to one Ho(1), two equivalent Fe(2), two equivalent Fe(3), four equivalent Fe(4), one Co(1), and four equivalent Co(2) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Ho(1), two equivalent Fe(3), four equivalent Fe(4), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted FeHo2Fe6Co4 cuboctahedra that share corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with six equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with six equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. In the second Fe site, Fe(2) is bonded to two equivalent Ho(1), two equivalent Ti(1), two equivalent Fe(3), four equivalent Fe(4), and two equivalent Co(2) atoms to form distorted FeHo2Ti2Fe6Co2 cuboctahedra that share corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with six equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(1)Ho2Fe6Co4 cuboctahedra, edges with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(1)Ho2Fe6Co4 cuboctahedra, faces with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with six equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. In the third Fe site, Fe(3) is bonded to two equivalent Ho(1), one Ti(1), one Fe(1), one Fe(2), four equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms to form distorted FeHo2TiFe6Co3 cuboctahedra that share corners with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with three equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with three equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with three equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent Ho(1), one Ti(1), one Fe(1), one Fe(2), two equivalent Fe(3), two equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms to form distorted FeHo2TiFe6Co3 cuboctahedra that share corners with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with three equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with ten equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(1)Ho2Fe6Co4 cuboctahedra,  an edgeedge with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with two equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, faces with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with six equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 1-coordinate geometry to one Ho(1), one Ti(1), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(4) atoms. In the second Co site, Co(2) is bonded to one Ho(1), two equivalent Ti(1), one Fe(1), one Fe(2), two equivalent Fe(3), four equivalent Fe(4), and one Co(2) atom to form distorted CoHoTi2Fe8Co cuboctahedra that share corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with six equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, corners with seven equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with two equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Co(2)HoTi2Fe8Co cuboctahedra, faces with three equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with three equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra.
HoTiFe8Co3 crystallizes in the orthorhombic Imm2 space group. Ho(1) is bonded in a 20-coordinate geometry to one Ti(1), two equivalent Fe(1), two equivalent Fe(2), four equivalent Fe(3), eight equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms. The Ho(1)-Ti(1) bond length is 3.19 Å. Both Ho(1)-Fe(1) bond lengths are 3.02 Å. Both Ho(1)-Fe(2) bond lengths are 3.03 Å. All Ho(1)-Fe(3) bond lengths are 3.01 Å. There are four shorter (3.18 Å) and four longer (3.23 Å) Ho(1)-Fe(4) bond lengths. The Ho(1)-Co(1) bond length is 2.90 Å. Both Ho(1)-Co(2) bond lengths are 3.04 Å. Ti(1) is bonded in a 1-coordinate geometry to one Ho(1), two equivalent Fe(2), two equivalent Fe(3), four equivalent Fe(4), one Co(1), and four equivalent Co(2) atoms. Both Ti(1)-Fe(2) bond lengths are 2.69 Å. Both Ti(1)-Fe(3) bond lengths are 2.60 Å. All Ti(1)-Fe(4) bond lengths are 2.65 Å. The Ti(1)-Co(1) bond length is 2.31 Å. All Ti(1)-Co(2) bond lengths are 2.84 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Ho(1), two equivalent Fe(3), four equivalent Fe(4), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted FeHo2Fe6Co4 cuboctahedra that share corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with six equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with six equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. Both Fe(1)-Fe(3) bond lengths are 2.68 Å. All Fe(1)-Fe(4) bond lengths are 2.42 Å. Both Fe(1)-Co(1) bond lengths are 2.57 Å. Both Fe(1)-Co(2) bond lengths are 2.58 Å. In the second Fe site, Fe(2) is bonded to two equivalent Ho(1), two equivalent Ti(1), two equivalent Fe(3), four equivalent Fe(4), and two equivalent Co(2) atoms to form distorted FeHo2Ti2Fe6Co2 cuboctahedra that share corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with six equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(1)Ho2Fe6Co4 cuboctahedra, edges with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(1)Ho2Fe6Co4 cuboctahedra, faces with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with six equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. Both Fe(2)-Fe(3) bond lengths are 2.63 Å. All Fe(2)-Fe(4) bond lengths are 2.45 Å. Both Fe(2)-Co(2) bond lengths are 2.61 Å. In the third Fe site, Fe(3) is bonded to two equivalent Ho(1), one Ti(1), one Fe(1), one Fe(2), four equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms to form distorted FeHo2TiFe6Co3 cuboctahedra that share corners with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with six equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with three equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with three equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with three equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. There are two shorter (2.41 Å) and two longer (2.43 Å) Fe(3)-Fe(4) bond lengths. The Fe(3)-Co(1) bond length is 2.68 Å. Both Fe(3)-Co(2) bond lengths are 2.64 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent Ho(1), one Ti(1), one Fe(1), one Fe(2), two equivalent Fe(3), two equivalent Fe(4), one Co(1), and two equivalent Co(2) atoms to form distorted FeHo2TiFe6Co3 cuboctahedra that share corners with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with three equivalent Co(2)HoTi2Fe8Co cuboctahedra, corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with ten equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  an edgeedge with one Fe(1)Ho2Fe6Co4 cuboctahedra,  an edgeedge with one Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, edges with two equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, faces with two equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, faces with four equivalent Co(2)HoTi2Fe8Co cuboctahedra, and faces with six equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. There is one shorter (2.36 Å) and one longer (2.37 Å) Fe(4)-Fe(4) bond length. The Fe(4)-Co(1) bond length is 2.55 Å. Both Fe(4)-Co(2) bond lengths are 2.58 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 1-coordinate geometry to one Ho(1), one Ti(1), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(4) atoms. In the second Co site, Co(2) is bonded to one Ho(1), two equivalent Ti(1), one Fe(1), one Fe(2), two equivalent Fe(3), four equivalent Fe(4), and one Co(2) atom to form distorted CoHoTi2Fe8Co cuboctahedra that share corners with two equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, corners with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, corners with six equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra, corners with seven equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with two equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, edges with two equivalent Co(2)HoTi2Fe8Co cuboctahedra, edges with four equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra,  a faceface with one Co(2)HoTi2Fe8Co cuboctahedra, faces with three equivalent Fe(1)Ho2Fe6Co4 cuboctahedra, faces with three equivalent Fe(2)Ho2Ti2Fe6Co2 cuboctahedra, faces with four equivalent Fe(3)Ho2TiFe6Co3 cuboctahedra, and faces with eight equivalent Fe(4)Ho2TiFe6Co3 cuboctahedra. The Co(2)-Co(2) bond length is 2.39 Å.