Ti4Co4Si7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 7-coordinate geometry to four equivalent Co(1), two equivalent Si(2), two equivalent Si(4), and three equivalent Si(1) atoms. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to four equivalent Co(1), one Si(3), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. Co(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), two equivalent Co(1), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms to form a mixture of distorted edge, corner, and face-sharing CoTi4Co2Si6 cuboctahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ti(2), three equivalent Ti(1), and four equivalent Co(1) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent Ti(1), two equivalent Ti(2), and four equivalent Co(1) atoms. In the third Si site, Si(3) is bonded in a 6-coordinate geometry to one Ti(2), four equivalent Co(1), and one Si(3) atom. In the fourth Si site, Si(4) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(4) atoms.
Ti4Co4Si7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 7-coordinate geometry to four equivalent Co(1), two equivalent Si(2), two equivalent Si(4), and three equivalent Si(1) atoms. All Ti(1)-Co(1) bond lengths are 2.94 Å. Both Ti(1)-Si(2) bond lengths are 2.61 Å. Both Ti(1)-Si(4) bond lengths are 2.68 Å. There are two shorter (2.75 Å) and one longer (2.76 Å) Ti(1)-Si(1) bond length. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to four equivalent Co(1), one Si(3), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. All Ti(2)-Co(1) bond lengths are 2.96 Å. The Ti(2)-Si(3) bond length is 2.63 Å. Both Ti(2)-Si(1) bond lengths are 2.58 Å. Both Ti(2)-Si(2) bond lengths are 2.75 Å. Both Ti(2)-Si(4) bond lengths are 2.70 Å. Co(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), two equivalent Co(1), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms to form a mixture of distorted edge, corner, and face-sharing CoTi4Co2Si6 cuboctahedra. Both Co(1)-Co(1) bond lengths are 2.44 Å. Both Co(1)-Si(1) bond lengths are 2.28 Å. Both Co(1)-Si(2) bond lengths are 2.33 Å. Both Co(1)-Si(3) bond lengths are 2.33 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ti(2), three equivalent Ti(1), and four equivalent Co(1) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to two equivalent Ti(1), two equivalent Ti(2), and four equivalent Co(1) atoms. In the third Si site, Si(3) is bonded in a 6-coordinate geometry to one Ti(2), four equivalent Co(1), and one Si(3) atom. The Si(3)-Si(3) bond length is 2.35 Å. In the fourth Si site, Si(4) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(4) atoms. There is one shorter (2.44 Å) and one longer (2.45 Å) Si(4)-Si(4) bond length.