Ti4Ni4Si7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to four equivalent Ni(1), one Si(4), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms to form distorted TiSi7Ni4 pentagonal bipyramids that share corners with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, corners with six equivalent Ti(1)Si7Ni4 pentagonal bipyramids, edges with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra,  an edgeedge with one Ti(1)Si7Ni4 pentagonal bipyramid, faces with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, and faces with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(3) atoms. Ni(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), two equivalent Ni(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms to form distorted NiTi4Si6Ni2 cuboctahedra that share corners with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, corners with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids, edges with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, edges with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids, faces with five equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, and faces with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(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 Ni(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Ti(1), three equivalent Ti(2), and four equivalent Ni(1) atoms. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ti(1), four equivalent Ni(1), and one Si(4) atom.
Ti4Ni4Si7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to four equivalent Ni(1), one Si(4), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(3) atoms to form distorted TiSi7Ni4 pentagonal bipyramids that share corners with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, corners with six equivalent Ti(1)Si7Ni4 pentagonal bipyramids, edges with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra,  an edgeedge with one Ti(1)Si7Ni4 pentagonal bipyramid, faces with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, and faces with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids. All Ti(1)-Ni(1) bond lengths are 3.00 Å. The Ti(1)-Si(4) bond length is 2.70 Å. Both Ti(1)-Si(1) bond lengths are 2.68 Å. Both Ti(1)-Si(2) bond lengths are 2.76 Å. Both Ti(1)-Si(3) bond lengths are 2.57 Å. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to four equivalent Ni(1), two equivalent Si(1), two equivalent Si(2), and three equivalent Si(3) atoms. All Ti(2)-Ni(1) bond lengths are 2.98 Å. Both Ti(2)-Si(1) bond lengths are 2.68 Å. Both Ti(2)-Si(2) bond lengths are 2.57 Å. There are two shorter (2.76 Å) and one longer (2.83 Å) Ti(2)-Si(3) bond length. Ni(1) is bonded to two equivalent Ti(1), two equivalent Ti(2), two equivalent Ni(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms to form distorted NiTi4Si6Ni2 cuboctahedra that share corners with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, corners with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids, edges with four equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, edges with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids, faces with five equivalent Ni(1)Ti4Si6Ni2 cuboctahedra, and faces with two equivalent Ti(1)Si7Ni4 pentagonal bipyramids. Both Ni(1)-Ni(1) bond lengths are 2.46 Å. Both Ni(1)-Si(2) bond lengths are 2.36 Å. Both Ni(1)-Si(3) bond lengths are 2.31 Å. Both Ni(1)-Si(4) bond lengths are 2.33 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(1) atoms. There is one shorter (2.45 Å) and one longer (2.47 Å) Si(1)-Si(1) bond length. 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 Ni(1) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Ti(1), three equivalent Ti(2), and four equivalent Ni(1) atoms. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ti(1), four equivalent Ni(1), and one Si(4) atom. The Si(4)-Si(4) bond length is 2.34 Å.