Ti5Si crystallizes in the trigonal R32 space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent Ti(1), six equivalent Ti(2), and three equivalent Si(1) atoms to form distorted TiTi9Si3 cuboctahedra that share corners with six equivalent Si(1)Ti12 cuboctahedra, corners with twelve equivalent Ti(1)Ti9Si3 cuboctahedra, edges with six equivalent Ti(1)Ti9Si3 cuboctahedra, faces with four equivalent Ti(1)Ti9Si3 cuboctahedra, and faces with four equivalent Si(1)Ti12 cuboctahedra. In the second Ti site, Ti(2) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(1) atoms. Si(1) is bonded to six equivalent Ti(1) and six equivalent Ti(2) atoms to form SiTi12 cuboctahedra that share corners with six equivalent Si(1)Ti12 cuboctahedra, corners with twelve equivalent Ti(1)Ti9Si3 cuboctahedra, edges with six equivalent Si(1)Ti12 cuboctahedra, and faces with eight equivalent Ti(1)Ti9Si3 cuboctahedra.
Ti5Si crystallizes in the trigonal R32 space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent Ti(1), six equivalent Ti(2), and three equivalent Si(1) atoms to form distorted TiTi9Si3 cuboctahedra that share corners with six equivalent Si(1)Ti12 cuboctahedra, corners with twelve equivalent Ti(1)Ti9Si3 cuboctahedra, edges with six equivalent Ti(1)Ti9Si3 cuboctahedra, faces with four equivalent Ti(1)Ti9Si3 cuboctahedra, and faces with four equivalent Si(1)Ti12 cuboctahedra. All Ti(1)-Ti(1) bond lengths are 2.94 Å. There are three shorter (2.83 Å) and three longer (2.88 Å) Ti(1)-Ti(2) bond lengths. All Ti(1)-Si(1) bond lengths are 2.92 Å. In the second Ti site, Ti(2) is bonded in a 10-coordinate geometry to four equivalent Ti(1), four equivalent Ti(2), and two equivalent Si(1) atoms. All Ti(2)-Ti(2) bond lengths are 2.69 Å. Both Ti(2)-Si(1) bond lengths are 2.71 Å. Si(1) is bonded to six equivalent Ti(1) and six equivalent Ti(2) atoms to form SiTi12 cuboctahedra that share corners with six equivalent Si(1)Ti12 cuboctahedra, corners with twelve equivalent Ti(1)Ti9Si3 cuboctahedra, edges with six equivalent Si(1)Ti12 cuboctahedra, and faces with eight equivalent Ti(1)Ti9Si3 cuboctahedra.