Tc4Si7 crystallizes in the tetragonal P-4c2 space group. There are five inequivalent Tc sites. In the first Tc site, Tc(3) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Tc site, Tc(4) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. In the third Tc site, Tc(5) is bonded in a 10-coordinate geometry to two equivalent Si(3), four equivalent Si(1), and four equivalent Si(2) atoms. In the fourth Tc site, Tc(1) is bonded in a 8-coordinate geometry to four equivalent Si(1) and four equivalent Si(4) atoms. In the fifth Tc site, Tc(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and four equivalent Si(4) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Tc(1), one Tc(2), one Tc(3), one Tc(4), one Tc(5), one Si(1), one Si(2), one Si(3), and one Si(4) atom. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Tc(2), one Tc(3), one Tc(5), two equivalent Tc(4), one Si(1), one Si(3), one Si(4), and two equivalent Si(2) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Tc(5), two equivalent Tc(3), two equivalent Tc(4), one Si(3), two equivalent Si(1), and two equivalent Si(2) atoms. In the fourth Si site, Si(4) is bonded in a 5-coordinate geometry to one Tc(1), one Tc(3), two equivalent Tc(2), one Si(1), and one Si(2) atom.
Tc4Si7 crystallizes in the tetragonal P-4c2 space group. There are five inequivalent Tc sites. In the first Tc site, Tc(3) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. Both Tc(3)-Si(1) bond lengths are 2.69 Å. Both Tc(3)-Si(2) bond lengths are 2.41 Å. Both Tc(3)-Si(3) bond lengths are 2.51 Å. Both Tc(3)-Si(4) bond lengths are 2.42 Å. In the second Tc site, Tc(4) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms. Both Tc(4)-Si(1) bond lengths are 2.42 Å. Both Tc(4)-Si(3) bond lengths are 2.40 Å. There are two shorter (2.59 Å) and two longer (2.75 Å) Tc(4)-Si(2) bond lengths. In the third Tc site, Tc(5) is bonded in a 10-coordinate geometry to two equivalent Si(3), four equivalent Si(1), and four equivalent Si(2) atoms. Both Tc(5)-Si(3) bond lengths are 2.77 Å. All Tc(5)-Si(1) bond lengths are 2.80 Å. All Tc(5)-Si(2) bond lengths are 2.41 Å. In the fourth Tc site, Tc(1) is bonded in a 8-coordinate geometry to four equivalent Si(1) and four equivalent Si(4) atoms. All Tc(1)-Si(1) bond lengths are 2.51 Å. All Tc(1)-Si(4) bond lengths are 2.49 Å. In the fifth Tc site, Tc(2) is bonded in a 8-coordinate geometry to two equivalent Si(1), two equivalent Si(2), and four equivalent Si(4) atoms. Both Tc(2)-Si(1) bond lengths are 2.46 Å. Both Tc(2)-Si(2) bond lengths are 2.52 Å. There are two shorter (2.46 Å) and two longer (2.58 Å) Tc(2)-Si(4) bond lengths. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Tc(1), one Tc(2), one Tc(3), one Tc(4), one Tc(5), one Si(1), one Si(2), one Si(3), and one Si(4) atom. The Si(1)-Si(1) bond length is 2.79 Å. The Si(1)-Si(2) bond length is 2.54 Å. The Si(1)-Si(3) bond length is 2.79 Å. The Si(1)-Si(4) bond length is 2.70 Å. In the second Si site, Si(2) is bonded in a 10-coordinate geometry to one Tc(2), one Tc(3), one Tc(5), two equivalent Tc(4), one Si(1), one Si(3), one Si(4), and two equivalent Si(2) atoms. The Si(2)-Si(3) bond length is 2.48 Å. The Si(2)-Si(4) bond length is 2.87 Å. There is one shorter (2.63 Å) and one longer (2.78 Å) Si(2)-Si(2) bond length. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to one Tc(5), two equivalent Tc(3), two equivalent Tc(4), one Si(3), two equivalent Si(1), and two equivalent Si(2) atoms. The Si(3)-Si(3) bond length is 2.59 Å. In the fourth Si site, Si(4) is bonded in a 5-coordinate geometry to one Tc(1), one Tc(3), two equivalent Tc(2), one Si(1), and one Si(2) atom.