U4Tc7Si6 crystallizes in the cubic Im-3m space group. U(1) is bonded to six equivalent Tc(1) and six equivalent Si(1) atoms to form USi6Tc6 cuboctahedra that share corners with twelve equivalent U(1)Si6Tc6 cuboctahedra, edges with twelve equivalent Tc(1)U4Si4Tc4 cuboctahedra, faces with six equivalent U(1)Si6Tc6 cuboctahedra, faces with six equivalent Tc(1)U4Si4Tc4 cuboctahedra, and faces with two equivalent Tc(2)Si6 octahedra. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded to four equivalent U(1), four equivalent Tc(1), and four equivalent Si(1) atoms to form distorted TcU4Si4Tc4 cuboctahedra that share corners with four equivalent Tc(1)U4Si4Tc4 cuboctahedra, corners with four equivalent Tc(2)Si6 octahedra, edges with eight equivalent U(1)Si6Tc6 cuboctahedra, edges with eight equivalent Tc(1)U4Si4Tc4 cuboctahedra, faces with four equivalent U(1)Si6Tc6 cuboctahedra, and faces with six equivalent Tc(1)U4Si4Tc4 cuboctahedra. The corner-sharing octahedral tilt angles are 53°. In the second Tc site, Tc(2) is bonded to six equivalent Si(1) atoms to form TcSi6 octahedra that share corners with twenty-four equivalent Tc(1)U4Si4Tc4 cuboctahedra and faces with eight equivalent U(1)Si6Tc6 cuboctahedra. Si(1) is bonded in a 9-coordinate geometry to four equivalent U(1), one Tc(2), and four equivalent Tc(1) atoms.
U4Tc7Si6 crystallizes in the cubic Im-3m space group. U(1) is bonded to six equivalent Tc(1) and six equivalent Si(1) atoms to form USi6Tc6 cuboctahedra that share corners with twelve equivalent U(1)Si6Tc6 cuboctahedra, edges with twelve equivalent Tc(1)U4Si4Tc4 cuboctahedra, faces with six equivalent U(1)Si6Tc6 cuboctahedra, faces with six equivalent Tc(1)U4Si4Tc4 cuboctahedra, and faces with two equivalent Tc(2)Si6 octahedra. All U(1)-Tc(1) bond lengths are 2.90 Å. All U(1)-Si(1) bond lengths are 2.94 Å. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded to four equivalent U(1), four equivalent Tc(1), and four equivalent Si(1) atoms to form distorted TcU4Si4Tc4 cuboctahedra that share corners with four equivalent Tc(1)U4Si4Tc4 cuboctahedra, corners with four equivalent Tc(2)Si6 octahedra, edges with eight equivalent U(1)Si6Tc6 cuboctahedra, edges with eight equivalent Tc(1)U4Si4Tc4 cuboctahedra, faces with four equivalent U(1)Si6Tc6 cuboctahedra, and faces with six equivalent Tc(1)U4Si4Tc4 cuboctahedra. The corner-sharing octahedral tilt angles are 53°. All Tc(1)-Tc(1) bond lengths are 2.90 Å. All Tc(1)-Si(1) bond lengths are 2.56 Å. In the second Tc site, Tc(2) is bonded to six equivalent Si(1) atoms to form TcSi6 octahedra that share corners with twenty-four equivalent Tc(1)U4Si4Tc4 cuboctahedra and faces with eight equivalent U(1)Si6Tc6 cuboctahedra. All Tc(2)-Si(1) bond lengths are 2.56 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent U(1), one Tc(2), and four equivalent Tc(1) atoms.