U2Fe3Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded in a 13-coordinate geometry to one U(1), nine equivalent Fe(1), and three equivalent Si(1) atoms. Fe(1) is bonded to six equivalent U(1), four equivalent Fe(1), and two equivalent Si(1) atoms to form distorted FeU6Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U6Fe6 cuboctahedra, corners with fourteen equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Fe(1)U6Fe4Si2 cuboctahedra, faces with six equivalent Si(1)U6Fe6 cuboctahedra, and faces with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra. Si(1) is bonded to six equivalent U(1) and six equivalent Fe(1) atoms to form SiU6Fe6 cuboctahedra that share corners with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Si(1)U6Fe6 cuboctahedra, faces with two equivalent Si(1)U6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(1)U6Fe4Si2 cuboctahedra.
U2Fe3Si is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded in a 13-coordinate geometry to one U(1), nine equivalent Fe(1), and three equivalent Si(1) atoms. The U(1)-U(1) bond length is 2.71 Å. There are three shorter (2.73 Å) and six longer (2.89 Å) U(1)-Fe(1) bond lengths. All U(1)-Si(1) bond lengths are 2.99 Å. Fe(1) is bonded to six equivalent U(1), four equivalent Fe(1), and two equivalent Si(1) atoms to form distorted FeU6Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U6Fe6 cuboctahedra, corners with fourteen equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Fe(1)U6Fe4Si2 cuboctahedra, faces with six equivalent Si(1)U6Fe6 cuboctahedra, and faces with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra. There are two shorter (2.54 Å) and two longer (2.57 Å) Fe(1)-Fe(1) bond lengths. Both Fe(1)-Si(1) bond lengths are 2.35 Å. Si(1) is bonded to six equivalent U(1) and six equivalent Fe(1) atoms to form SiU6Fe6 cuboctahedra that share corners with twelve equivalent Fe(1)U6Fe4Si2 cuboctahedra, edges with six equivalent Si(1)U6Fe6 cuboctahedra, faces with two equivalent Si(1)U6Fe6 cuboctahedra, and faces with eighteen equivalent Fe(1)U6Fe4Si2 cuboctahedra.