WFeSi is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. There are five inequivalent W sites. In the first W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. In the second W site, W(2) is bonded in a 16-coordinate geometry to one W(2); three W(1,1); one Fe(3); two equivalent Fe(1); four equivalent Fe(2); two equivalent Si(1); and three equivalent Si(2) atoms. In the third W site, W(2) is bonded in a 16-coordinate geometry to one W(2); three W(1,1); one Fe(3); two equivalent Fe(1); four equivalent Fe(2); two equivalent Si(1); and three equivalent Si(2) atoms. In the fourth W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. In the fifth W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent W(1); four W(2,2); four equivalent Fe(2); and two equivalent Si(2) atoms to form FeFe4Si2W6 cuboctahedra that share corners with two equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with eight equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, edges with four equivalent Fe(3)Si6W6 cuboctahedra, faces with four equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra, and faces with eight equivalent Fe(2)Fe4Si2W6 cuboctahedra. In the second Fe site, Fe(2) is bonded to two equivalent W(1); four W(2,2); two equivalent Fe(1); two equivalent Fe(2); and two equivalent Si(2) atoms to form distorted FeFe4Si2W6 cuboctahedra that share corners with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, corners with four equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with six equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with two equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with four equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with two equivalent Fe(3)Si6W6 cuboctahedra, faces with two equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, and faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra. In the third Fe site, Fe(3) is bonded to two W(2,2); four W(1,1); two equivalent Si(2); and four equivalent Si(1) atoms to form distorted FeSi6W6 cuboctahedra that share corners with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with eight equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with two equivalent Fe(3)Si6W6 cuboctahedra, edges with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra, and faces with eight equivalent Si(1)Fe2Si4W6 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two W(2,2); four W(1,1,1); two equivalent Fe(3); two equivalent Si(1); and two equivalent Si(2) atoms to form distorted SiFe2Si4W6 cuboctahedra that share corners with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(1)Fe2Si4W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with six equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with two equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(3)Si6W6 cuboctahedra, faces with four equivalent Si(1)Fe2Si4W6 cuboctahedra, and faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra. In the second Si site, Si(2) is bonded to three W(1,1); three equivalent W(2); one Fe(1); one Fe(3); two equivalent Fe(2); and two equivalent Si(1) atoms to form distorted SiFe4Si2W6 cuboctahedra that share corners with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with two equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with six equivalent Si(2)Fe4Si2W6 cuboctahedra, faces with two equivalent Si(2)Fe4Si2W6 cuboctahedra, faces with three equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with three equivalent Fe(3)Si6W6 cuboctahedra, faces with six equivalent Fe(2)Fe4Si2W6 cuboctahedra, and faces with six equivalent Si(1)Fe2Si4W6 cuboctahedra.
WFeSi is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. There are five inequivalent W sites. In the first W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. The W(1)-W(1) bond length is 2.90 Å. There is one shorter (2.85 Å) and two longer (2.98 Å) W(1)-W(2) bond lengths. The W(1)-Fe(1) bond length is 2.70 Å. Both W(1)-Fe(2) bond lengths are 2.73 Å. Both W(1)-Fe(3) bond lengths are 2.86 Å. There is one shorter (2.82 Å) and two longer (2.83 Å) W(1)-Si(2) bond lengths. There are two shorter (2.71 Å) and two longer (2.84 Å) W(1)-Si(1) bond lengths. In the second W site, W(2) is bonded in a 16-coordinate geometry to one W(2); three W(1,1); one Fe(3); two equivalent Fe(1); four equivalent Fe(2); two equivalent Si(1); and three equivalent Si(2) atoms. The W(2)-W(2) bond length is 2.79 Å. Both W(2)-W(1) bond lengths are 2.98 Å. The W(2)-Fe(3) bond length is 2.87 Å. Both W(2)-Fe(1) bond lengths are 2.83 Å. There are two shorter (2.72 Å) and two longer (2.77 Å) W(2)-Fe(2) bond lengths. Both W(2)-Si(1) bond lengths are 2.75 Å. There is one shorter (2.67 Å) and two longer (2.86 Å) W(2)-Si(2) bond lengths. In the third W site, W(2) is bonded in a 16-coordinate geometry to one W(2); three W(1,1); one Fe(3); two equivalent Fe(1); four equivalent Fe(2); two equivalent Si(1); and three equivalent Si(2) atoms. There is one shorter (2.85 Å) and two longer (2.98 Å) W(2)-W(1,1) bond lengths. The W(2)-Fe(3) bond length is 2.87 Å. Both W(2)-Fe(1) bond lengths are 2.83 Å. There are two shorter (2.72 Å) and two longer (2.77 Å) W(2)-Fe(2) bond lengths. Both W(2)-Si(1) bond lengths are 2.75 Å. There is one shorter (2.67 Å) and two longer (2.86 Å) W(2)-Si(2) bond lengths. In the fourth W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. The W(1)-W(1) bond length is 2.90 Å. The W(1)-Fe(1) bond length is 2.70 Å. Both W(1)-Fe(2) bond lengths are 2.73 Å. Both W(1)-Fe(3) bond lengths are 2.86 Å. There is one shorter (2.82 Å) and two longer (2.83 Å) W(1)-Si(2) bond lengths. There are two shorter (2.71 Å) and two longer (2.84 Å) W(1)-Si(1) bond lengths. In the fifth W site, W(1) is bonded in a 16-coordinate geometry to one W(1), three equivalent W(2), one Fe(1), two equivalent Fe(2), two equivalent Fe(3), three equivalent Si(2), and four equivalent Si(1) atoms. The W(1)-Fe(1) bond length is 2.70 Å. Both W(1)-Fe(2) bond lengths are 2.73 Å. Both W(1)-Fe(3) bond lengths are 2.86 Å. There is one shorter (2.82 Å) and two longer (2.83 Å) W(1)-Si(2) bond lengths. There are two shorter (2.71 Å) and two longer (2.84 Å) W(1)-Si(1) bond lengths. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent W(1); four W(2,2); four equivalent Fe(2); and two equivalent Si(2) atoms to form FeFe4Si2W6 cuboctahedra that share corners with two equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with eight equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, edges with four equivalent Fe(3)Si6W6 cuboctahedra, faces with four equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra, and faces with eight equivalent Fe(2)Fe4Si2W6 cuboctahedra. There are two shorter (2.28 Å) and two longer (2.45 Å) Fe(1)-Fe(2) bond lengths. Both Fe(1)-Si(2) bond lengths are 2.33 Å. In the second Fe site, Fe(2) is bonded to two equivalent W(1); four W(2,2); two equivalent Fe(1); two equivalent Fe(2); and two equivalent Si(2) atoms to form distorted FeFe4Si2W6 cuboctahedra that share corners with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, corners with four equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with six equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with two equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with four equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with two equivalent Fe(3)Si6W6 cuboctahedra, faces with two equivalent Si(1)Fe2Si4W6 cuboctahedra, faces with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, and faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra. There is one shorter (2.36 Å) and one longer (2.56 Å) Fe(2)-Fe(2) bond length. Both Fe(2)-Si(2) bond lengths are 2.30 Å. In the third Fe site, Fe(3) is bonded to two W(2,2); four W(1,1); two equivalent Si(2); and four equivalent Si(1) atoms to form distorted FeSi6W6 cuboctahedra that share corners with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with eight equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with two equivalent Fe(3)Si6W6 cuboctahedra, edges with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra, and faces with eight equivalent Si(1)Fe2Si4W6 cuboctahedra. Both Fe(3)-Si(2) bond lengths are 2.30 Å. There are two shorter (2.35 Å) and two longer (2.38 Å) Fe(3)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two W(2,2); four W(1,1,1); two equivalent Fe(3); two equivalent Si(1); and two equivalent Si(2) atoms to form distorted SiFe2Si4W6 cuboctahedra that share corners with four equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(1)Fe2Si4W6 cuboctahedra, corners with four equivalent Si(2)Fe4Si2W6 cuboctahedra, corners with six equivalent Fe(2)Fe4Si2W6 cuboctahedra, edges with two equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with two equivalent Fe(2)Fe4Si2W6 cuboctahedra, faces with four equivalent Fe(3)Si6W6 cuboctahedra, faces with four equivalent Si(1)Fe2Si4W6 cuboctahedra, and faces with six equivalent Si(2)Fe4Si2W6 cuboctahedra. There is one shorter (2.37 Å) and one longer (2.56 Å) Si(1)-Si(1) bond length. Both Si(1)-Si(2) bond lengths are 2.54 Å. In the second Si site, Si(2) is bonded to three W(1,1); three equivalent W(2); one Fe(1); one Fe(3); two equivalent Fe(2); and two equivalent Si(1) atoms to form distorted SiFe4Si2W6 cuboctahedra that share corners with two equivalent Fe(1)Fe4Si2W6 cuboctahedra, corners with two equivalent Fe(3)Si6W6 cuboctahedra, corners with four equivalent Fe(2)Fe4Si2W6 cuboctahedra, corners with four equivalent Si(1)Fe2Si4W6 cuboctahedra, edges with six equivalent Si(2)Fe4Si2W6 cuboctahedra, faces with two equivalent Si(2)Fe4Si2W6 cuboctahedra, faces with three equivalent Fe(1)Fe4Si2W6 cuboctahedra, faces with three equivalent Fe(3)Si6W6 cuboctahedra, faces with six equivalent Fe(2)Fe4Si2W6 cuboctahedra, and faces with six equivalent Si(1)Fe2Si4W6 cuboctahedra.