Nb4Co3Si7 crystallizes in the orthorhombic F222 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 7-coordinate geometry to two equivalent Si(4), two equivalent Si(5), and three equivalent Si(2) atoms. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to two equivalent Co(3), two equivalent Si(4), two equivalent Si(5), two equivalent Si(6), and three equivalent Si(3) atoms. In the third Nb site, Nb(3) is bonded in a 5-coordinate geometry to one Co(1), one Co(3), one Si(2), one Si(3), one Si(6), two equivalent Si(4), and two equivalent Si(5) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 10-coordinate geometry to two equivalent Nb(3), two equivalent Co(2), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the second Co site, Co(2) is bonded in a 4-coordinate geometry to two equivalent Co(1), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the third Co site, Co(3) is bonded in a 12-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Si(1), two equivalent Si(3), two equivalent Si(4), and two equivalent Si(6) atoms. There are six inequivalent Si sites. In the first Si site, Si(5) is bonded in a 10-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), four equivalent Nb(3), and two equivalent Si(5) atoms. In the second Si site, Si(6) is bonded in a 12-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Co(3), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the third Si site, Si(1) is bonded in a 12-coordinate geometry to two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(6) atoms. In the fourth Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Nb(3), three equivalent Nb(1), two equivalent Co(1), and two equivalent Co(2) atoms. In the fifth Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Nb(3), three equivalent Nb(2), two equivalent Co(3), and two equivalent Si(6) atoms. In the sixth Si site, Si(4) is bonded in a 9-coordinate geometry to one Nb(1), one Nb(2), two equivalent Nb(3), one Co(1), one Co(2), one Co(3), one Si(1), and one Si(6) atom.
Nb4Co3Si7 crystallizes in the orthorhombic F222 space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 7-coordinate geometry to two equivalent Si(4), two equivalent Si(5), and three equivalent Si(2) atoms. Both Nb(1)-Si(4) bond lengths are 2.54 Å. Both Nb(1)-Si(5) bond lengths are 2.73 Å. There is one shorter (2.80 Å) and two longer (2.85 Å) Nb(1)-Si(2) bond lengths. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to two equivalent Co(3), two equivalent Si(4), two equivalent Si(5), two equivalent Si(6), and three equivalent Si(3) atoms. Both Nb(2)-Co(3) bond lengths are 2.94 Å. Both Nb(2)-Si(4) bond lengths are 2.70 Å. Both Nb(2)-Si(5) bond lengths are 2.67 Å. Both Nb(2)-Si(6) bond lengths are 3.04 Å. There is one shorter (2.71 Å) and two longer (2.76 Å) Nb(2)-Si(3) bond lengths. In the third Nb site, Nb(3) is bonded in a 5-coordinate geometry to one Co(1), one Co(3), one Si(2), one Si(3), one Si(6), two equivalent Si(4), and two equivalent Si(5) atoms. The Nb(3)-Co(1) bond length is 3.06 Å. The Nb(3)-Co(3) bond length is 2.93 Å. The Nb(3)-Si(2) bond length is 2.66 Å. The Nb(3)-Si(3) bond length is 2.60 Å. The Nb(3)-Si(6) bond length is 2.90 Å. There is one shorter (2.67 Å) and one longer (2.85 Å) Nb(3)-Si(4) bond length. There is one shorter (2.72 Å) and one longer (2.77 Å) Nb(3)-Si(5) bond length. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 10-coordinate geometry to two equivalent Nb(3), two equivalent Co(2), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. Both Co(1)-Co(2) bond lengths are 2.55 Å. Both Co(1)-Si(1) bond lengths are 2.37 Å. Both Co(1)-Si(2) bond lengths are 2.73 Å. Both Co(1)-Si(4) bond lengths are 2.31 Å. In the second Co site, Co(2) is bonded in a 4-coordinate geometry to two equivalent Co(1), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. Both Co(2)-Si(1) bond lengths are 2.85 Å. Both Co(2)-Si(2) bond lengths are 2.23 Å. Both Co(2)-Si(4) bond lengths are 2.28 Å. In the third Co site, Co(3) is bonded in a 12-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Si(1), two equivalent Si(3), two equivalent Si(4), and two equivalent Si(6) atoms. Both Co(3)-Si(1) bond lengths are 2.98 Å. Both Co(3)-Si(3) bond lengths are 2.31 Å. Both Co(3)-Si(4) bond lengths are 2.29 Å. Both Co(3)-Si(6) bond lengths are 2.48 Å. There are six inequivalent Si sites. In the first Si site, Si(5) is bonded in a 10-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), four equivalent Nb(3), and two equivalent Si(5) atoms. There is one shorter (2.44 Å) and one longer (2.51 Å) Si(5)-Si(5) bond length. In the second Si site, Si(6) is bonded in a 12-coordinate geometry to two equivalent Nb(2), two equivalent Nb(3), two equivalent Co(3), two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. Both Si(6)-Si(1) bond lengths are 2.88 Å. Both Si(6)-Si(3) bond lengths are 2.43 Å. Both Si(6)-Si(4) bond lengths are 2.39 Å. In the third Si site, Si(1) is bonded in a 12-coordinate geometry to two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), two equivalent Si(1), two equivalent Si(4), and two equivalent Si(6) atoms. There is one shorter (2.35 Å) and one longer (2.60 Å) Si(1)-Si(1) bond length. Both Si(1)-Si(4) bond lengths are 2.58 Å. In the fourth Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Nb(3), three equivalent Nb(1), two equivalent Co(1), and two equivalent Co(2) atoms. In the fifth Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Nb(3), three equivalent Nb(2), two equivalent Co(3), and two equivalent Si(6) atoms. In the sixth Si site, Si(4) is bonded in a 9-coordinate geometry to one Nb(1), one Nb(2), two equivalent Nb(3), one Co(1), one Co(2), one Co(3), one Si(1), and one Si(6) atom.