Co2NbSn crystallizes in the orthorhombic Pmma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Co(1), four equivalent Co(2), two equivalent Sn(1), and two equivalent Sn(2) atoms to form distorted NbCo8Sn4 cuboctahedra that share corners with two equivalent Nb(1)Co8Sn4 cuboctahedra, corners with eight equivalent Sn(2)Nb4Co8 cuboctahedra, edges with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Sn(2)Nb4Co8 cuboctahedra, and faces with four equivalent Sn(1)Nb4Co8 cuboctahedra. In the second Nb site, Nb(2) is bonded in a 12-coordinate geometry to four equivalent Co(1), four equivalent Co(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a distorted body-centered cubic geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. In the second Co site, Co(2) is bonded in a 8-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), four equivalent Co(1), and four equivalent Co(2) atoms to form distorted SnNb4Co8 cuboctahedra that share corners with four equivalent Sn(1)Nb4Co8 cuboctahedra, edges with four equivalent Sn(1)Nb4Co8 cuboctahedra, edges with four equivalent Sn(2)Nb4Co8 cuboctahedra, faces with four equivalent Nb(1)Co8Sn4 cuboctahedra, and faces with four equivalent Sn(2)Nb4Co8 cuboctahedra. In the second Sn site, Sn(2) is bonded to two equivalent Nb(1), two equivalent Nb(2), four equivalent Co(1), and four equivalent Co(2) atoms to form distorted SnNb4Co8 cuboctahedra that share corners with two equivalent Sn(2)Nb4Co8 cuboctahedra, corners with eight equivalent Nb(1)Co8Sn4 cuboctahedra, edges with two equivalent Sn(2)Nb4Co8 cuboctahedra, edges with four equivalent Sn(1)Nb4Co8 cuboctahedra, faces with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Sn(2)Nb4Co8 cuboctahedra, and faces with four equivalent Sn(1)Nb4Co8 cuboctahedra.
Co2NbSn crystallizes in the orthorhombic Pmma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to four equivalent Co(1), four equivalent Co(2), two equivalent Sn(1), and two equivalent Sn(2) atoms to form distorted NbCo8Sn4 cuboctahedra that share corners with two equivalent Nb(1)Co8Sn4 cuboctahedra, corners with eight equivalent Sn(2)Nb4Co8 cuboctahedra, edges with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Sn(2)Nb4Co8 cuboctahedra, and faces with four equivalent Sn(1)Nb4Co8 cuboctahedra. All Nb(1)-Co(1) bond lengths are 2.69 Å. All Nb(1)-Co(2) bond lengths are 2.67 Å. Both Nb(1)-Sn(1) bond lengths are 2.99 Å. Both Nb(1)-Sn(2) bond lengths are 2.96 Å. In the second Nb site, Nb(2) is bonded in a 12-coordinate geometry to four equivalent Co(1), four equivalent Co(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. All Nb(2)-Co(1) bond lengths are 2.66 Å. There are two shorter (2.58 Å) and two longer (2.81 Å) Nb(2)-Co(2) bond lengths. Both Nb(2)-Sn(1) bond lengths are 2.96 Å. Both Nb(2)-Sn(2) bond lengths are 3.03 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a distorted body-centered cubic geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. Both Co(1)-Sn(1) bond lengths are 2.67 Å. Both Co(1)-Sn(2) bond lengths are 2.68 Å. In the second Co site, Co(2) is bonded in a 8-coordinate geometry to two equivalent Nb(1), two equivalent Nb(2), two equivalent Sn(1), and two equivalent Sn(2) atoms. There is one shorter (2.62 Å) and one longer (2.74 Å) Co(2)-Sn(1) bond length. Both Co(2)-Sn(2) bond lengths are 2.68 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent Nb(1), two equivalent Nb(2), four equivalent Co(1), and four equivalent Co(2) atoms to form distorted SnNb4Co8 cuboctahedra that share corners with four equivalent Sn(1)Nb4Co8 cuboctahedra, edges with four equivalent Sn(1)Nb4Co8 cuboctahedra, edges with four equivalent Sn(2)Nb4Co8 cuboctahedra, faces with four equivalent Nb(1)Co8Sn4 cuboctahedra, and faces with four equivalent Sn(2)Nb4Co8 cuboctahedra. In the second Sn site, Sn(2) is bonded to two equivalent Nb(1), two equivalent Nb(2), four equivalent Co(1), and four equivalent Co(2) atoms to form distorted SnNb4Co8 cuboctahedra that share corners with two equivalent Sn(2)Nb4Co8 cuboctahedra, corners with eight equivalent Nb(1)Co8Sn4 cuboctahedra, edges with two equivalent Sn(2)Nb4Co8 cuboctahedra, edges with four equivalent Sn(1)Nb4Co8 cuboctahedra, faces with two equivalent Nb(1)Co8Sn4 cuboctahedra, faces with two equivalent Sn(2)Nb4Co8 cuboctahedra, and faces with four equivalent Sn(1)Nb4Co8 cuboctahedra.