DOE OSTI2020
Nb5Ga13 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are three inequivalent Nb sites. In the first Nb site, Nb is bonded to twelve Ga atoms to form NbGa12 cuboctahedra that share corners with four equivalent NbGa12 cuboctahedra, edges with four equivalent NbGa12 cuboctahedra, edges with eight GaNb4Ga8 cuboctahedra, faces with four equivalent NbGa12 cuboctahedra, and faces with four GaNb4Ga8 cuboctahedra. There are a spread of Nb–Ga bond distances ranging from 2.69–3.00 Å. In the second Nb site, Nb is bonded in a 10-coordinate geometry to ten Ga atoms. There are a spread of Nb–Ga bond distances ranging from 2.73–2.96 Å. In the third Nb site, Nb is bonded to twelve Ga atoms to form NbGa12 cuboctahedra that share corners with four equivalent NbGa12 cuboctahedra, edges with eight equivalent NbGa12 cuboctahedra, edges with sixteen GaNb4Ga8 cuboctahedra, faces with four equivalent NbGa12 cuboctahedra, and faces with eight GaNb4Ga8 cuboctahedra. There are four shorter (2.69 Å) and eight longer (2.93 Å) Nb–Ga bond lengths. There are seven inequivalent Ga sites. In the first Ga site, Ga is bonded to four Nb and eight Ga atoms to form distorted GaNb4Ga8 cuboctahedra that share corners with eight equivalent GaNb4Ga8 cuboctahedra, edges with four equivalent GaNb4Ga8 cuboctahedra, edges with eight NbGa12 cuboctahedra, faces with four NbGa12 cuboctahedra, and faces with nine GaNb4Ga8 cuboctahedra. There are a spread of Ga–Ga bond distances ranging from 2.69–3.00 Å. In the second Ga site, Ga is bonded in a 10-coordinate geometry to four Nb and six Ga atoms. There are four shorter (2.69 Å) and two longer (2.86 Å) Ga–Ga bond lengths. In the third Ga site, Ga is bonded in a 8-coordinate geometry to six equivalent Nb and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.61 Å. In the fourth Ga site, Ga is bonded in a distorted square co-planar geometry to four equivalent Nb and eight Ga atoms. All Ga–Ga bond lengths are 2.93 Å. In the fifth Ga site, Ga is bonded to four Nb and eight Ga atoms to form distorted GaNb4Ga8 cuboctahedra that share corners with eight equivalent GaNb4Ga8 cuboctahedra, edges with four equivalent GaNb4Ga8 cuboctahedra, edges with eight NbGa12 cuboctahedra, faces with four NbGa12 cuboctahedra, and faces with nine GaNb4Ga8 cuboctahedra. Both Ga–Ga bond lengths are 3.01 Å. In the sixth Ga site, Ga is bonded in a 10-coordinate geometry to four Nb and six Ga atoms. Both Ga–Ga bond lengths are 2.88 Å. In the seventh Ga site, Ga is bonded in a distorted rectangular see-saw-like geometry to four equivalent Nb and eight Ga atoms.