GaPt2 crystallizes in the orthorhombic Pmma space group. There are five inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to four equivalent Pt(3), two equivalent Ga(1), and four equivalent Ga(3) atoms to form distorted PtGa6Pt4 cuboctahedra that share corners with two equivalent Pt(1)Ga6Pt4 cuboctahedra, corners with four equivalent Ga(2)Pt12 cuboctahedra, and faces with two equivalent Pt(1)Ga6Pt4 cuboctahedra. In the second Pt site, Pt(2) is bonded in a 12-coordinate geometry to four equivalent Pt(4), four equivalent Pt(5), two equivalent Ga(2), and two equivalent Ga(3) atoms. In the third Pt site, Pt(3) is bonded in a 12-coordinate geometry to two equivalent Pt(1), two equivalent Pt(4), two equivalent Pt(5), one Ga(2), two equivalent Ga(1), and three equivalent Ga(3) atoms. In the fourth Pt site, Pt(4) is bonded in a 5-coordinate geometry to two equivalent Pt(2), two equivalent Pt(3), one Ga(1), two equivalent Ga(2), and two equivalent Ga(3) atoms. In the fifth Pt site, Pt(5) is bonded in a distorted square co-planar geometry to two equivalent Pt(2), two equivalent Pt(3), two equivalent Ga(2), and two equivalent Ga(3) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted body-centered cubic geometry to two equivalent Pt(1), two equivalent Pt(4), and four equivalent Pt(3) atoms. In the second Ga site, Ga(2) is bonded to two equivalent Pt(2), two equivalent Pt(3), four equivalent Pt(4), and four equivalent Pt(5) atoms to form GaPt12 cuboctahedra that share corners with two equivalent Ga(2)Pt12 cuboctahedra, corners with four equivalent Pt(1)Ga6Pt4 cuboctahedra, and faces with two equivalent Ga(2)Pt12 cuboctahedra. In the third Ga site, Ga(3) is bonded in a 10-coordinate geometry to one Pt(2), two equivalent Pt(1), two equivalent Pt(4), two equivalent Pt(5), and three equivalent Pt(3) atoms.
GaPt2 crystallizes in the orthorhombic Pmma space group. There are five inequivalent Pt sites. In the first Pt site, Pt(1) is bonded to four equivalent Pt(3), two equivalent Ga(1), and four equivalent Ga(3) atoms to form distorted PtGa6Pt4 cuboctahedra that share corners with two equivalent Pt(1)Ga6Pt4 cuboctahedra, corners with four equivalent Ga(2)Pt12 cuboctahedra, and faces with two equivalent Pt(1)Ga6Pt4 cuboctahedra. All Pt(1)-Pt(3) bond lengths are 2.79 Å. Both Pt(1)-Ga(1) bond lengths are 2.76 Å. All Pt(1)-Ga(3) bond lengths are 2.70 Å. In the second Pt site, Pt(2) is bonded in a 12-coordinate geometry to four equivalent Pt(4), four equivalent Pt(5), two equivalent Ga(2), and two equivalent Ga(3) atoms. All Pt(2)-Pt(4) bond lengths are 2.77 Å. All Pt(2)-Pt(5) bond lengths are 2.89 Å. There is one shorter (2.60 Å) and one longer (2.92 Å) Pt(2)-Ga(2) bond length. Both Pt(2)-Ga(3) bond lengths are 2.61 Å. In the third Pt site, Pt(3) is bonded in a 12-coordinate geometry to two equivalent Pt(1), two equivalent Pt(4), two equivalent Pt(5), one Ga(2), two equivalent Ga(1), and three equivalent Ga(3) atoms. Both Pt(3)-Pt(4) bond lengths are 2.81 Å. Both Pt(3)-Pt(5) bond lengths are 2.88 Å. The Pt(3)-Ga(2) bond length is 3.00 Å. Both Pt(3)-Ga(1) bond lengths are 2.54 Å. There are a spread of Pt(3)-Ga(3) bond distances ranging from 2.68-2.91 Å. In the fourth Pt site, Pt(4) is bonded in a 5-coordinate geometry to two equivalent Pt(2), two equivalent Pt(3), one Ga(1), two equivalent Ga(2), and two equivalent Ga(3) atoms. The Pt(4)-Ga(1) bond length is 2.58 Å. Both Pt(4)-Ga(2) bond lengths are 2.89 Å. Both Pt(4)-Ga(3) bond lengths are 2.65 Å. In the fifth Pt site, Pt(5) is bonded in a distorted square co-planar geometry to two equivalent Pt(2), two equivalent Pt(3), two equivalent Ga(2), and two equivalent Ga(3) atoms. Both Pt(5)-Ga(2) bond lengths are 2.71 Å. Both Pt(5)-Ga(3) bond lengths are 2.68 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a distorted body-centered cubic geometry to two equivalent Pt(1), two equivalent Pt(4), and four equivalent Pt(3) atoms. In the second Ga site, Ga(2) is bonded to two equivalent Pt(2), two equivalent Pt(3), four equivalent Pt(4), and four equivalent Pt(5) atoms to form GaPt12 cuboctahedra that share corners with two equivalent Ga(2)Pt12 cuboctahedra, corners with four equivalent Pt(1)Ga6Pt4 cuboctahedra, and faces with two equivalent Ga(2)Pt12 cuboctahedra. In the third Ga site, Ga(3) is bonded in a 10-coordinate geometry to one Pt(2), two equivalent Pt(1), two equivalent Pt(4), two equivalent Pt(5), and three equivalent Pt(3) atoms.