Tm3Pt2Ga9 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Ga(3) and eight equivalent Ga(2) atoms to form distorted TmGa12 cuboctahedra that share edges with two equivalent Ga(1)Tm4Ga4Pt4 cuboctahedra and faces with two equivalent Tm(1)Ga12 cuboctahedra. In the second Tm site, Tm(2) is bonded in a 12-coordinate geometry to two equivalent Pt(1), two equivalent Ga(1), four equivalent Ga(2), and six equivalent Ga(3) atoms. Pt(1) is bonded in a 10-coordinate geometry to two equivalent Tm(2), two equivalent Ga(1), two equivalent Ga(2), and four equivalent Ga(3) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to four equivalent Tm(2), four equivalent Pt(1), and four equivalent Ga(3) atoms to form GaTm4Ga4Pt4 cuboctahedra that share edges with two equivalent Tm(1)Ga12 cuboctahedra and faces with two equivalent Ga(1)Tm4Ga4Pt4 cuboctahedra. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), two equivalent Tm(2), one Pt(1), one Ga(2), and three equivalent Ga(3) atoms. In the third Ga site, Ga(3) is bonded in a 10-coordinate geometry to one Tm(1), three equivalent Tm(2), two equivalent Pt(1), one Ga(1), and three equivalent Ga(2) atoms.
Tm3Pt2Ga9 crystallizes in the orthorhombic Immm space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Ga(3) and eight equivalent Ga(2) atoms to form distorted TmGa12 cuboctahedra that share edges with two equivalent Ga(1)Tm4Ga4Pt4 cuboctahedra and faces with two equivalent Tm(1)Ga12 cuboctahedra. All Tm(1)-Ga(3) bond lengths are 3.26 Å. All Tm(1)-Ga(2) bond lengths are 3.12 Å. In the second Tm site, Tm(2) is bonded in a 12-coordinate geometry to two equivalent Pt(1), two equivalent Ga(1), four equivalent Ga(2), and six equivalent Ga(3) atoms. Both Tm(2)-Pt(1) bond lengths are 3.04 Å. Both Tm(2)-Ga(1) bond lengths are 3.14 Å. All Tm(2)-Ga(2) bond lengths are 3.09 Å. There are four shorter (3.08 Å) and two longer (3.50 Å) Tm(2)-Ga(3) bond lengths. Pt(1) is bonded in a 10-coordinate geometry to two equivalent Tm(2), two equivalent Ga(1), two equivalent Ga(2), and four equivalent Ga(3) atoms. Both Pt(1)-Ga(1) bond lengths are 2.87 Å. Both Pt(1)-Ga(2) bond lengths are 2.58 Å. All Pt(1)-Ga(3) bond lengths are 2.70 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to four equivalent Tm(2), four equivalent Pt(1), and four equivalent Ga(3) atoms to form GaTm4Ga4Pt4 cuboctahedra that share edges with two equivalent Tm(1)Ga12 cuboctahedra and faces with two equivalent Ga(1)Tm4Ga4Pt4 cuboctahedra. All Ga(1)-Ga(3) bond lengths are 2.72 Å. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Tm(1), two equivalent Tm(2), one Pt(1), one Ga(2), and three equivalent Ga(3) atoms. The Ga(2)-Ga(2) bond length is 2.55 Å. There are two shorter (2.61 Å) and one longer (2.66 Å) Ga(2)-Ga(3) bond length. In the third Ga site, Ga(3) is bonded in a 10-coordinate geometry to one Tm(1), three equivalent Tm(2), two equivalent Pt(1), one Ga(1), and three equivalent Ga(2) atoms.