Ca3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Ga(3) and eight equivalent Ga(2) atoms to form a mixture of edge and face-sharing CaGa12 cuboctahedra. In the second Ca site, Ca(2) is bonded in a 14-coordinate geometry to two equivalent Ga(2), four equivalent Ga(1), four equivalent Ga(3), and four equivalent Ga(4) atoms. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to four equivalent Ca(2), four equivalent Ga(1), and four equivalent Ga(4) atoms to form a mixture of distorted corner and face-sharing GaCa4Ga8 cuboctahedra. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Ca(2), four equivalent Ca(1), one Ga(2), and two equivalent Ga(3) atoms. In the third Ga site, Ga(3) is bonded in a 9-coordinate geometry to two equivalent Ca(1), four equivalent Ca(2), one Ga(4), and two equivalent Ga(2) atoms. In the fourth Ga site, Ga(4) is bonded in a 9-coordinate geometry to four equivalent Ca(2), one Ga(3), and four equivalent Ga(1) atoms.
Ca3Ga8 crystallizes in the orthorhombic Immm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to four equivalent Ga(3) and eight equivalent Ga(2) atoms to form a mixture of edge and face-sharing CaGa12 cuboctahedra. All Ca(1)-Ga(3) bond lengths are 3.23 Å. All Ca(1)-Ga(2) bond lengths are 3.27 Å. In the second Ca site, Ca(2) is bonded in a 14-coordinate geometry to two equivalent Ga(2), four equivalent Ga(1), four equivalent Ga(3), and four equivalent Ga(4) atoms. Both Ca(2)-Ga(2) bond lengths are 3.29 Å. There are two shorter (3.41 Å) and two longer (3.42 Å) Ca(2)-Ga(1) bond lengths. All Ca(2)-Ga(3) bond lengths are 3.30 Å. All Ca(2)-Ga(4) bond lengths are 3.24 Å. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to four equivalent Ca(2), four equivalent Ga(1), and four equivalent Ga(4) atoms to form a mixture of distorted corner and face-sharing GaCa4Ga8 cuboctahedra. All Ga(1)-Ga(1) bond lengths are 3.03 Å. There are two shorter (2.61 Å) and two longer (2.63 Å) Ga(1)-Ga(4) bond lengths. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to two equivalent Ca(2), four equivalent Ca(1), one Ga(2), and two equivalent Ga(3) atoms. The Ga(2)-Ga(2) bond length is 2.46 Å. Both Ga(2)-Ga(3) bond lengths are 2.44 Å. In the third Ga site, Ga(3) is bonded in a 9-coordinate geometry to two equivalent Ca(1), four equivalent Ca(2), one Ga(4), and two equivalent Ga(2) atoms. The Ga(3)-Ga(4) bond length is 2.46 Å. In the fourth Ga site, Ga(4) is bonded in a 9-coordinate geometry to four equivalent Ca(2), one Ga(3), and four equivalent Ga(1) atoms.