Ba3LaCl9 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one Cl(3), one Cl(6), two equivalent Cl(2), and four equivalent Cl(5) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one Cl(4), two equivalent Cl(5), two equivalent Cl(6), and four equivalent Cl(1) atoms. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to one Cl(4), two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(5) atoms. La(1) is bonded in an octahedral geometry to one Cl(3), one Cl(6), two equivalent Cl(1), and two equivalent Cl(2) atoms. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one Ba(3), two equivalent Ba(2), and one La(1) atom to form distorted ClBa3La tetrahedra that share corners with two equivalent Cl(1)Ba3La tetrahedra, corners with four equivalent Cl(5)Ba4 tetrahedra,  an edgeedge with one Cl(5)Ba4 tetrahedra, and edges with three equivalent Cl(1)Ba3La tetrahedra. In the second Cl site, Cl(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(3), and one La(1) atom. In the third Cl site, Cl(3) is bonded in an L-shaped geometry to one Ba(1) and one La(1) atom. In the fourth Cl site, Cl(4) is bonded in a bent 120 degrees geometry to one Ba(2) and one Ba(3) atom. In the fifth Cl site, Cl(5) is bonded to one Ba(2), one Ba(3), and two equivalent Ba(1) atoms to form ClBa4 tetrahedra that share corners with two equivalent Cl(5)Ba4 tetrahedra, corners with four equivalent Cl(1)Ba3La tetrahedra,  an edgeedge with one Cl(1)Ba3La tetrahedra, and edges with three equivalent Cl(5)Ba4 tetrahedra. In the sixth Cl site, Cl(6) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Ba(2), and one La(1) atom.
Ba3LaCl9 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one Cl(3), one Cl(6), two equivalent Cl(2), and four equivalent Cl(5) atoms. The Ba(1)-Cl(3) bond length is 3.25 Å. The Ba(1)-Cl(6) bond length is 3.18 Å. Both Ba(1)-Cl(2) bond lengths are 3.50 Å. There are two shorter (3.15 Å) and two longer (3.28 Å) Ba(1)-Cl(5) bond lengths. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one Cl(4), two equivalent Cl(5), two equivalent Cl(6), and four equivalent Cl(1) atoms. The Ba(2)-Cl(4) bond length is 2.98 Å. Both Ba(2)-Cl(5) bond lengths are 3.10 Å. Both Ba(2)-Cl(6) bond lengths are 3.79 Å. There are two shorter (3.25 Å) and two longer (3.76 Å) Ba(2)-Cl(1) bond lengths. In the third Ba site, Ba(3) is bonded in a 7-coordinate geometry to one Cl(4), two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(5) atoms. The Ba(3)-Cl(4) bond length is 3.13 Å. Both Ba(3)-Cl(1) bond lengths are 3.22 Å. Both Ba(3)-Cl(2) bond lengths are 3.08 Å. Both Ba(3)-Cl(5) bond lengths are 3.50 Å. La(1) is bonded in an octahedral geometry to one Cl(3), one Cl(6), two equivalent Cl(1), and two equivalent Cl(2) atoms. The La(1)-Cl(3) bond length is 2.76 Å. The La(1)-Cl(6) bond length is 2.75 Å. Both La(1)-Cl(1) bond lengths are 2.83 Å. Both La(1)-Cl(2) bond lengths are 2.70 Å. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to one Ba(3), two equivalent Ba(2), and one La(1) atom to form distorted ClBa3La tetrahedra that share corners with two equivalent Cl(1)Ba3La tetrahedra, corners with four equivalent Cl(5)Ba4 tetrahedra,  an edgeedge with one Cl(5)Ba4 tetrahedra, and edges with three equivalent Cl(1)Ba3La tetrahedra. In the second Cl site, Cl(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ba(3), and one La(1) atom. In the third Cl site, Cl(3) is bonded in an L-shaped geometry to one Ba(1) and one La(1) atom. In the fourth Cl site, Cl(4) is bonded in a bent 120 degrees geometry to one Ba(2) and one Ba(3) atom. In the fifth Cl site, Cl(5) is bonded to one Ba(2), one Ba(3), and two equivalent Ba(1) atoms to form ClBa4 tetrahedra that share corners with two equivalent Cl(5)Ba4 tetrahedra, corners with four equivalent Cl(1)Ba3La tetrahedra,  an edgeedge with one Cl(1)Ba3La tetrahedra, and edges with three equivalent Cl(5)Ba4 tetrahedra. In the sixth Cl site, Cl(6) is bonded in a 2-coordinate geometry to one Ba(1), two equivalent Ba(2), and one La(1) atom.