LiCsBaP2O7 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(7) atoms. Li(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. Ba(1) is bonded in a 8-coordinate geometry to one O(4), one O(5), one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Li(1)O4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Li(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cs(1), one Li(1), one Ba(1), and one P(2) atom. In the second O site, O(5) is bonded in a 2-coordinate geometry to one Li(1), one Ba(1), and one P(1) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to one Li(1), one Ba(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Cs(1), one Ba(1), and one P(2) atom. In the fifth O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Cs(1), one P(1), and one P(2) atom. In the sixth O site, O(2) is bonded in a 2-coordinate geometry to one Li(1), two equivalent Ba(1), and one P(1) atom. In the seventh O site, O(3) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Ba(1), and one P(1) atom.
LiCsBaP2O7 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 6-coordinate geometry to one O(3), one O(4), two equivalent O(1), and two equivalent O(7) atoms. The Cs(1)-O(3) bond length is 3.27 Å. The Cs(1)-O(4) bond length is 3.30 Å. There is one shorter (3.26 Å) and one longer (3.31 Å) Cs(1)-O(1) bond length. There is one shorter (3.06 Å) and one longer (3.29 Å) Cs(1)-O(7) bond length. Li(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra and corners with two equivalent P(2)O4 tetrahedra. The Li(1)-O(2) bond length is 2.13 Å. The Li(1)-O(4) bond length is 2.00 Å. The Li(1)-O(5) bond length is 1.94 Å. The Li(1)-O(6) bond length is 1.93 Å. Ba(1) is bonded in a 8-coordinate geometry to one O(4), one O(5), one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms. The Ba(1)-O(4) bond length is 2.94 Å. The Ba(1)-O(5) bond length is 2.81 Å. The Ba(1)-O(6) bond length is 2.74 Å. The Ba(1)-O(7) bond length is 2.66 Å. Both Ba(1)-O(2) bond lengths are 2.93 Å. There is one shorter (2.73 Å) and one longer (2.87 Å) Ba(1)-O(3) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Li(1)O4 tetrahedra. The P(1)-O(1) bond length is 1.64 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Li(1)O4 tetrahedra. The P(2)-O(1) bond length is 1.67 Å. The P(2)-O(4) bond length is 1.54 Å. The P(2)-O(6) bond length is 1.53 Å. The P(2)-O(7) bond length is 1.52 Å. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Cs(1), one Li(1), one Ba(1), and one P(2) atom. In the second O site, O(5) is bonded in a 2-coordinate geometry to one Li(1), one Ba(1), and one P(1) atom. In the third O site, O(6) is bonded in a 2-coordinate geometry to one Li(1), one Ba(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Cs(1), one Ba(1), and one P(2) atom. In the fifth O site, O(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Cs(1), one P(1), and one P(2) atom. In the sixth O site, O(2) is bonded in a 2-coordinate geometry to one Li(1), two equivalent Ba(1), and one P(1) atom. In the seventh O site, O(3) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Ba(1), and one P(1) atom.