Na2Pr4O2Cl9 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded to one Cl(2), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms to form a mixture of distorted edge and corner-sharing NaCl6 pentagonal pyramids. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), one Cl(5), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. In the second Pr site, Pr(2) is bonded in a 2-coordinate geometry to two equivalent O(1), one Cl(1), one Cl(3), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to two equivalent O(1), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms. O(1) is bonded to one Pr(1), one Pr(3), and two equivalent Pr(2) atoms to form edge-sharing OPr4 tetrahedra. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a see-saw-like geometry to two equivalent Na(1), one Pr(2), and one Pr(3) atom. In the second Cl site, Cl(2) is bonded in a distorted see-saw-like geometry to one Na(1), one Pr(1), and two equivalent Pr(2) atoms. In the third Cl site, Cl(3) is bonded in a distorted T-shaped geometry to one Pr(3) and two equivalent Pr(2) atoms. In the fourth Cl site, Cl(4) is bonded in a 6-coordinate geometry to two equivalent Na(1), one Pr(1), one Pr(3), and two equivalent Pr(2) atoms. In the fifth Cl site, Cl(5) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Pr(1), and one Pr(3) atom. In the sixth Cl site, Cl(6) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Pr(2) atoms.
Na2Pr4O2Cl9 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded to one Cl(2), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms to form a mixture of distorted edge and corner-sharing NaCl6 pentagonal pyramids. The Na(1)-Cl(2) bond length is 2.93 Å. The Na(1)-Cl(5) bond length is 2.83 Å. There is one shorter (2.86 Å) and one longer (2.96 Å) Na(1)-Cl(1) bond length. There is one shorter (2.85 Å) and one longer (2.89 Å) Na(1)-Cl(4) bond length. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), one Cl(5), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. Both Pr(1)-O(1) bond lengths are 2.41 Å. The Pr(1)-Cl(5) bond length is 2.96 Å. The Pr(1)-Cl(6) bond length is 2.94 Å. Both Pr(1)-Cl(2) bond lengths are 2.90 Å. Both Pr(1)-Cl(4) bond lengths are 3.15 Å. In the second Pr site, Pr(2) is bonded in a 2-coordinate geometry to two equivalent O(1), one Cl(1), one Cl(3), one Cl(6), two equivalent Cl(2), and two equivalent Cl(4) atoms. There is one shorter (2.33 Å) and one longer (2.34 Å) Pr(2)-O(1) bond length. The Pr(2)-Cl(1) bond length is 2.92 Å. The Pr(2)-Cl(3) bond length is 2.96 Å. The Pr(2)-Cl(6) bond length is 2.97 Å. There is one shorter (2.93 Å) and one longer (3.12 Å) Pr(2)-Cl(2) bond length. There is one shorter (3.29 Å) and one longer (3.42 Å) Pr(2)-Cl(4) bond length. In the third Pr site, Pr(3) is bonded in a 8-coordinate geometry to two equivalent O(1), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms. Both Pr(3)-O(1) bond lengths are 2.39 Å. The Pr(3)-Cl(3) bond length is 2.93 Å. The Pr(3)-Cl(5) bond length is 2.92 Å. Both Pr(3)-Cl(1) bond lengths are 2.92 Å. Both Pr(3)-Cl(4) bond lengths are 3.27 Å. O(1) is bonded to one Pr(1), one Pr(3), and two equivalent Pr(2) atoms to form edge-sharing OPr4 tetrahedra. There are six inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a see-saw-like geometry to two equivalent Na(1), one Pr(2), and one Pr(3) atom. In the second Cl site, Cl(2) is bonded in a distorted see-saw-like geometry to one Na(1), one Pr(1), and two equivalent Pr(2) atoms. In the third Cl site, Cl(3) is bonded in a distorted T-shaped geometry to one Pr(3) and two equivalent Pr(2) atoms. In the fourth Cl site, Cl(4) is bonded in a 6-coordinate geometry to two equivalent Na(1), one Pr(1), one Pr(3), and two equivalent Pr(2) atoms. In the fifth Cl site, Cl(5) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Pr(1), and one Pr(3) atom. In the sixth Cl site, Cl(6) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Pr(2) atoms.