Pr(NiO3)2 crystallizes in the triclinic P1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(4), one O(5), one O(7), and two equivalent O(12) atoms. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(4), one O(5), one O(8), one O(9), and two equivalent O(6) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(5), and one O(8) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 12-22°. In the second Ni site, Ni(2) is bonded to one O(1), one O(11), one O(12), one O(3), one O(4), and one O(9) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 14-22°. In the third Ni site, Ni(3) is bonded to one O(11), one O(3), one O(4), one O(6), one O(7), and one O(9) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 13-21°. In the fourth Ni site, Ni(4) is bonded to one O(10), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 12-21°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(1), and one Ni(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(2), and one Ni(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(2), and one Ni(3) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(1), and one Ni(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Pr(2), one Ni(3), and one Ni(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(3), and one Ni(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(1), and one Ni(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(2), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Pr(1), one Pr(2), one Ni(1), and one Ni(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(2), and one Ni(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Pr(1), one Ni(1), and one Ni(2) atom.
Pr(NiO3)2 crystallizes in the triclinic P1 space group. There are two inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(4), one O(5), one O(7), and two equivalent O(12) atoms. The Pr(1)-O(10) bond length is 2.70 Å. The Pr(1)-O(11) bond length is 2.74 Å. The Pr(1)-O(2) bond length is 2.44 Å. The Pr(1)-O(3) bond length is 2.46 Å. The Pr(1)-O(4) bond length is 2.54 Å. The Pr(1)-O(5) bond length is 2.55 Å. The Pr(1)-O(7) bond length is 2.41 Å. There is one shorter (2.60 Å) and one longer (2.73 Å) Pr(1)-O(12) bond length. In the second Pr site, Pr(2) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(4), one O(5), one O(8), one O(9), and two equivalent O(6) atoms. The Pr(2)-O(1) bond length is 2.40 Å. The Pr(2)-O(10) bond length is 2.56 Å. The Pr(2)-O(11) bond length is 2.52 Å. The Pr(2)-O(4) bond length is 2.76 Å. The Pr(2)-O(5) bond length is 2.74 Å. The Pr(2)-O(8) bond length is 2.43 Å. The Pr(2)-O(9) bond length is 2.46 Å. There is one shorter (2.59 Å) and one longer (2.74 Å) Pr(2)-O(6) bond length. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(5), and one O(8) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 12-22°. The Ni(1)-O(1) bond length is 1.84 Å. The Ni(1)-O(10) bond length is 1.87 Å. The Ni(1)-O(12) bond length is 1.86 Å. The Ni(1)-O(2) bond length is 1.83 Å. The Ni(1)-O(5) bond length is 1.86 Å. The Ni(1)-O(8) bond length is 1.84 Å. In the second Ni site, Ni(2) is bonded to one O(1), one O(11), one O(12), one O(3), one O(4), and one O(9) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 14-22°. The Ni(2)-O(1) bond length is 1.97 Å. The Ni(2)-O(11) bond length is 2.02 Å. The Ni(2)-O(12) bond length is 2.04 Å. The Ni(2)-O(3) bond length is 1.97 Å. The Ni(2)-O(4) bond length is 2.00 Å. The Ni(2)-O(9) bond length is 1.98 Å. In the third Ni site, Ni(3) is bonded to one O(11), one O(3), one O(4), one O(6), one O(7), and one O(9) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 13-21°. The Ni(3)-O(11) bond length is 1.86 Å. The Ni(3)-O(3) bond length is 1.84 Å. The Ni(3)-O(4) bond length is 1.86 Å. The Ni(3)-O(6) bond length is 1.87 Å. The Ni(3)-O(7) bond length is 1.83 Å. The Ni(3)-O(9) bond length is 1.85 Å. In the fourth Ni site, Ni(4) is bonded to one O(10), one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 12-21°. The Ni(4)-O(10) bond length is 2.03 Å. The Ni(4)-O(2) bond length is 1.97 Å. The Ni(4)-O(5) bond length is 2.04 Å. The Ni(4)-O(6) bond length is 2.03 Å. The Ni(4)-O(7) bond length is 1.96 Å. The Ni(4)-O(8) bond length is 1.97 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(1), and one Ni(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(2), and one Ni(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(2), and one Ni(3) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(1), and one Ni(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Pr(2), one Ni(3), and one Ni(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Ni(3), and one Ni(4) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(1), and one Ni(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Pr(2), one Ni(2), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Pr(1), one Pr(2), one Ni(1), and one Ni(4) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Pr(1), one Pr(2), one Ni(2), and one Ni(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent Pr(1), one Ni(1), and one Ni(2) atom.