PrNb4O12 crystallizes in the orthorhombic Amm2 space group. Pr(1) is bonded in a 12-coordinate geometry to two equivalent O(3), two equivalent O(4), four equivalent O(1), and four equivalent O(5) atoms. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 6-28°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Pr(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Pr(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Nb(1) atoms.
PrNb4O12 crystallizes in the orthorhombic Amm2 space group. Pr(1) is bonded in a 12-coordinate geometry to two equivalent O(3), two equivalent O(4), four equivalent O(1), and four equivalent O(5) atoms. Both Pr(1)-O(3) bond lengths are 2.84 Å. Both Pr(1)-O(4) bond lengths are 2.52 Å. There are two shorter (2.51 Å) and two longer (3.09 Å) Pr(1)-O(1) bond lengths. All Pr(1)-O(5) bond lengths are 2.63 Å. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 6-28°. The Nb(1)-O(1) bond length is 2.09 Å. The Nb(1)-O(2) bond length is 1.94 Å. The Nb(1)-O(3) bond length is 1.99 Å. The Nb(1)-O(4) bond length is 2.01 Å. There is one shorter (1.99 Å) and one longer (2.02 Å) Nb(1)-O(5) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Pr(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a linear geometry to two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Pr(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Pr(1) and two equivalent Nb(1) atoms.