Sr4Pr3CeNb2(CuO5)4 crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent O(4), two equivalent O(5), four equivalent O(2), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra; corners with four equivalent Sr(3)O12 cuboctahedra;  a faceface with one Sr(4)O12 cuboctahedra; faces with four equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Nb(1)O6 octahedra; faces with two equivalent Nb(2)O6 octahedra; and faces with four equivalent Cu(1,2)O5 square pyramids. In the second Sr site, Sr(2) is bonded to two equivalent O(4), two equivalent O(5), four equivalent O(2), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra; corners with four equivalent Sr(4)O12 cuboctahedra;  a faceface with one Sr(3)O12 cuboctahedra; faces with four equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Nb(1)O6 octahedra; faces with two equivalent Nb(2)O6 octahedra; and faces with four equivalent Cu(1,2)O5 square pyramids. In the third Sr site, Sr(3) is bonded to two equivalent O(6), two equivalent O(7), four equivalent O(3), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, corners with four equivalent Sr(3)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra, faces with four equivalent Sr(4)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Cu(3)O5 square pyramids, and faces with two equivalent Cu(4)O5 square pyramids. In the fourth Sr site, Sr(4) is bonded to two equivalent O(6), two equivalent O(7), four equivalent O(3), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, corners with four equivalent Sr(4)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra, faces with four equivalent Sr(3)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Cu(3)O5 square pyramids, and faces with two equivalent Cu(4)O5 square pyramids. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Pr site, Pr(2) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. In the third Pr site, Pr(3) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. Ce(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(5), one O(6), and four equivalent O(8) atoms to form NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra;  a cornercorner with one Cu(1,2)O5 square pyramid;  a cornercorner with one Cu(3)O5 square pyramid; faces with two equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Sr(3)O12 cuboctahedra; and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Nb site, Nb(2) is bonded to one O(4), one O(7), and four equivalent O(8) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra;  a cornercorner with one Cu(1,2)O5 square pyramid;  a cornercorner with one Cu(4)O5 square pyramid; faces with two equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Sr(3)O12 cuboctahedra; and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Cu sites. In the first Cu site, Cu(1,2) is bonded to one O(4) and four equivalent O(2) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra; corners with four equivalent Cu(1,2)O5 square pyramids; faces with two equivalent Sr(1)O12 cuboctahedra; and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Cu site, Cu(3) is bonded to one O(6) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with four equivalent Cu(4)O5 square pyramids, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the third Cu site, Cu(4) is bonded to one O(7) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Cu(3)O5 square pyramids, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Pr(1), one Pr(2), one Pr(3), and one Ce(1) atom to form OCePr3 tetrahedra that share corners with six equivalent O(2)Sr2CePrCu2 octahedra, corners with six equivalent O(3)Sr2Pr2Cu2 octahedra, corners with four equivalent O(1)CePr3 tetrahedra,  an edgeedge with one O(2)Sr2CePrCu2 octahedra,  an edgeedge with one O(3)Sr2Pr2Cu2 octahedra, and edges with four equivalent O(1)CePr3 tetrahedra. The corner-sharing octahedral tilt angles range from 7-70°. In the second O site, O(2) is bonded to one Sr(1); one Sr(2); one Pr(1); one Ce(1); and two equivalent Cu(1,2) atoms to form distorted OSr2CePrCu2 octahedra that share corners with two equivalent O(2)Sr2CePrCu2 octahedra, corners with two equivalent O(4)Sr4NbCu octahedra, corners with two equivalent O(5)Sr4NbCu octahedra, corners with six equivalent O(1)CePr3 tetrahedra, edges with two equivalent O(2)Sr2CePrCu2 octahedra,  an edgeedge with one O(1)CePr3 tetrahedra,  a faceface with one O(4)Sr4NbCu octahedra,  a faceface with one O(5)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 9-54°. In the third O site, O(3) is bonded to one Sr(3), one Sr(4), one Pr(2), one Pr(3), one Cu(3), and one Cu(4) atom to form distorted OSr2Pr2Cu2 octahedra that share corners with two equivalent O(3)Sr2Pr2Cu2 octahedra, corners with two equivalent O(6)Sr4NbCu octahedra, corners with two equivalent O(7)Sr4NbCu octahedra, corners with six equivalent O(1)CePr3 tetrahedra, edges with two equivalent O(3)Sr2Pr2Cu2 octahedra,  an edgeedge with one O(1)CePr3 tetrahedra,  a faceface with one O(6)Sr4NbCu octahedra,  a faceface with one O(7)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 8-53°. In the fourth O site, O(4) is bonded to two equivalent Sr(1); two equivalent Sr(2); one Nb(2); and one Cu(1,2) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(7)Sr4NbCu octahedra, corners with four equivalent O(4)Sr4NbCu octahedra, corners with eight equivalent O(2)Sr2CePrCu2 octahedra, edges with four equivalent O(5)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the fifth O site, O(5) is bonded to two equivalent Sr(1); two equivalent Sr(2); one Nb(1); and one Cu(1,2) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(6)Sr4NbCu octahedra, corners with four equivalent O(5)Sr4NbCu octahedra, corners with eight equivalent O(2)Sr2CePrCu2 octahedra, edges with four equivalent O(4)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the sixth O site, O(6) is bonded to two equivalent Sr(3), two equivalent Sr(4), one Nb(1), and one Cu(3) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(5)Sr4NbCu octahedra, corners with four equivalent O(6)Sr4NbCu octahedra, corners with eight equivalent O(3)Sr2Pr2Cu2 octahedra, edges with four equivalent O(7)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the seventh O site, O(7) is bonded to two equivalent Sr(3), two equivalent Sr(4), one Nb(2), and one Cu(4) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(4)Sr4NbCu octahedra, corners with four equivalent O(7)Sr4NbCu octahedra, corners with eight equivalent O(3)Sr2Pr2Cu2 octahedra, edges with four equivalent O(6)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the eighth O site, O(8) is bonded in a linear geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Nb(1), and one Nb(2) atom.
Sr4Pr3CeNb2(CuO5)4 crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to two equivalent O(4), two equivalent O(5), four equivalent O(2), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra; corners with four equivalent Sr(3)O12 cuboctahedra;  a faceface with one Sr(4)O12 cuboctahedra; faces with four equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Nb(1)O6 octahedra; faces with two equivalent Nb(2)O6 octahedra; and faces with four equivalent Cu(1,2)O5 square pyramids. Both Sr(1)-O(4) bond lengths are 2.83 Å. Both Sr(1)-O(5) bond lengths are 2.83 Å. All Sr(1)-O(2) bond lengths are 2.82 Å. All Sr(1)-O(8) bond lengths are 3.08 Å. In the second Sr site, Sr(2) is bonded to two equivalent O(4), two equivalent O(5), four equivalent O(2), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra; corners with four equivalent Sr(4)O12 cuboctahedra;  a faceface with one Sr(3)O12 cuboctahedra; faces with four equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Nb(1)O6 octahedra; faces with two equivalent Nb(2)O6 octahedra; and faces with four equivalent Cu(1,2)O5 square pyramids. Both Sr(2)-O(4) bond lengths are 2.84 Å. Both Sr(2)-O(5) bond lengths are 2.84 Å. All Sr(2)-O(2) bond lengths are 2.74 Å. All Sr(2)-O(8) bond lengths are 3.12 Å. In the third Sr site, Sr(3) is bonded to two equivalent O(6), two equivalent O(7), four equivalent O(3), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, corners with four equivalent Sr(3)O12 cuboctahedra,  a faceface with one Sr(2)O12 cuboctahedra, faces with four equivalent Sr(4)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Cu(3)O5 square pyramids, and faces with two equivalent Cu(4)O5 square pyramids. Both Sr(3)-O(6) bond lengths are 2.84 Å. Both Sr(3)-O(7) bond lengths are 2.84 Å. All Sr(3)-O(3) bond lengths are 2.75 Å. All Sr(3)-O(8) bond lengths are 3.11 Å. In the fourth Sr site, Sr(4) is bonded to two equivalent O(6), two equivalent O(7), four equivalent O(3), and four equivalent O(8) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, corners with four equivalent Sr(4)O12 cuboctahedra,  a faceface with one Sr(1)O12 cuboctahedra, faces with four equivalent Sr(3)O12 cuboctahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, faces with two equivalent Cu(3)O5 square pyramids, and faces with two equivalent Cu(4)O5 square pyramids. Both Sr(4)-O(6) bond lengths are 2.84 Å. Both Sr(4)-O(7) bond lengths are 2.84 Å. All Sr(4)-O(3) bond lengths are 2.75 Å. All Sr(4)-O(8) bond lengths are 3.11 Å. There are three inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Pr(1)-O(1) bond lengths are 2.41 Å. All Pr(1)-O(2) bond lengths are 2.61 Å. In the second Pr site, Pr(2) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. All Pr(2)-O(1) bond lengths are 2.40 Å. All Pr(2)-O(3) bond lengths are 2.63 Å. In the third Pr site, Pr(3) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. All Pr(3)-O(1) bond lengths are 2.40 Å. All Pr(3)-O(3) bond lengths are 2.63 Å. Ce(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All Ce(1)-O(1) bond lengths are 2.26 Å. All Ce(1)-O(2) bond lengths are 2.63 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(5), one O(6), and four equivalent O(8) atoms to form NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra;  a cornercorner with one Cu(1,2)O5 square pyramid;  a cornercorner with one Cu(3)O5 square pyramid; faces with two equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Sr(3)O12 cuboctahedra; and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Nb(1)-O(5) bond length is 2.00 Å. The Nb(1)-O(6) bond length is 2.00 Å. All Nb(1)-O(8) bond lengths are 1.98 Å. In the second Nb site, Nb(2) is bonded to one O(4), one O(7), and four equivalent O(8) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra;  a cornercorner with one Cu(1,2)O5 square pyramid;  a cornercorner with one Cu(4)O5 square pyramid; faces with two equivalent Sr(1)O12 cuboctahedra; faces with two equivalent Sr(2)O12 cuboctahedra; faces with two equivalent Sr(3)O12 cuboctahedra; and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Nb(2)-O(4) bond length is 2.00 Å. The Nb(2)-O(7) bond length is 2.00 Å. All Nb(2)-O(8) bond lengths are 1.99 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1,2) is bonded to one O(4) and four equivalent O(2) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra; corners with four equivalent Cu(1,2)O5 square pyramids; faces with two equivalent Sr(1)O12 cuboctahedra; and faces with two equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(1,2)-O(4) bond length is 2.17 Å. All Cu(1,2)-O(2) bond lengths are 1.99 Å. In the second Cu site, Cu(3) is bonded to one O(6) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with four equivalent Cu(4)O5 square pyramids, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(3)-O(6) bond length is 2.16 Å. All Cu(3)-O(3) bond lengths are 1.99 Å. In the third Cu site, Cu(4) is bonded to one O(7) and four equivalent O(3) atoms to form CuO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Cu(3)O5 square pyramids, faces with two equivalent Sr(3)O12 cuboctahedra, and faces with two equivalent Sr(4)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Cu(4)-O(7) bond length is 2.16 Å. All Cu(4)-O(3) bond lengths are 1.99 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Pr(1), one Pr(2), one Pr(3), and one Ce(1) atom to form OCePr3 tetrahedra that share corners with six equivalent O(2)Sr2CePrCu2 octahedra, corners with six equivalent O(3)Sr2Pr2Cu2 octahedra, corners with four equivalent O(1)CePr3 tetrahedra,  an edgeedge with one O(2)Sr2CePrCu2 octahedra,  an edgeedge with one O(3)Sr2Pr2Cu2 octahedra, and edges with four equivalent O(1)CePr3 tetrahedra. The corner-sharing octahedral tilt angles range from 7-70°. In the second O site, O(2) is bonded to one Sr(1); one Sr(2); one Pr(1); one Ce(1); and two equivalent Cu(1,2) atoms to form distorted OSr2CePrCu2 octahedra that share corners with two equivalent O(2)Sr2CePrCu2 octahedra, corners with two equivalent O(4)Sr4NbCu octahedra, corners with two equivalent O(5)Sr4NbCu octahedra, corners with six equivalent O(1)CePr3 tetrahedra, edges with two equivalent O(2)Sr2CePrCu2 octahedra,  an edgeedge with one O(1)CePr3 tetrahedra,  a faceface with one O(4)Sr4NbCu octahedra,  a faceface with one O(5)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 9-54°. In the third O site, O(3) is bonded to one Sr(3), one Sr(4), one Pr(2), one Pr(3), one Cu(3), and one Cu(4) atom to form distorted OSr2Pr2Cu2 octahedra that share corners with two equivalent O(3)Sr2Pr2Cu2 octahedra, corners with two equivalent O(6)Sr4NbCu octahedra, corners with two equivalent O(7)Sr4NbCu octahedra, corners with six equivalent O(1)CePr3 tetrahedra, edges with two equivalent O(3)Sr2Pr2Cu2 octahedra,  an edgeedge with one O(1)CePr3 tetrahedra,  a faceface with one O(6)Sr4NbCu octahedra,  a faceface with one O(7)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 8-53°. In the fourth O site, O(4) is bonded to two equivalent Sr(1); two equivalent Sr(2); one Nb(2); and one Cu(1,2) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(7)Sr4NbCu octahedra, corners with four equivalent O(4)Sr4NbCu octahedra, corners with eight equivalent O(2)Sr2CePrCu2 octahedra, edges with four equivalent O(5)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. In the fifth O site, O(5) is bonded to two equivalent Sr(1); two equivalent Sr(2); one Nb(1); and one Cu(1,2) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(6)Sr4NbCu octahedra, corners with four equivalent O(5)Sr4NbCu octahedra, corners with eight equivalent O(2)Sr2CePrCu2 octahedra, edges with four equivalent O(4)Sr4NbCu octahedra, and faces with four equivalent O(2)Sr2CePrCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-54°. The O(5)-Cu(1,2) bond length is 2.17 Å. In the sixth O site, O(6) is bonded to two equivalent Sr(3), two equivalent Sr(4), one Nb(1), and one Cu(3) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(5)Sr4NbCu octahedra, corners with four equivalent O(6)Sr4NbCu octahedra, corners with eight equivalent O(3)Sr2Pr2Cu2 octahedra, edges with four equivalent O(7)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the seventh O site, O(7) is bonded to two equivalent Sr(3), two equivalent Sr(4), one Nb(2), and one Cu(4) atom to form distorted OSr4NbCu octahedra that share  a cornercorner with one O(4)Sr4NbCu octahedra, corners with four equivalent O(7)Sr4NbCu octahedra, corners with eight equivalent O(3)Sr2Pr2Cu2 octahedra, edges with four equivalent O(6)Sr4NbCu octahedra, and faces with four equivalent O(3)Sr2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-53°. In the eighth O site, O(8) is bonded in a linear geometry to one Sr(1), one Sr(2), one Sr(3), one Sr(4), one Nb(1), and one Nb(2) atom.