Nd2Ce8O19 is alpha bismuth trifluoride-derived structured and crystallizes in the triclinic P1 space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to two equivalent O(10), two equivalent O(11), and two equivalent O(8) atoms. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to two equivalent O(11), two equivalent O(12), and two equivalent O(13) atoms. There are eight inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(12), two equivalent O(13), two equivalent O(14), and two equivalent O(15) atoms. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(16), two equivalent O(17), and two equivalent O(2) atoms. In the third Ce site, Ce(3) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(14), two equivalent O(15), and two equivalent O(16) atoms. In the fourth Ce site, Ce(4) is bonded in a body-centered cubic geometry to two equivalent O(17), two equivalent O(18), two equivalent O(2), and two equivalent O(3) atoms. In the fifth Ce site, Ce(5) is bonded in a body-centered cubic geometry to two equivalent O(18), two equivalent O(19), two equivalent O(3), and two equivalent O(4) atoms. In the sixth Ce site, Ce(6) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(9) atoms. In the seventh Ce site, Ce(7) is bonded in a body-centered cubic geometry to two equivalent O(19), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. In the eighth Ce site, Ce(8) is bonded in a body-centered cubic geometry to two equivalent O(10), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ce(2) and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Ce(2) and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(4) and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Ce(5) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(6) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Ce(6) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Ce(6) and two equivalent Ce(8) atoms to form OCe4 tetrahedra that share corners with two equivalent O(10)Ce2Nd2 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(10)Ce2Nd2 tetrahedra,  an edgeedge with one O(6)Ce4 tetrahedra, and edges with four equivalent O(9)Ce4 tetrahedra. In the eighth O site, O(8) is bonded to two equivalent Nd(1) and two equivalent Ce(8) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(9)Ce4 tetrahedra, corners with two equivalent O(11)Nd4 tetrahedra, corners with four equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(9)Ce4 tetrahedra,  an edgeedge with one O(11)Nd4 tetrahedra, and edges with four equivalent O(10)Ce2Nd2 tetrahedra. In the ninth O site, O(9) is bonded to two equivalent Ce(6) and two equivalent Ce(8) atoms to form OCe4 tetrahedra that share corners with two equivalent O(8)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(9)Ce4 tetrahedra,  an edgeedge with one O(8)Ce2Nd2 tetrahedra,  an edgeedge with one O(5)Ce4 tetrahedra, and edges with four equivalent O(7)Ce4 tetrahedra. In the tenth O site, O(10) is bonded to two equivalent Nd(1) and two equivalent Ce(8) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(7)Ce4 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(9)Ce4 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(7)Ce4 tetrahedra, and edges with four equivalent O(8)Ce2Nd2 tetrahedra. In the eleventh O site, O(11) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(12)Ce2Nd2 tetrahedra, corners with two equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(12)Ce2Nd2 tetrahedra, and  an edgeedge with one O(8)Ce2Nd2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Nd(2) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(15)Ce4 tetrahedra, corners with two equivalent O(11)Nd4 tetrahedra, corners with four equivalent O(12)Ce2Nd2 tetrahedra, corners with four equivalent O(14)Ce4 tetrahedra,  an edgeedge with one O(15)Ce4 tetrahedra,  an edgeedge with one O(11)Nd4 tetrahedra, and edges with four equivalent O(13)Ce2Nd2 tetrahedra. In the thirteenth O site, O(13) is bonded to two equivalent Nd(2) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(14)Ce4 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(15)Ce4 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(14)Ce4 tetrahedra, and edges with four equivalent O(12)Ce2Nd2 tetrahedra. In the fourteenth O site, O(14) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(13)Ce2Nd2 tetrahedra, corners with two equivalent O(16)Ce4 tetrahedra, corners with four equivalent O(12)Ce2Nd2 tetrahedra, corners with four equivalent O(1)Ce4 tetrahedra, corners with four equivalent O(14)Ce4 tetrahedra,  an edgeedge with one O(13)Ce2Nd2 tetrahedra,  an edgeedge with one O(16)Ce4 tetrahedra, and edges with four equivalent O(15)Ce4 tetrahedra. In the fifteenth O site, O(15) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(12)Ce2Nd2 tetrahedra, corners with two equivalent O(1)Ce4 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(15)Ce4 tetrahedra, corners with four equivalent O(16)Ce4 tetrahedra,  an edgeedge with one O(12)Ce2Nd2 tetrahedra,  an edgeedge with one O(1)Ce4 tetrahedra, and edges with four equivalent O(14)Ce4 tetrahedra. In the sixteenth O site, O(16) is bonded to two equivalent Ce(2) and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventeenth O site, O(17) is bonded to two equivalent Ce(2) and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the eighteenth O site, O(18) is bonded to two equivalent Ce(4) and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the nineteenth O site, O(19) is bonded to two equivalent Ce(5) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra.
Nd2Ce8O19 is alpha bismuth trifluoride-derived structured and crystallizes in the triclinic P1 space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 6-coordinate geometry to two equivalent O(10), two equivalent O(11), and two equivalent O(8) atoms. There is one shorter (2.24 Å) and one longer (2.25 Å) Nd(1)-O(10) bond length. There is one shorter (2.49 Å) and one longer (2.50 Å) Nd(1)-O(11) bond length. Both Nd(1)-O(8) bond lengths are 2.39 Å. In the second Nd site, Nd(2) is bonded in a 6-coordinate geometry to two equivalent O(11), two equivalent O(12), and two equivalent O(13) atoms. There is one shorter (2.49 Å) and one longer (2.50 Å) Nd(2)-O(11) bond length. Both Nd(2)-O(12) bond lengths are 2.39 Å. There is one shorter (2.24 Å) and one longer (2.25 Å) Nd(2)-O(13) bond length. There are eight inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a body-centered cubic geometry to two equivalent O(12), two equivalent O(13), two equivalent O(14), and two equivalent O(15) atoms. There is one shorter (2.30 Å) and one longer (2.31 Å) Ce(1)-O(12) bond length. There is one shorter (2.44 Å) and one longer (2.47 Å) Ce(1)-O(13) bond length. There is one shorter (2.33 Å) and one longer (2.35 Å) Ce(1)-O(14) bond length. There is one shorter (2.38 Å) and one longer (2.41 Å) Ce(1)-O(15) bond length. In the second Ce site, Ce(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(16), two equivalent O(17), and two equivalent O(2) atoms. Both Ce(2)-O(1) bond lengths are 2.37 Å. Both Ce(2)-O(16) bond lengths are 2.38 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Ce(2)-O(17) bond length. Both Ce(2)-O(2) bond lengths are 2.38 Å. In the third Ce site, Ce(3) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(14), two equivalent O(15), and two equivalent O(16) atoms. Both Ce(3)-O(1) bond lengths are 2.38 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) Ce(3)-O(14) bond length. Both Ce(3)-O(15) bond lengths are 2.34 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Ce(3)-O(16) bond length. In the fourth Ce site, Ce(4) is bonded in a body-centered cubic geometry to two equivalent O(17), two equivalent O(18), two equivalent O(2), and two equivalent O(3) atoms. There is one shorter (2.38 Å) and one longer (2.39 Å) Ce(4)-O(17) bond length. There is one shorter (2.38 Å) and one longer (2.39 Å) Ce(4)-O(18) bond length. Both Ce(4)-O(2) bond lengths are 2.38 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Ce(4)-O(3) bond length. In the fifth Ce site, Ce(5) is bonded in a body-centered cubic geometry to two equivalent O(18), two equivalent O(19), two equivalent O(3), and two equivalent O(4) atoms. There is one shorter (2.36 Å) and one longer (2.38 Å) Ce(5)-O(18) bond length. There is one shorter (2.37 Å) and one longer (2.38 Å) Ce(5)-O(19) bond length. There is one shorter (2.37 Å) and one longer (2.39 Å) Ce(5)-O(3) bond length. There is one shorter (2.38 Å) and one longer (2.39 Å) Ce(5)-O(4) bond length. In the sixth Ce site, Ce(6) is bonded in a body-centered cubic geometry to two equivalent O(5), two equivalent O(6), two equivalent O(7), and two equivalent O(9) atoms. There is one shorter (2.38 Å) and one longer (2.39 Å) Ce(6)-O(5) bond length. Both Ce(6)-O(6) bond lengths are 2.37 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) Ce(6)-O(7) bond length. Both Ce(6)-O(9) bond lengths are 2.34 Å. In the seventh Ce site, Ce(7) is bonded in a body-centered cubic geometry to two equivalent O(19), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. There is one shorter (2.38 Å) and one longer (2.39 Å) Ce(7)-O(19) bond length. There is one shorter (2.37 Å) and one longer (2.38 Å) Ce(7)-O(4) bond length. There is one shorter (2.36 Å) and one longer (2.37 Å) Ce(7)-O(5) bond length. Both Ce(7)-O(6) bond lengths are 2.38 Å. In the eighth Ce site, Ce(8) is bonded in a body-centered cubic geometry to two equivalent O(10), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. There is one shorter (2.45 Å) and one longer (2.46 Å) Ce(8)-O(10) bond length. There is one shorter (2.34 Å) and one longer (2.35 Å) Ce(8)-O(7) bond length. Both Ce(8)-O(8) bond lengths are 2.30 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) Ce(8)-O(9) bond length. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ce(2) and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Ce(2) and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Ce(4) and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Ce(5) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ce(6) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Ce(6) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventh O site, O(7) is bonded to two equivalent Ce(6) and two equivalent Ce(8) atoms to form OCe4 tetrahedra that share corners with two equivalent O(10)Ce2Nd2 tetrahedra, corners with two equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(10)Ce2Nd2 tetrahedra,  an edgeedge with one O(6)Ce4 tetrahedra, and edges with four equivalent O(9)Ce4 tetrahedra. In the eighth O site, O(8) is bonded to two equivalent Nd(1) and two equivalent Ce(8) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(9)Ce4 tetrahedra, corners with two equivalent O(11)Nd4 tetrahedra, corners with four equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(7)Ce4 tetrahedra,  an edgeedge with one O(9)Ce4 tetrahedra,  an edgeedge with one O(11)Nd4 tetrahedra, and edges with four equivalent O(10)Ce2Nd2 tetrahedra. In the ninth O site, O(9) is bonded to two equivalent Ce(6) and two equivalent Ce(8) atoms to form OCe4 tetrahedra that share corners with two equivalent O(8)Ce2Nd2 tetrahedra, corners with two equivalent O(5)Ce4 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(6)Ce4 tetrahedra, corners with four equivalent O(9)Ce4 tetrahedra,  an edgeedge with one O(8)Ce2Nd2 tetrahedra,  an edgeedge with one O(5)Ce4 tetrahedra, and edges with four equivalent O(7)Ce4 tetrahedra. In the tenth O site, O(10) is bonded to two equivalent Nd(1) and two equivalent Ce(8) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(7)Ce4 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(9)Ce4 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(7)Ce4 tetrahedra, and edges with four equivalent O(8)Ce2Nd2 tetrahedra. In the eleventh O site, O(11) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(12)Ce2Nd2 tetrahedra, corners with two equivalent O(8)Ce2Nd2 tetrahedra, corners with four equivalent O(10)Ce2Nd2 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(12)Ce2Nd2 tetrahedra, and  an edgeedge with one O(8)Ce2Nd2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Nd(2) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(15)Ce4 tetrahedra, corners with two equivalent O(11)Nd4 tetrahedra, corners with four equivalent O(12)Ce2Nd2 tetrahedra, corners with four equivalent O(14)Ce4 tetrahedra,  an edgeedge with one O(15)Ce4 tetrahedra,  an edgeedge with one O(11)Nd4 tetrahedra, and edges with four equivalent O(13)Ce2Nd2 tetrahedra. In the thirteenth O site, O(13) is bonded to two equivalent Nd(2) and two equivalent Ce(1) atoms to form OCe2Nd2 tetrahedra that share corners with two equivalent O(14)Ce4 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(15)Ce4 tetrahedra, corners with four equivalent O(11)Nd4 tetrahedra,  an edgeedge with one O(14)Ce4 tetrahedra, and edges with four equivalent O(12)Ce2Nd2 tetrahedra. In the fourteenth O site, O(14) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(13)Ce2Nd2 tetrahedra, corners with two equivalent O(16)Ce4 tetrahedra, corners with four equivalent O(12)Ce2Nd2 tetrahedra, corners with four equivalent O(1)Ce4 tetrahedra, corners with four equivalent O(14)Ce4 tetrahedra,  an edgeedge with one O(13)Ce2Nd2 tetrahedra,  an edgeedge with one O(16)Ce4 tetrahedra, and edges with four equivalent O(15)Ce4 tetrahedra. In the fifteenth O site, O(15) is bonded to two equivalent Ce(1) and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(12)Ce2Nd2 tetrahedra, corners with two equivalent O(1)Ce4 tetrahedra, corners with four equivalent O(13)Ce2Nd2 tetrahedra, corners with four equivalent O(15)Ce4 tetrahedra, corners with four equivalent O(16)Ce4 tetrahedra,  an edgeedge with one O(12)Ce2Nd2 tetrahedra,  an edgeedge with one O(1)Ce4 tetrahedra, and edges with four equivalent O(14)Ce4 tetrahedra. In the sixteenth O site, O(16) is bonded to two equivalent Ce(2) and two equivalent Ce(3) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the seventeenth O site, O(17) is bonded to two equivalent Ce(2) and two equivalent Ce(4) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the eighteenth O site, O(18) is bonded to two equivalent Ce(4) and two equivalent Ce(5) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra. In the nineteenth O site, O(19) is bonded to two equivalent Ce(5) and two equivalent Ce(7) atoms to form a mixture of corner and edge-sharing OCe4 tetrahedra.