Nd3Mn2Sb3O14 crystallizes in the trigonal R-3m space group. Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to six equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted MnO8 hexagonal bipyramids that share edges with six equivalent Sb(1)O6 octahedra. Sb(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form SbO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Mn(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-56°. There are three inequivalent O sites. In the first O site, O(3) is bonded to two equivalent Nd(1), one Mn(1), and one Sb(1) atom to form distorted ONd2MnSb tetrahedra that share corners with two equivalent O(1)Nd3Mn tetrahedra, corners with eight equivalent O(3)Nd2MnSb tetrahedra, corners with four equivalent O(2)NdMnSb2 trigonal pyramids,  an edgeedge with one O(1)Nd3Mn tetrahedra, edges with two equivalent O(3)Nd2MnSb tetrahedra, and edges with two equivalent O(2)NdMnSb2 trigonal pyramids. In the second O site, O(1) is bonded to three equivalent Nd(1) and one Mn(2) atom to form ONd3Mn tetrahedra that share corners with four equivalent O(1)Nd3Mn tetrahedra, corners with six equivalent O(3)Nd2MnSb tetrahedra, corners with six equivalent O(2)NdMnSb2 trigonal pyramids, edges with three equivalent O(3)Nd2MnSb tetrahedra, and edges with three equivalent O(2)NdMnSb2 trigonal pyramids. In the third O site, O(2) is bonded to one Nd(1), one Mn(2), and two equivalent Sb(1) atoms to form distorted ONdMnSb2 trigonal pyramids that share corners with two equivalent O(1)Nd3Mn tetrahedra, corners with four equivalent O(3)Nd2MnSb tetrahedra, corners with eight equivalent O(2)NdMnSb2 trigonal pyramids,  an edgeedge with one O(1)Nd3Mn tetrahedra, edges with two equivalent O(3)Nd2MnSb tetrahedra, and edges with two equivalent O(2)NdMnSb2 trigonal pyramids.
Nd3Mn2Sb3O14 crystallizes in the trigonal R-3m space group. Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Both Nd(1)-O(1) bond lengths are 2.37 Å. Both Nd(1)-O(2) bond lengths are 2.63 Å. All Nd(1)-O(3) bond lengths are 2.53 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to six equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. All Mn(1)-O(3) bond lengths are 2.20 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted MnO8 hexagonal bipyramids that share edges with six equivalent Sb(1)O6 octahedra. Both Mn(2)-O(1) bond lengths are 2.05 Å. All Mn(2)-O(2) bond lengths are 2.66 Å. Sb(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form SbO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Mn(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-56°. Both Sb(1)-O(3) bond lengths are 1.97 Å. All Sb(1)-O(2) bond lengths are 2.04 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded to two equivalent Nd(1), one Mn(1), and one Sb(1) atom to form distorted ONd2MnSb tetrahedra that share corners with two equivalent O(1)Nd3Mn tetrahedra, corners with eight equivalent O(3)Nd2MnSb tetrahedra, corners with four equivalent O(2)NdMnSb2 trigonal pyramids,  an edgeedge with one O(1)Nd3Mn tetrahedra, edges with two equivalent O(3)Nd2MnSb tetrahedra, and edges with two equivalent O(2)NdMnSb2 trigonal pyramids. In the second O site, O(1) is bonded to three equivalent Nd(1) and one Mn(2) atom to form ONd3Mn tetrahedra that share corners with four equivalent O(1)Nd3Mn tetrahedra, corners with six equivalent O(3)Nd2MnSb tetrahedra, corners with six equivalent O(2)NdMnSb2 trigonal pyramids, edges with three equivalent O(3)Nd2MnSb tetrahedra, and edges with three equivalent O(2)NdMnSb2 trigonal pyramids. In the third O site, O(2) is bonded to one Nd(1), one Mn(2), and two equivalent Sb(1) atoms to form distorted ONdMnSb2 trigonal pyramids that share corners with two equivalent O(1)Nd3Mn tetrahedra, corners with four equivalent O(3)Nd2MnSb tetrahedra, corners with eight equivalent O(2)NdMnSb2 trigonal pyramids,  an edgeedge with one O(1)Nd3Mn tetrahedra, edges with two equivalent O(3)Nd2MnSb tetrahedra, and edges with two equivalent O(2)NdMnSb2 trigonal pyramids.