Nd2SeO2 crystallizes in the trigonal P-3m1 space group. Nd(1) is bonded in a 7-coordinate geometry to three equivalent Se(1) and four equivalent O(1) atoms. Se(1) is bonded to six equivalent Nd(1) atoms to form SeNd6 octahedra that share corners with twelve equivalent O(1)Nd4 tetrahedra, edges with six equivalent Se(1)Nd6 octahedra, and edges with six equivalent O(1)Nd4 tetrahedra. O(1) is bonded to four equivalent Nd(1) atoms to form ONd4 tetrahedra that share corners with six equivalent Se(1)Nd6 octahedra, corners with six equivalent O(1)Nd4 tetrahedra, edges with three equivalent Se(1)Nd6 octahedra, and edges with three equivalent O(1)Nd4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-49°.
Nd2SeO2 crystallizes in the trigonal P-3m1 space group. Nd(1) is bonded in a 7-coordinate geometry to three equivalent Se(1) and four equivalent O(1) atoms. All Nd(1)-Se(1) bond lengths are 3.08 Å. There is one shorter (2.37 Å) and three longer (2.39 Å) Nd(1)-O(1) bond lengths. Se(1) is bonded to six equivalent Nd(1) atoms to form SeNd6 octahedra that share corners with twelve equivalent O(1)Nd4 tetrahedra, edges with six equivalent Se(1)Nd6 octahedra, and edges with six equivalent O(1)Nd4 tetrahedra. O(1) is bonded to four equivalent Nd(1) atoms to form ONd4 tetrahedra that share corners with six equivalent Se(1)Nd6 octahedra, corners with six equivalent O(1)Nd4 tetrahedra, edges with three equivalent Se(1)Nd6 octahedra, and edges with three equivalent O(1)Nd4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-49°.