Li3NdAs2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to six equivalent Li(2), two equivalent Nd(1), and six equivalent As(1) atoms to form distorted LiLi6Nd2As6 cuboctahedra that share corners with two equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with twelve equivalent Nd(1)Li2As6 octahedra, corners with six equivalent Li(2)Li3As4 tetrahedra, faces with six equivalent Li(1)Li6Nd2As6 cuboctahedra, faces with two equivalent Nd(1)Li2As6 octahedra, and faces with six equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the second Li site, Li(2) is bonded to three equivalent Li(1) and four equivalent As(1) atoms to form distorted LiLi3As4 tetrahedra that share corners with three equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with three equivalent Nd(1)Li2As6 octahedra, corners with three equivalent Li(2)Li3As4 tetrahedra, edges with three equivalent Nd(1)Li2As6 octahedra, edges with six equivalent Li(2)Li3As4 tetrahedra, faces with three equivalent Li(1)Li6Nd2As6 cuboctahedra, faces with three equivalent Nd(1)Li2As6 octahedra, and faces with three equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedral tilt angles are 21°. Nd(1) is bonded to two equivalent Li(1) and six equivalent As(1) atoms to form NdLi2As6 octahedra that share corners with twelve equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with two equivalent Nd(1)Li2As6 octahedra, corners with six equivalent Li(2)Li3As4 tetrahedra, edges with six equivalent Nd(1)Li2As6 octahedra, edges with six equivalent Li(2)Li3As4 tetrahedra, faces with two equivalent Li(1)Li6Nd2As6 cuboctahedra, and faces with six equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedra are not tilted. As(1) is bonded in a 10-coordinate geometry to three equivalent Li(1), four equivalent Li(2), and three equivalent Nd(1) atoms.
Li3NdAs2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to six equivalent Li(2), two equivalent Nd(1), and six equivalent As(1) atoms to form distorted LiLi6Nd2As6 cuboctahedra that share corners with two equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with twelve equivalent Nd(1)Li2As6 octahedra, corners with six equivalent Li(2)Li3As4 tetrahedra, faces with six equivalent Li(1)Li6Nd2As6 cuboctahedra, faces with two equivalent Nd(1)Li2As6 octahedra, and faces with six equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. All Li(1)-Li(2) bond lengths are 2.67 Å. Both Li(1)-Nd(1) bond lengths are 3.47 Å. All Li(1)-As(1) bond lengths are 2.99 Å. In the second Li site, Li(2) is bonded to three equivalent Li(1) and four equivalent As(1) atoms to form distorted LiLi3As4 tetrahedra that share corners with three equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with three equivalent Nd(1)Li2As6 octahedra, corners with three equivalent Li(2)Li3As4 tetrahedra, edges with three equivalent Nd(1)Li2As6 octahedra, edges with six equivalent Li(2)Li3As4 tetrahedra, faces with three equivalent Li(1)Li6Nd2As6 cuboctahedra, faces with three equivalent Nd(1)Li2As6 octahedra, and faces with three equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedral tilt angles are 21°. There are three shorter (2.57 Å) and one longer (2.68 Å) Li(2)-As(1) bond length. Nd(1) is bonded to two equivalent Li(1) and six equivalent As(1) atoms to form NdLi2As6 octahedra that share corners with twelve equivalent Li(1)Li6Nd2As6 cuboctahedra, corners with two equivalent Nd(1)Li2As6 octahedra, corners with six equivalent Li(2)Li3As4 tetrahedra, edges with six equivalent Nd(1)Li2As6 octahedra, edges with six equivalent Li(2)Li3As4 tetrahedra, faces with two equivalent Li(1)Li6Nd2As6 cuboctahedra, and faces with six equivalent Li(2)Li3As4 tetrahedra. The corner-sharing octahedra are not tilted. All Nd(1)-As(1) bond lengths are 3.06 Å. As(1) is bonded in a 10-coordinate geometry to three equivalent Li(1), four equivalent Li(2), and three equivalent Nd(1) atoms.