Sm2AsSe is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the third Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the fourth Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. As(1) is bonded to six Sm(1,1,1) atoms to form AsSm6 octahedra that share corners with two equivalent Se(1)Sm6 octahedra, corners with four equivalent As(1)Sm6 octahedra, edges with four equivalent As(1)Sm6 octahedra, and edges with eight equivalent Se(1)Sm6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Se(1) is bonded to six Sm(1,1,1) atoms to form SeSm6 octahedra that share corners with two equivalent As(1)Sm6 octahedra, corners with four equivalent Se(1)Sm6 octahedra, edges with four equivalent Se(1)Sm6 octahedra, and edges with eight equivalent As(1)Sm6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°.
Sm2AsSe is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There is one shorter (2.90 Å) and two longer (2.96 Å) Sm(1)-As(1) bond lengths. There are two shorter (2.96 Å) and one longer (3.04 Å) Sm(1)-Se(1) bond length. In the second Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There is one shorter (2.90 Å) and two longer (2.96 Å) Sm(1)-As(1) bond lengths. There are two shorter (2.96 Å) and one longer (3.04 Å) Sm(1)-Se(1) bond length. In the third Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There is one shorter (2.90 Å) and two longer (2.96 Å) Sm(1)-As(1) bond lengths. There are two shorter (2.96 Å) and one longer (3.04 Å) Sm(1)-Se(1) bond length. In the fourth Sm site, Sm(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing SmAs3Se3 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There is one shorter (2.90 Å) and two longer (2.96 Å) Sm(1)-As(1) bond lengths. There are two shorter (2.96 Å) and one longer (3.04 Å) Sm(1)-Se(1) bond length. As(1) is bonded to six Sm(1,1,1) atoms to form AsSm6 octahedra that share corners with two equivalent Se(1)Sm6 octahedra, corners with four equivalent As(1)Sm6 octahedra, edges with four equivalent As(1)Sm6 octahedra, and edges with eight equivalent Se(1)Sm6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Se(1) is bonded to six Sm(1,1,1) atoms to form SeSm6 octahedra that share corners with two equivalent As(1)Sm6 octahedra, corners with four equivalent Se(1)Sm6 octahedra, edges with four equivalent Se(1)Sm6 octahedra, and edges with eight equivalent As(1)Sm6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°.