LiAsSe2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form LiSe6 octahedra that share corners with six equivalent Li(1)Se6 octahedra, corners with four equivalent As(1)Se4 trigonal pyramids, edges with four equivalent Li(1)Se6 octahedra, and edges with three equivalent As(1)Se4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 2-6°. As(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form distorted AsSe4 trigonal pyramids that share corners with four equivalent Li(1)Se6 octahedra, corners with two equivalent As(1)Se4 trigonal pyramids, edges with three equivalent Li(1)Se6 octahedra, and edges with two equivalent As(1)Se4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 79-87°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Li(1) and three equivalent As(1) atoms to form distorted SeLi2As3 square pyramids that share corners with four equivalent Se(1)Li2As3 square pyramids, corners with five equivalent Se(2)Li4As square pyramids, edges with two equivalent Se(1)Li2As3 square pyramids, and edges with three equivalent Se(2)Li4As square pyramids. In the second Se site, Se(2) is bonded to four equivalent Li(1) and one As(1) atom to form SeLi4As square pyramids that share corners with four equivalent Se(2)Li4As square pyramids, corners with five equivalent Se(1)Li2As3 square pyramids, edges with three equivalent Se(1)Li2As3 square pyramids, and edges with four equivalent Se(2)Li4As square pyramids.
LiAsSe2 crystallizes in the triclinic P-1 space group. Li(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form LiSe6 octahedra that share corners with six equivalent Li(1)Se6 octahedra, corners with four equivalent As(1)Se4 trigonal pyramids, edges with four equivalent Li(1)Se6 octahedra, and edges with three equivalent As(1)Se4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 2-6°. There is one shorter (2.85 Å) and one longer (2.87 Å) Li(1)-Se(1) bond length. There are a spread of Li(1)-Se(2) bond distances ranging from 2.72-2.86 Å. As(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form distorted AsSe4 trigonal pyramids that share corners with four equivalent Li(1)Se6 octahedra, corners with two equivalent As(1)Se4 trigonal pyramids, edges with three equivalent Li(1)Se6 octahedra, and edges with two equivalent As(1)Se4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 79-87°. The As(1)-Se(2) bond length is 2.32 Å. There are a spread of As(1)-Se(1) bond distances ranging from 2.46-2.79 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Li(1) and three equivalent As(1) atoms to form distorted SeLi2As3 square pyramids that share corners with four equivalent Se(1)Li2As3 square pyramids, corners with five equivalent Se(2)Li4As square pyramids, edges with two equivalent Se(1)Li2As3 square pyramids, and edges with three equivalent Se(2)Li4As square pyramids. In the second Se site, Se(2) is bonded to four equivalent Li(1) and one As(1) atom to form SeLi4As square pyramids that share corners with four equivalent Se(2)Li4As square pyramids, corners with five equivalent Se(1)Li2As3 square pyramids, edges with three equivalent Se(1)Li2As3 square pyramids, and edges with four equivalent Se(2)Li4As square pyramids.