DOE OSTI2020
NaLi(AsS2)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with two equivalent LiS6 octahedra, corners with four equivalent NaS6 octahedra, and edges with four equivalent LiS6 octahedra. The corner-sharing octahedra tilt angles range from 11–16°. There are a spread of Na–S bond distances ranging from 2.78–3.07 Å. Li1+ is bonded to six S2- atoms to form LiS6 octahedra that share corners with two equivalent NaS6 octahedra, corners with four equivalent LiS6 octahedra, and edges with four equivalent NaS6 octahedra. The corner-sharing octahedra tilt angles range from 11–16°. There are a spread of Li–S bond distances ranging from 2.72–2.89 Å. There are two inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.20–2.38 Å. In the second As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.20–2.37 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Na1+, two equivalent Li1+, and one As3+ atom to form a mixture of edge and corner-sharing SNa2Li2As square pyramids. In the second S2- site, S2- is bonded to two equivalent Na1+, two equivalent Li1+, and one As3+ atom to form a mixture of edge and corner-sharing SNa2Li2As square pyramids. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Na1+, one Li1+, and two As3+ atoms. In the fourth S2- site, S2- is bonded in a distorted see-saw-like geometry to one Na1+, one Li1+, and two As3+ atoms.