Materials Data on NaAsSe2 by Materials Project

Abstract

NaAsSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with two equivalent AsSe6 octahedra, corners with four equivalent NaSe6 octahedra, edges with four equivalent NaSe6 octahedra, and edges with eight equivalent AsSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are four shorter (2.81 Å) and two longer (3.17 Å) Na–Se bond lengths. As3+ is bonded to six equivalent Se2- atoms to form AsSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent AsSe6 octahedra, edges with four equivalent AsSe6 octahedra, and edges with eight equivalent NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are two shorter (2.71 Å) and four longer (2.81 Å) As–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the second Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (2.71 Å) and two longer (2.81 Å) Se–As bond lengths. In the third Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (2.71 Å) and two longer (2.81 Å) Se–As bond lengths.