Materials Data on Na5Co2S5 by Materials Project

Abstract

Na5Co2S5 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five S2- atoms. There are a spread of Na–S bond distances ranging from 2.65–2.96 Å. In the second Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with two equivalent NaS6 octahedra and corners with eight equivalent CoS4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Na–S bond distances ranging from 2.68–3.01 Å. Co+2.50+ is bonded to four equivalent S2- atoms to form CoS4 tetrahedra that share corners with four equivalent NaS6 octahedra and edges with two equivalent CoS4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–45°. There are two shorter (2.18 Å) and two longer (2.19 Å) Co–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to five Na1+ and two equivalent Co+2.50+ atoms to form distorted SNa5Co2 pentagonal bipyramids that share corners with three equivalent SNa6 octahedra, corners with five equivalent SNa5Co2 pentagonal bipyramids, edges with five equivalent SNa5Co2 pentagonal bipyramids, a faceface with one SNa6 octahedra, and faces with two equivalent SNa5Co2 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–84°. In the second S2- site, S2- is bonded to six Na1+ atoms to form distorted SNa6 octahedra that share corners with two equivalent SNa6 octahedra, corners with twelve equivalent SNa5Co2 pentagonal bipyramids, and faces with four equivalent SNa5Co2 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 0°.