Materials Data on KFeS2 by Materials Project
KFeS2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded to eight equivalent S2- atoms to form distorted KS8 hexagonal bipyramids that share corners with four equivalent KS8 hexagonal bipyramids, corners with six equivalent FeS4 tetrahedra, edges with six equivalent KS8 hexagonal bipyramids, edges with five equivalent FeS4 tetrahedra, and faces with two equivalent KS8 hexagonal bipyramids. There are a spread of K–S bond distances ranging from 3.37–3.45 Å. Fe3+ is bonded to four equivalent S2- atoms to form FeS4 tetrahedra that share corners with six equivalent KS8 hexagonal bipyramids, edges with five equivalent KS8 hexagonal bipyramids, and edges with two equivalent FeS4 tetrahedra. There are two shorter (2.18 Å) and two longer (2.19 Å) Fe–S bond lengths. S2- is bonded in a 6-coordinate geometry to four equivalent K1+ and two equivalent Fe3+ atoms.