Materials Data on K2B2S7 by Materials Project
K2B2S7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine S+1.14- atoms. There are a spread of K–S bond distances ranging from 3.27–3.72 Å. B3+ is bonded to four S+1.14- atoms to form corner-sharing BS4 tetrahedra. There is two shorter (1.91 Å) and two longer (1.93 Å) B–S bond length. There are four inequivalent S+1.14- sites. In the first S+1.14- site, S+1.14- is bonded in a distorted water-like geometry to two equivalent K1+ and two equivalent B3+ atoms. In the second S+1.14- site, S+1.14- is bonded in a distorted single-bond geometry to three equivalent K1+ and one B3+ atom. In the third S+1.14- site, S+1.14- is bonded in a distorted single-bond geometry to three equivalent K1+ and one B3+ atom. In the fourth S+1.14- site, S+1.14- is bonded in a distorted single-bond geometry to two equivalent K1+ and one B3+ atom.