Materials Data on K2In12Se19 by Materials Project
K2In12Se19 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are three shorter (3.44 Å) and three longer (3.60 Å) K–Se bond lengths. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form InSe4 tetrahedra that share corners with two equivalent InSe4 tetrahedra and corners with four equivalent InSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.58–2.71 Å. In the second In3+ site, In3+ is bonded to five Se2- atoms to form InSe5 trigonal bipyramids that share corners with four equivalent InSe4 tetrahedra, corners with three equivalent InSe5 trigonal bipyramids, and edges with three equivalent InSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.60–3.24 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to one K1+ and two equivalent In3+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to one K1+ and three In3+ atoms. In the third Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three In3+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted octahedral geometry to six equivalent In3+ atoms.