Materials Data on KCr20O40 by Materials Project
KCr20O40 is zeta iron carbide-derived structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. K1+ is bonded in a distorted body-centered cubic geometry to eight equivalent O2- atoms. All K–O bond lengths are 2.97 Å. There are three inequivalent Cr+3.95+ sites. In the first Cr+3.95+ site, Cr+3.95+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.90–1.99 Å. In the second Cr+3.95+ site, Cr+3.95+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.89–1.97 Å. In the third Cr+3.95+ site, Cr+3.95+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.90–1.98 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Cr+3.95+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr+3.95+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr+3.95+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Cr+3.95+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+ and three Cr+3.95+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Cr+3.95+ atoms.