Materials Data on K2TeOF4 by Materials Project
K2TeOF4 crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of two K2TeOF4 sheets oriented in the (0, 1, 0) direction. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to one O2- and four equivalent F1- atoms to form distorted KOF4 square pyramids that share corners with five equivalent TeOF4 square pyramids and faces with four equivalent KO4F8 cuboctahedra. The K–O bond length is 2.71 Å. All K–F bond lengths are 2.61 Å. In the second K1+ site, K1+ is bonded to four equivalent O2- and eight equivalent F1- atoms to form distorted KO4F8 cuboctahedra that share corners with four equivalent KO4F8 cuboctahedra, faces with four equivalent KO4F8 cuboctahedra, faces with four equivalent KOF4 square pyramids, and faces with four equivalent TeOF4 square pyramids. There are two shorter (3.22 Å) and two longer (3.37 Å) K–O bond lengths. There are four shorter (2.99 Å) and four longer (3.12 Å) K–F bond lengths. Te4+ is bonded to one O2- and four equivalent F1- atoms to form TeOF4 square pyramids that share corners with five equivalent KOF4 square pyramids and faces with four equivalent KO4F8 cuboctahedra. The Te–O bond length is 1.82 Å. All Te–F bond lengths are 2.10 Å. O2- is bonded in a 1-coordinate geometry to five K1+ and one Te4+ atom. F1- is bonded in a 2-coordinate geometry to three K1+ and one Te4+ atom.