Materials Data on KErP2S7 by Materials Project
KErP2S7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of K–S bond distances ranging from 3.31–3.59 Å. Er3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Er–S bond distances ranging from 2.75–3.10 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are a spread of P–S bond distances ranging from 2.02–2.15 Å. In the second P5+ site, P5+ is bonded to four S2- atoms to form corner-sharing PS4 tetrahedra. There are a spread of P–S bond distances ranging from 2.03–2.14 Å. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Er3+, and one P5+ atom. In the second S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Er3+ and one P5+ atom. In the third S2- site, S2- is bonded in a 3-coordinate geometry to one K1+, one Er3+, and one P5+ atom. In the fourth S2- site, S2- is bonded in a distorted T-shaped geometry to two equivalent Er3+ and one P5+ atom. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Er3+, and one P5+ atom. In the sixth S2- site, S2- is bonded in a 2-coordinate geometry to one K1+ and two P5+ atoms. In the seventh S2- site, S2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Er3+, and one P5+ atom.