Materials Data on KEr(SO4)2 by Materials Project
KEr(SO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.63–3.34 Å. Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.23–2.53 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.48 Å) and two longer (1.49 Å) S–O bond length. In the second S6+ site, S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.48–1.51 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Er3+, and one S6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Er3+, and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Er3+, and one S6+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Er3+, and one S6+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one Er3+, and one S6+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to one Er3+ and one S6+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Er3+, and one S6+ atom.