Materials Data on Sm2As4O9 by Materials Project
Sm2As4O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sm–O bond distances ranging from 2.36–2.87 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.36–2.71 Å. There are four inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.76–1.88 Å. In the second As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.75–1.88 Å. In the third As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.75–1.90 Å. In the fourth As3+ site, As3+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.76–1.93 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Sm3+ and one As3+ atom. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Sm3+ and two As3+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two As3+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Sm3+ and one As3+ atom. In the fifth O2- site, O2- is bonded to three Sm3+ and one As3+ atom to form distorted edge-sharing OSm3As tetrahedra. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Sm3+ and one As3+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Sm3+ and one As3+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Sm3+ and one As3+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sm3+ and two As3+ atoms.