Materials Data on Sm2As2O5 by Materials Project
Sm2As2O5 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sm3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are four shorter (2.24 Å) and one longer (2.40 Å) Sm–O bond lengths. There are two inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All As–O bond lengths are 2.28 Å. In the second As2+ site, As2+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. All As–O bond lengths are 2.68 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent As2+ atoms to form a mixture of corner and edge-sharing OSm2As2 tetrahedra. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Sm3+ and four equivalent As2+ atoms.