Materials Data on SrCdAs2O7 by Materials Project
SrCdAs2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.55–3.21 Å. Cd2+ is bonded to six O2- atoms to form distorted CdO6 octahedra that share corners with six AsO4 tetrahedra and an edgeedge with one CdO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.27–2.51 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CdO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of As–O bond distances ranging from 1.69–1.80 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CdO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of As–O bond distances ranging from 1.69–1.80 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sr2+, one Cd2+, and one As5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent Sr2+ and one As5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sr2+, one Cd2+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+, two equivalent Cd2+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, one Cd2+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+, one Cd2+, and one As5+ atom.