Materials Data on SrNd3Fe4(AsO)4 by Materials Project
SrNd3Fe4(AsO)4 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Sr2+ is bonded in a 4-coordinate geometry to four equivalent As3- and four equivalent O2- atoms. All Sr–As bond lengths are 3.46 Å. All Sr–O bond lengths are 2.46 Å. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a 4-coordinate geometry to four equivalent As3- and four equivalent O2- atoms. All Nd–As bond lengths are 3.54 Å. All Nd–O bond lengths are 2.30 Å. In the second Nd3+ site, Nd3+ is bonded in a 4-coordinate geometry to four As3- and four equivalent O2- atoms. All Nd–As bond lengths are 3.52 Å. All Nd–O bond lengths are 2.32 Å. Fe+2.25+ is bonded to four As3- atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. There are two shorter (2.61 Å) and two longer (2.62 Å) Fe–As bond lengths. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to four equivalent Nd3+ and four equivalent Fe+2.25+ atoms. In the second As3- site, As3- is bonded in a 8-coordinate geometry to four equivalent Nd3+ and four equivalent Fe+2.25+ atoms. In the third As3- site, As3- is bonded in a 8-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and four equivalent Fe+2.25+ atoms. O2- is bonded to one Sr2+ and three Nd3+ atoms to form a mixture of corner and edge-sharing OSrNd3 tetrahedra.