Materials Data on Sm(FeO2)2 by Materials Project

Abstract

Sm(FeO2)2 is Aluminum carbonitride-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Sm3+ is bonded to six O2- atoms to form distorted SmO6 octahedra that share corners with six FeO5 trigonal bipyramids and edges with six equivalent SmO6 octahedra. There are three shorter (2.33 Å) and three longer (2.36 Å) Sm–O bond lengths. There are two inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with three equivalent SmO6 octahedra, corners with six equivalent FeO5 trigonal bipyramids, and edges with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 62–65°. There are a spread of Fe–O bond distances ranging from 2.04–2.26 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with three equivalent SmO6 octahedra, corners with six equivalent FeO5 trigonal bipyramids, and edges with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of Fe–O bond distances ranging from 1.93–2.12 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Fe+2.50+ atoms to form OFe4 trigonal pyramids that share corners with four OSm3Fe tetrahedra, corners with six equivalent OFe4 trigonal pyramids, and edges with three equivalent OFe4 trigonal pyramids. In the second O2- site, O2- is bonded to three equivalent Sm3+ and one Fe+2.50+ atom to form OSm3Fe tetrahedra that share corners with nine OSm3Fe tetrahedra, corners with four OFe4 trigonal pyramids, and edges with three equivalent OSm3Fe tetrahedra. In the third O2- site, O2- is bonded to three equivalent Sm3+ and one Fe+2.50+ atom to form distorted OSm3Fe tetrahedra that share corners with nine OSm3Fe tetrahedra, corners with four OFe4 trigonal pyramids, and edges with three equivalent OSm3Fe tetrahedra. In the fourth O2- site, O2- is bonded to four Fe+2.50+ atoms to form OFe4 trigonal pyramids that share corners with four OSm3Fe tetrahedra, corners with six equivalent OFe4 trigonal pyramids, and edges with three equivalent OFe4 trigonal pyramids.