Materials Data on Tm(FeO2)2 by Materials Project
TmFe2O4 is Aluminum carbonitride-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent O2- atoms to form TmO6 octahedra that share corners with six equivalent FeO5 trigonal bipyramids and edges with six equivalent TmO6 octahedra. All Tm–O bond lengths are 2.26 Å. Fe+2.50+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with three equivalent TmO6 octahedra, corners with six equivalent FeO5 trigonal bipyramids, and edges with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. There are a spread of Fe–O bond distances ranging from 1.99–2.18 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Fe+2.50+ atoms to form OFe4 trigonal pyramids that share corners with four equivalent OTm3Fe 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 Tm3+ and one Fe+2.50+ atom to form OTm3Fe tetrahedra that share corners with nine equivalent OTm3Fe tetrahedra, corners with four equivalent OFe4 trigonal pyramids, and edges with three equivalent OTm3Fe tetrahedra.