DOE OSTI2020
Eu3FeO6 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Eu3+ sites. In the first Eu3+ site, Eu3+ is bonded to seven O2- atoms to form distorted EuO7 pentagonal bipyramids that share corners with five EuO7 pentagonal bipyramids, corners with three equivalent FeO4 tetrahedra, edges with five EuO7 pentagonal bipyramids, an edgeedge with one FeO4 tetrahedra, and a faceface with one EuO7 pentagonal bipyramid. There are a spread of Eu–O bond distances ranging from 2.28–2.69 Å. In the second Eu3+ site, Eu3+ is bonded to seven O2- atoms to form distorted EuO7 pentagonal bipyramids that share corners with two equivalent EuO7 pentagonal bipyramids, a cornercorner with one FeO4 tetrahedra, edges with eight EuO7 pentagonal bipyramids, and an edgeedge with one FeO4 tetrahedra. There are a spread of Eu–O bond distances ranging from 2.36–2.51 Å. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with seven EuO7 pentagonal bipyramids and edges with three EuO7 pentagonal bipyramids. There is two shorter (1.88 Å) and two longer (1.90 Å) Fe–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Eu3+ atoms to form a mixture of corner and edge-sharing OEu4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Eu3+ and one Fe3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Eu3+ and one Fe3+ atom. In the fourth O2- site, O2- is bonded to three Eu3+ and one Fe3+ atom to form distorted corner-sharing OEu3Fe tetrahedra.