DOE OSTI2020
Gd3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded to seven O2- atoms to form distorted GdO7 pentagonal bipyramids that share a cornercorner with one GaO4 tetrahedra, edges with two equivalent GdO7 pentagonal bipyramids, and an edgeedge with one GaO4 tetrahedra. There are a spread of Gd–O bond distances ranging from 2.32–2.49 Å. In the second Gd3+ site, Gd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Gd–O bond distances ranging from 2.25–2.63 Å. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one GdO7 pentagonal bipyramid and an edgeedge with one GdO7 pentagonal bipyramid. There is one shorter (1.86 Å) and three longer (1.89 Å) Ga–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three Gd3+ and one Ga3+ atom to form distorted OGd3Ga tetrahedra that share corners with eight equivalent OGd4 tetrahedra, corners with four equivalent OGd3Ga trigonal pyramids, and edges with two equivalent OGd3Ga trigonal pyramids. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Gd3+ and one Ga3+ atom. In the third O2- site, O2- is bonded to four Gd3+ atoms to form OGd4 tetrahedra that share corners with six OGd3Ga tetrahedra, corners with six equivalent OGd3Ga trigonal pyramids, edges with three equivalent OGd4 tetrahedra, and an edgeedge with one OGd3Ga trigonal pyramid. In the fourth O2- site, O2- is bonded to three Gd3+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing OGd3Ga trigonal pyramids.