Materials Data on Ca3(Ru2O7)2 by Materials Project
Ca3(Ru2O7)2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ca2+ is bonded to eight O2- atoms to form distorted CaO8 hexagonal bipyramids that share edges with four equivalent CaO8 hexagonal bipyramids and edges with six RuO6 octahedra. There are two shorter (2.20 Å) and six longer (2.60 Å) Ca–O bond lengths. There are two inequivalent Ru+5.50+ sites. In the first Ru+5.50+ site, Ru+5.50+ is bonded to six equivalent O2- atoms to form RuO6 octahedra that share corners with six equivalent RuO6 octahedra and edges with six equivalent CaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. All Ru–O bond lengths are 1.95 Å. In the second Ru+5.50+ site, Ru+5.50+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with six RuO6 octahedra and edges with four equivalent CaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–43°. There is four shorter (1.93 Å) and two longer (1.95 Å) Ru–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three equivalent Ca2+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Ru+5.50+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two Ru+5.50+ atoms.