Materials Data on CaEu4O5 by Materials Project
CaEu4O5 is Caswellsilverite-like structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent EuO6 octahedra, and edges with twelve equivalent EuO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.46 Å) and two longer (2.52 Å) Ca–O bond lengths. Eu2+ is bonded to six O2- atoms to form EuO6 octahedra that share a cornercorner with one CaO6 octahedra, corners with five equivalent EuO6 octahedra, edges with three equivalent CaO6 octahedra, and edges with nine equivalent EuO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Eu–O bond distances ranging from 2.51–2.58 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and five equivalent Eu2+ atoms to form a mixture of edge and corner-sharing OCaEu5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O2- site, O2- is bonded to two equivalent Ca2+ and four equivalent Eu2+ atoms to form OCa2Eu4 octahedra that share corners with six OCa2Eu4 octahedra and edges with twelve equivalent OCaEu5 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.