Materials Data on BaCaO2 by Materials Project
BaCaO2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba2+ is bonded to six O2- atoms to form BaO6 octahedra that share corners with six equivalent BaO6 octahedra, edges with four equivalent BaO6 octahedra, and edges with eight equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.65 Å) and four longer (2.66 Å) Ba–O bond lengths. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent CaO6 octahedra, edges with four equivalent CaO6 octahedra, and edges with eight equivalent BaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.65 Å) and four longer (2.66 Å) Ca–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Ca2+ atoms to form a mixture of corner and edge-sharing OBa4Ca2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent Ca2+ atoms to form OBa2Ca4 octahedra that share corners with six equivalent OBa2Ca4 octahedra and edges with twelve OBa4Ca2 octahedra. The corner-sharing octahedral tilt angles are 0°.