Materials Data on Ca2Ta2CuO8 by Materials Project
Ca2Ta2CuO8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.57 Å. In the second Ca2+ site, Ca2+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.25–2.83 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted edge-sharing TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.88–2.27 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted edge-sharing TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.87–2.28 Å. Cu2+ is bonded in a see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.88–2.20 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ta5+ and one Cu2+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ta5+ and one Cu2+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ta5+ and one Cu2+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one Cu2+ atom. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded to three Ca2+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing OCa3Ta trigonal pyramids. In the eighth O2- site, O2- is bonded to three Ca2+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing OCa3Ta trigonal pyramids.