Materials Data on Na2CoAsCO7 by Materials Project
Na2CoCAsO7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.84 Å. Co3+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with four equivalent AsO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.96–2.16 Å. C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.25–1.33 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CoO6 octahedra. The corner-sharing octahedra tilt angles range from 45–57°. There are a spread of As–O bond distances ranging from 1.71–1.75 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+ and one C4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na1+, one Co3+, and one C4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Co3+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Co3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Na1+, one Co3+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Na1+, one Co3+, and one As5+ atom.