Materials Data on Na2Cu2Si4O11 by Materials Project
Na2Cu2Si4O11 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.76 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with five SiO4 tetrahedra and edges with two equivalent CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.44 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent CuO5 square pyramids and corners with two equivalent SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent CuO5 square pyramids and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two equivalent Cu2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, two equivalent Cu2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+, one Cu2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms.